Merge remote-tracking branch 'obsidian/misc-ca' into derivation-primop-floating-output

.version

@@ -1 +1 @@
-2.4
+3.0

doc/manual/command-ref/conf-file.xml

@@ -370,34 +370,6 @@ false</literal>.</para>
 
   </varlistentry>
 
-  <varlistentry xml:id="conf-hashed-mirrors"><term><literal>hashed-mirrors</literal></term>
-
-    <listitem><para>A list of web servers used by
-    <function>builtins.fetchurl</function> to obtain files by
-    hash. The default is
-    <literal>http://tarballs.nixos.org/</literal>. Given a hash type
-    <replaceable>ht</replaceable> and a base-16 hash
-    <replaceable>h</replaceable>, Nix will try to download the file
-    from
-    <literal>hashed-mirror/<replaceable>ht</replaceable>/<replaceable>h</replaceable></literal>.
-    This allows files to be downloaded even if they have disappeared
-    from their original URI. For example, given the default mirror
-    <literal>http://tarballs.nixos.org/</literal>, when building the derivation
-
-<programlisting>
-builtins.fetchurl {
-  url = "https://example.org/foo-1.2.3.tar.xz";
-  sha256 = "2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae";
-}
-</programlisting>
-
-    Nix will attempt to download this file from
-    <literal>http://tarballs.nixos.org/sha256/2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae</literal>
-    first. If it is not available there, if will try the original URI.</para></listitem>
-
-  </varlistentry>
-
-
   <varlistentry xml:id="conf-http-connections"><term><literal>http-connections</literal></term>
 
     <listitem><para>The maximum number of parallel TCP connections

perl/lib/Nix/Store.xs

@@ -224,7 +224,7 @@ SV * hashString(char * algo, int base32, char * s)
 SV * convertHash(char * algo, char * s, int toBase32)
     PPCODE:
         try {
-            Hash h(s, parseHashType(algo));
+            auto h = Hash::parseAny(s, parseHashType(algo));
             string s = h.to_string(toBase32 ? Base32 : Base16, false);
             XPUSHs(sv_2mortal(newSVpv(s.c_str(), 0)));
         } catch (Error & e) {
@@ -285,7 +285,7 @@ SV * addToStore(char * srcPath, int recursive, char * algo)
 SV * makeFixedOutputPath(int recursive, char * algo, char * hash, char * name)
     PPCODE:
         try {
-            Hash h(hash, parseHashType(algo));
+            auto h = Hash::parseAny(hash, parseHashType(algo));
             auto method = recursive ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
             auto path = store()->makeFixedOutputPath(method, h, name);
             XPUSHs(sv_2mortal(newSVpv(store()->printStorePath(path).c_str(), 0)));

scripts/install-multi-user.sh

@@ -37,6 +37,8 @@ readonly PROFILE_NIX_FILE="$NIX_ROOT/var/nix/profiles/default/etc/profile.d/nix-
 
 readonly NIX_INSTALLED_NIX="@nix@"
 readonly NIX_INSTALLED_CACERT="@cacert@"
+#readonly NIX_INSTALLED_NIX="/nix/store/j8dbv5w6jl34caywh2ygdy88knx1mdf7-nix-2.3.6"
+#readonly NIX_INSTALLED_CACERT="/nix/store/7dxhzymvy330i28ii676fl1pqwcahv2f-nss-cacert-3.49.2"
 readonly EXTRACTED_NIX_PATH="$(dirname "$0")"
 
 readonly ROOT_HOME=$(echo ~root)
@@ -69,9 +71,11 @@ uninstall_directions() {
     subheader "Uninstalling nix:"
     local step=0
 
-    if poly_service_installed_check; then
+    if [ -e /run/systemd/system ] && poly_service_installed_check; then
         step=$((step + 1))
         poly_service_uninstall_directions "$step"
+    else
+        step=$((step + 1))
     fi
 
     for profile_target in "${PROFILE_TARGETS[@]}"; do
@@ -250,7 +254,9 @@ function finish_success {
         echo "But fetching the nixpkgs channel failed. (Are you offline?)"
         echo "To try again later, run \"sudo -i nix-channel --update nixpkgs\"."
     fi
-    cat <<EOF
+
+    if [ -e /run/systemd/system ]; then
+        cat <<EOF
 
 Before Nix will work in your existing shells, you'll need to close
 them and open them again. Other than that, you should be ready to go.
@@ -264,6 +270,26 @@ hesitate:
 
 $(contactme)
 EOF
+    else
+        cat <<EOF
+
+Before Nix will work in your existing shells, you'll need to close
+them and open them again. Other than that, you should be ready to go.
+
+Try it! Open a new terminal, and type:
+
+  $ sudo nix-daemon
+  $ nix-shell -p nix-info --run "nix-info -m"
+
+Additionally, you may want to add nix-daemon to your init-system.
+
+Thank you for using this installer. If you have any feedback, don't
+hesitate:
+
+$(contactme)
+EOF
+   fi
+
 }
 
 
@@ -664,12 +690,8 @@ main() {
         # shellcheck source=./install-darwin-multi-user.sh
         . "$EXTRACTED_NIX_PATH/install-darwin-multi-user.sh"
     elif [ "$(uname -s)" = "Linux" ]; then
-        if [ -e /run/systemd/system ]; then
+        # shellcheck source=./install-systemd-multi-user.sh
-            # shellcheck source=./install-systemd-multi-user.sh
+        . "$EXTRACTED_NIX_PATH/install-systemd-multi-user.sh" # most of this works on non-systemd distros also
-            . "$EXTRACTED_NIX_PATH/install-systemd-multi-user.sh"
-        else
-            failure "Sorry, the multi-user installation requires systemd on Linux (detected using /run/systemd/system)"
-        fi
     else
         failure "Sorry, I don't know what to do on $(uname)"
     fi
@@ -702,7 +724,10 @@ main() {
 
     setup_default_profile
     place_nix_configuration
-    poly_configure_nix_daemon_service
+
+    if [ -e /run/systemd/system ]; then
+        poly_configure_nix_daemon_service
+    fi
 
     trap finish_success EXIT
 }

scripts/install-nix-from-closure.sh

@@ -35,7 +35,7 @@ fi
 # Determine if we could use the multi-user installer or not
 if [ "$(uname -s)" = "Darwin" ]; then
     echo "Note: a multi-user installation is possible. See https://nixos.org/nix/manual/#sect-multi-user-installation" >&2
-elif [ "$(uname -s)" = "Linux" ] && [ -e /run/systemd/system ]; then
+elif [ "$(uname -s)" = "Linux" ]; then
     echo "Note: a multi-user installation is possible. See https://nixos.org/nix/manual/#sect-multi-user-installation" >&2
 fi
 
@@ -122,7 +122,7 @@ if [ "$(uname -s)" = "Darwin" ]; then
 fi
 
 if [ "$INSTALL_MODE" = "daemon" ]; then
-    printf '\e[1;31mSwitching to the Daemon-based Installer\e[0m\n'
+    printf '\e[1;31mSwitching to the Multi-user Installer\e[0m\n'
     exec "$self/install-multi-user"
     exit 0
 fi

src/build-remote/build-remote.cc

@@ -33,7 +33,7 @@ std::string escapeUri(std::string uri)
 
 static string currentLoad;
 
-static AutoCloseFD openSlotLock(const Machine & m, unsigned long long slot)
+static AutoCloseFD openSlotLock(const Machine & m, uint64_t slot)
 {
     return openLockFile(fmt("%s/%s-%d", currentLoad, escapeUri(m.storeUri), slot), true);
 }
@@ -119,7 +119,7 @@ static int _main(int argc, char * * argv)
                 bool rightType = false;
 
                 Machine * bestMachine = nullptr;
-                unsigned long long bestLoad = 0;
+                uint64_t bestLoad = 0;
                 for (auto & m : machines) {
                     debug("considering building on remote machine '%s'", m.storeUri);
 
@@ -130,8 +130,8 @@ static int _main(int argc, char * * argv)
                         m.mandatoryMet(requiredFeatures)) {
                         rightType = true;
                         AutoCloseFD free;
-                        unsigned long long load = 0;
+                        uint64_t load = 0;
-                        for (unsigned long long slot = 0; slot < m.maxJobs; ++slot) {
+                        for (uint64_t slot = 0; slot < m.maxJobs; ++slot) {
                             auto slotLock = openSlotLock(m, slot);
                             if (lockFile(slotLock.get(), ltWrite, false)) {
                                 if (!free) {

src/libexpr/eval.cc

@@ -1260,7 +1260,7 @@ void EvalState::callFunction(Value & fun, Value & arg, Value & v, const Pos & po
             addErrorTrace(e, lambda.pos, "while evaluating %s",
               (lambda.name.set()
                   ? "'" + (string) lambda.name + "'"
-                  : "anonymous lambdaction"));
+                  : "anonymous lambda"));
             addErrorTrace(e, pos, "from call site%s", "");
             throw;
         }

src/libexpr/flake/flake.hh

@@ -106,6 +106,6 @@ void emitTreeAttrs(
     EvalState & state,
     const fetchers::Tree & tree,
     const fetchers::Input & input,
-    Value & v);
+    Value & v, bool emptyRevFallback = false);
 
 }

src/libexpr/primops.cc

@@ -65,7 +65,7 @@ void EvalState::realiseContext(const PathSet & context)
 
     /* For performance, prefetch all substitute info. */
     StorePathSet willBuild, willSubstitute, unknown;
-    unsigned long long downloadSize, narSize;
+    uint64_t downloadSize, narSize;
     store->queryMissing(drvs, willBuild, willSubstitute, unknown, downloadSize, narSize);
 
     store->buildPaths(drvs);
@@ -1223,7 +1223,7 @@ static void prim_path(EvalState & state, const Pos & pos, Value * * args, Value
     string name;
     Value * filterFun = nullptr;
     auto method = FileIngestionMethod::Recursive;
-    Hash expectedHash(htSHA256);
+    std::optional<Hash> expectedHash;
 
     for (auto & attr : *args[0]->attrs) {
         const string & n(attr.name);

src/libexpr/primops/fetchGit.cc

@@ -1,91 +0,0 @@
-#include "primops.hh"
-#include "eval-inline.hh"
-#include "store-api.hh"
-#include "hash.hh"
-#include "fetchers.hh"
-#include "url.hh"
-
-namespace nix {
-
-static void prim_fetchGit(EvalState & state, const Pos & pos, Value * * args, Value & v)
-{
-    std::string url;
-    std::optional<std::string> ref;
-    std::optional<Hash> rev;
-    std::string name = "source";
-    bool fetchSubmodules = false;
-    PathSet context;
-
-    state.forceValue(*args[0]);
-
-    if (args[0]->type == tAttrs) {
-
-        state.forceAttrs(*args[0], pos);
-
-        for (auto & attr : *args[0]->attrs) {
-            string n(attr.name);
-            if (n == "url")
-                url = state.coerceToString(*attr.pos, *attr.value, context, false, false);
-            else if (n == "ref")
-                ref = state.forceStringNoCtx(*attr.value, *attr.pos);
-            else if (n == "rev")
-                rev = Hash(state.forceStringNoCtx(*attr.value, *attr.pos), htSHA1);
-            else if (n == "name")
-                name = state.forceStringNoCtx(*attr.value, *attr.pos);
-            else if (n == "submodules")
-                fetchSubmodules = state.forceBool(*attr.value, *attr.pos);
-            else
-                throw EvalError({
-                    .hint = hintfmt("unsupported argument '%s' to 'fetchGit'", attr.name),
-                    .errPos = *attr.pos
-                });
-        }
-
-        if (url.empty())
-            throw EvalError({
-                .hint = hintfmt("'url' argument required"),
-                .errPos = pos
-            });
-
-    } else
-        url = state.coerceToString(pos, *args[0], context, false, false);
-
-    // FIXME: git externals probably can be used to bypass the URI
-    // whitelist. Ah well.
-    state.checkURI(url);
-
-    if (evalSettings.pureEval && !rev)
-        throw Error("in pure evaluation mode, 'fetchGit' requires a Git revision");
-
-    fetchers::Attrs attrs;
-    attrs.insert_or_assign("type", "git");
-    attrs.insert_or_assign("url", url.find("://") != std::string::npos ? url : "file://" + url);
-    if (ref) attrs.insert_or_assign("ref", *ref);
-    if (rev) attrs.insert_or_assign("rev", rev->gitRev());
-    if (fetchSubmodules) attrs.insert_or_assign("submodules", fetchers::Explicit<bool>{true});
-    auto input = fetchers::Input::fromAttrs(std::move(attrs));
-
-    // FIXME: use name?
-    auto [tree, input2] = input.fetch(state.store);
-
-    state.mkAttrs(v, 8);
-    auto storePath = state.store->printStorePath(tree.storePath);
-    mkString(*state.allocAttr(v, state.sOutPath), storePath, PathSet({storePath}));
-    // Backward compatibility: set 'rev' to
-    // 0000000000000000000000000000000000000000 for a dirty tree.
-    auto rev2 = input2.getRev().value_or(Hash(htSHA1));
-    mkString(*state.allocAttr(v, state.symbols.create("rev")), rev2.gitRev());
-    mkString(*state.allocAttr(v, state.symbols.create("shortRev")), rev2.gitShortRev());
-    // Backward compatibility: set 'revCount' to 0 for a dirty tree.
-    mkInt(*state.allocAttr(v, state.symbols.create("revCount")),
-        input2.getRevCount().value_or(0));
-    mkBool(*state.allocAttr(v, state.symbols.create("submodules")), fetchSubmodules);
-    v.attrs->sort();
-
-    if (state.allowedPaths)
-        state.allowedPaths->insert(tree.actualPath);
-}
-
-static RegisterPrimOp r("fetchGit", 1, prim_fetchGit);
-
-}

src/libexpr/primops/fetchMercurial.cc

@@ -31,7 +31,7 @@ static void prim_fetchMercurial(EvalState & state, const Pos & pos, Value * * ar
                 // be both a revision or a branch/tag name.
                 auto value = state.forceStringNoCtx(*attr.value, *attr.pos);
                 if (std::regex_match(value, revRegex))
-                    rev = Hash(value, htSHA1);
+                    rev = Hash::parseAny(value, htSHA1);
                 else
                     ref = value;
             }

src/libexpr/primops/fetchTree.cc

@@ -14,7 +14,8 @@ void emitTreeAttrs(
     EvalState & state,
     const fetchers::Tree & tree,
     const fetchers::Input & input,
-    Value & v)
+    Value & v,
+    bool emptyRevFallback)
 {
     assert(input.isImmutable());
 
@@ -34,10 +35,20 @@ void emitTreeAttrs(
     if (auto rev = input.getRev()) {
         mkString(*state.allocAttr(v, state.symbols.create("rev")), rev->gitRev());
         mkString(*state.allocAttr(v, state.symbols.create("shortRev")), rev->gitShortRev());
+    } else if (emptyRevFallback) {
+        // Backwards compat for `builtins.fetchGit`: dirty repos return an empty sha1 as rev
+        auto emptyHash = Hash(htSHA1);
+        mkString(*state.allocAttr(v, state.symbols.create("rev")), emptyHash.gitRev());
+        mkString(*state.allocAttr(v, state.symbols.create("shortRev")), emptyHash.gitRev());
     }
 
+    if (input.getType() == "git")
+        mkBool(*state.allocAttr(v, state.symbols.create("submodules")), maybeGetBoolAttr(input.attrs, "submodules").value_or(false));
+
     if (auto revCount = input.getRevCount())
         mkInt(*state.allocAttr(v, state.symbols.create("revCount")), *revCount);
+    else if (emptyRevFallback)
+        mkInt(*state.allocAttr(v, state.symbols.create("revCount")), 0);
 
     if (auto lastModified = input.getLastModified()) {
         mkInt(*state.allocAttr(v, state.symbols.create("lastModified")), *lastModified);
@@ -48,10 +59,26 @@ void emitTreeAttrs(
     v.attrs->sort();
 }
 
-static void prim_fetchTree(EvalState & state, const Pos & pos, Value * * args, Value & v)
+std::string fixURI(std::string uri, EvalState &state)
 {
-    settings.requireExperimentalFeature("flakes");
+    state.checkURI(uri);
+    return uri.find("://") != std::string::npos ? uri : "file://" + uri;
+}
 
+void addURI(EvalState &state, fetchers::Attrs &attrs, Symbol name, std::string v)
+{
+    string n(name);
+    attrs.emplace(name, n == "url" ? fixURI(v, state) : v);
+}
+
+static void fetchTree(
+    EvalState &state,
+    const Pos &pos,
+    Value **args,
+    Value &v,
+    const std::optional<std::string> type,
+    bool emptyRevFallback = false
+) {
     fetchers::Input input;
     PathSet context;
 
@@ -64,8 +91,15 @@ static void prim_fetchTree(EvalState & state, const Pos & pos, Value * * args, V
 
         for (auto & attr : *args[0]->attrs) {
             state.forceValue(*attr.value);
-            if (attr.value->type == tString)
+            if (attr.value->type == tPath || attr.value->type == tString)
-                attrs.emplace(attr.name, attr.value->string.s);
+                addURI(
+                    state,
+                    attrs,
+                    attr.name,
+                    state.coerceToString(*attr.pos, *attr.value, context, false, false)
+                );
+            else if (attr.value->type == tString)
+                addURI(state, attrs, attr.name, attr.value->string.s);
             else if (attr.value->type == tBool)
                 attrs.emplace(attr.name, fetchers::Explicit<bool>{attr.value->boolean});
             else if (attr.value->type == tInt)
@@ -75,6 +109,9 @@ static void prim_fetchTree(EvalState & state, const Pos & pos, Value * * args, V
                     attr.name, showType(*attr.value));
         }
 
+        if (type)
+            attrs.emplace("type", type.value());
+
         if (!attrs.count("type"))
             throw Error({
                 .hint = hintfmt("attribute 'type' is missing in call to 'fetchTree'"),
@@ -82,8 +119,18 @@ static void prim_fetchTree(EvalState & state, const Pos & pos, Value * * args, V
             });
 
         input = fetchers::Input::fromAttrs(std::move(attrs));
-    } else
+    } else {
-        input = fetchers::Input::fromURL(state.coerceToString(pos, *args[0], context, false, false));
+        auto url = fixURI(state.coerceToString(pos, *args[0], context, false, false), state);
+
+        if (type == "git") {
+            fetchers::Attrs attrs;
+            attrs.emplace("type", "git");
+            attrs.emplace("url", url);
+            input = fetchers::Input::fromAttrs(std::move(attrs));
+        } else {
+            input = fetchers::Input::fromURL(url);
+        }
+    }
 
     if (!evalSettings.pureEval && !input.isDirect())
         input = lookupInRegistries(state.store, input).first;
@@ -96,7 +143,13 @@ static void prim_fetchTree(EvalState & state, const Pos & pos, Value * * args, V
     if (state.allowedPaths)
         state.allowedPaths->insert(tree.actualPath);
 
-    emitTreeAttrs(state, tree, input2, v);
+    emitTreeAttrs(state, tree, input2, v, emptyRevFallback);
+}
+
+static void prim_fetchTree(EvalState & state, const Pos & pos, Value * * args, Value & v)
+{
+    settings.requireExperimentalFeature("flakes");
+    fetchTree(state, pos, args, v, std::nullopt);
 }
 
 static RegisterPrimOp r("fetchTree", 1, prim_fetchTree);
@@ -178,7 +231,13 @@ static void prim_fetchTarball(EvalState & state, const Pos & pos, Value * * args
     fetch(state, pos, args, v, "fetchTarball", true, "source");
 }
 
+static void prim_fetchGit(EvalState &state, const Pos &pos, Value **args, Value &v)
+{
+    fetchTree(state, pos, args, v, "git", true);
+}
+
 static RegisterPrimOp r2("__fetchurl", 1, prim_fetchurl);
 static RegisterPrimOp r3("fetchTarball", 1, prim_fetchTarball);
+static RegisterPrimOp r4("fetchGit", 1, prim_fetchGit);
 
 }

src/libfetchers/fetchers.cc

@@ -134,7 +134,7 @@ std::pair<Tree, Input> Input::fetch(ref<Store> store) const
 
     if (auto prevNarHash = getNarHash()) {
         if (narHash != *prevNarHash)
-            throw Error("NAR hash mismatch in input '%s' (%s), expected '%s', got '%s'",
+            throw Error((unsigned int) 102, "NAR hash mismatch in input '%s' (%s), expected '%s', got '%s'",
                 to_string(), tree.actualPath, prevNarHash->to_string(SRI, true), narHash->to_string(SRI, true));
     }
 
@@ -200,9 +200,12 @@ std::string Input::getType() const
 
 std::optional<Hash> Input::getNarHash() const
 {
-    if (auto s = maybeGetStrAttr(attrs, "narHash"))
+    if (auto s = maybeGetStrAttr(attrs, "narHash")) {
-        // FIXME: require SRI hash.
+        auto hash = s->empty() ? Hash(htSHA256) : Hash::parseSRI(*s);
-        return newHashAllowEmpty(*s, htSHA256);
+        if (hash.type != htSHA256)
+            throw UsageError("narHash must use SHA-256");
+        return hash;
+    }
     return {};
 }
 
@@ -216,7 +219,7 @@ std::optional<std::string> Input::getRef() const
 std::optional<Hash> Input::getRev() const
 {
     if (auto s = maybeGetStrAttr(attrs, "rev"))
-        return Hash(*s, htSHA1);
+        return Hash::parseAny(*s, htSHA1);
     return {};
 }
 

src/libfetchers/git.cc

@@ -293,14 +293,14 @@ struct GitInputScheme : InputScheme
 
             if (!input.getRev())
                 input.attrs.insert_or_assign("rev",
-                    Hash(chomp(runProgram("git", true, { "-C", actualUrl, "rev-parse", *input.getRef() })), htSHA1).gitRev());
+                    Hash::parseAny(chomp(runProgram("git", true, { "-C", actualUrl, "rev-parse", *input.getRef() })), htSHA1).gitRev());
 
             repoDir = actualUrl;
 
         } else {
 
             if (auto res = getCache()->lookup(store, mutableAttrs)) {
-                auto rev2 = Hash(getStrAttr(res->first, "rev"), htSHA1);
+                auto rev2 = Hash::parseAny(getStrAttr(res->first, "rev"), htSHA1);
                 if (!input.getRev() || input.getRev() == rev2) {
                     input.attrs.insert_or_assign("rev", rev2.gitRev());
                     return makeResult(res->first, std::move(res->second));
@@ -370,7 +370,7 @@ struct GitInputScheme : InputScheme
             }
 
             if (!input.getRev())
-                input.attrs.insert_or_assign("rev", Hash(chomp(readFile(localRefFile)), htSHA1).gitRev());
+                input.attrs.insert_or_assign("rev", Hash::parseAny(chomp(readFile(localRefFile)), htSHA1).gitRev());
         }
 
         bool isShallow = chomp(runProgram("git", true, { "-C", repoDir, "rev-parse", "--is-shallow-repository" })) == "true";

src/libfetchers/github.cc

@@ -29,7 +29,7 @@ struct GitArchiveInputScheme : InputScheme
         if (path.size() == 2) {
         } else if (path.size() == 3) {
             if (std::regex_match(path[2], revRegex))
-                rev = Hash(path[2], htSHA1);
+                rev = Hash::parseAny(path[2], htSHA1);
             else if (std::regex_match(path[2], refRegex))
                 ref = path[2];
             else
@@ -41,7 +41,7 @@ struct GitArchiveInputScheme : InputScheme
             if (name == "rev") {
                 if (rev)
                     throw BadURL("URL '%s' contains multiple commit hashes", url.url);
-                rev = Hash(value, htSHA1);
+                rev = Hash::parseAny(value, htSHA1);
             }
             else if (name == "ref") {
                 if (!std::regex_match(value, refRegex))
@@ -191,7 +191,7 @@ struct GitHubInputScheme : GitArchiveInputScheme
             readFile(
                 store->toRealPath(
                     downloadFile(store, url, "source", false).storePath)));
-        auto rev = Hash(std::string { json["sha"] }, htSHA1);
+        auto rev = Hash::parseAny(std::string { json["sha"] }, htSHA1);
         debug("HEAD revision for '%s' is %s", url, rev.gitRev());
         return rev;
     }
@@ -235,7 +235,7 @@ struct GitLabInputScheme : GitArchiveInputScheme
             readFile(
                 store->toRealPath(
                     downloadFile(store, url, "source", false).storePath)));
-        auto rev = Hash(std::string(json[0]["id"]), htSHA1);
+        auto rev = Hash::parseAny(std::string(json[0]["id"]), htSHA1);
         debug("HEAD revision for '%s' is %s", url, rev.gitRev());
         return rev;
     }

src/libfetchers/indirect.cc

@@ -18,7 +18,7 @@ struct IndirectInputScheme : InputScheme
         if (path.size() == 1) {
         } else if (path.size() == 2) {
             if (std::regex_match(path[1], revRegex))
-                rev = Hash(path[1], htSHA1);
+                rev = Hash::parseAny(path[1], htSHA1);
             else if (std::regex_match(path[1], refRegex))
                 ref = path[1];
             else
@@ -29,7 +29,7 @@ struct IndirectInputScheme : InputScheme
             ref = path[1];
             if (!std::regex_match(path[2], revRegex))
                 throw BadURL("in flake URL '%s', '%s' is not a commit hash", url.url, path[2]);
-            rev = Hash(path[2], htSHA1);
+            rev = Hash::parseAny(path[2], htSHA1);
         } else
             throw BadURL("GitHub URL '%s' is invalid", url.url);
 

src/libfetchers/mercurial.cc

@@ -209,7 +209,7 @@ struct MercurialInputScheme : InputScheme
         });
 
         if (auto res = getCache()->lookup(store, mutableAttrs)) {
-            auto rev2 = Hash(getStrAttr(res->first, "rev"), htSHA1);
+            auto rev2 = Hash::parseAny(getStrAttr(res->first, "rev"), htSHA1);
             if (!input.getRev() || input.getRev() == rev2) {
                 input.attrs.insert_or_assign("rev", rev2.gitRev());
                 return makeResult(res->first, std::move(res->second));
@@ -252,7 +252,7 @@ struct MercurialInputScheme : InputScheme
             runProgram("hg", true, { "log", "-R", cacheDir, "-r", revOrRef, "--template", "{node} {rev} {branch}" }));
         assert(tokens.size() == 3);
 
-        input.attrs.insert_or_assign("rev", Hash(tokens[0], htSHA1).gitRev());
+        input.attrs.insert_or_assign("rev", Hash::parseAny(tokens[0], htSHA1).gitRev());
         auto revCount = std::stoull(tokens[1]);
         input.attrs.insert_or_assign("ref", tokens[2]);
 

src/libmain/shared.cc

@@ -36,7 +36,7 @@ void printGCWarning()
 
 void printMissing(ref<Store> store, const std::vector<StorePathWithOutputs> & paths, Verbosity lvl)
 {
-    unsigned long long downloadSize, narSize;
+    uint64_t downloadSize, narSize;
     StorePathSet willBuild, willSubstitute, unknown;
     store->queryMissing(paths, willBuild, willSubstitute, unknown, downloadSize, narSize);
     printMissing(store, willBuild, willSubstitute, unknown, downloadSize, narSize, lvl);
@@ -45,7 +45,7 @@ void printMissing(ref<Store> store, const std::vector<StorePathWithOutputs> & pa
 
 void printMissing(ref<Store> store, const StorePathSet & willBuild,
     const StorePathSet & willSubstitute, const StorePathSet & unknown,
-    unsigned long long downloadSize, unsigned long long narSize, Verbosity lvl)
+    uint64_t downloadSize, uint64_t narSize, Verbosity lvl)
 {
     if (!willBuild.empty()) {
         if (willBuild.size() == 1)
@@ -384,7 +384,7 @@ RunPager::~RunPager()
 }
 
 
-string showBytes(unsigned long long bytes)
+string showBytes(uint64_t bytes)
 {
     return (format("%.2f MiB") % (bytes / (1024.0 * 1024.0))).str();
 }

src/libmain/shared.hh

@@ -47,7 +47,7 @@ void printMissing(
 
 void printMissing(ref<Store> store, const StorePathSet & willBuild,
     const StorePathSet & willSubstitute, const StorePathSet & unknown,
-    unsigned long long downloadSize, unsigned long long narSize, Verbosity lvl = lvlInfo);
+    uint64_t downloadSize, uint64_t narSize, Verbosity lvl = lvlInfo);
 
 string getArg(const string & opt,
     Strings::iterator & i, const Strings::iterator & end);
@@ -110,7 +110,7 @@ extern volatile ::sig_atomic_t blockInt;
 
 /* GC helpers. */
 
-string showBytes(unsigned long long bytes);
+string showBytes(uint64_t bytes);
 
 struct GCResults;
 

src/libstore/binary-cache-store.cc

@@ -153,6 +153,8 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource
 
     auto [fdTemp, fnTemp] = createTempFile();
 
+    AutoDelete autoDelete(fnTemp);
+
     auto now1 = std::chrono::steady_clock::now();
 
     /* Read the NAR simultaneously into a CompressionSink+FileSink (to
@@ -167,6 +169,7 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource
     TeeSource teeSource(narSource, *compressionSink);
     narAccessor = makeNarAccessor(teeSource);
     compressionSink->finish();
+    fileSink.flush();
     }
 
     auto now2 = std::chrono::steady_clock::now();
@@ -280,7 +283,7 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource
     if (repair || !fileExists(narInfo->url)) {
         stats.narWrite++;
         upsertFile(narInfo->url,
-            std::make_shared<std::fstream>(fnTemp, std::ios_base::in),
+            std::make_shared<std::fstream>(fnTemp, std::ios_base::in | std::ios_base::binary),
             "application/x-nix-nar");
     } else
         stats.narWriteAverted++;

src/libstore/build.cc

@@ -297,7 +297,7 @@ public:
     GoalPtr makeDerivationGoal(const StorePath & drvPath, const StringSet & wantedOutputs, BuildMode buildMode = bmNormal);
     std::shared_ptr<DerivationGoal> makeBasicDerivationGoal(const StorePath & drvPath,
         const BasicDerivation & drv, BuildMode buildMode = bmNormal);
-    GoalPtr makeSubstitutionGoal(const StorePath & storePath, RepairFlag repair = NoRepair);
+    GoalPtr makeSubstitutionGoal(const StorePath & storePath, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
 
     /* Remove a dead goal. */
     void removeGoal(GoalPtr goal);
@@ -1206,7 +1206,7 @@ void DerivationGoal::haveDerivation()
        them. */
     if (settings.useSubstitutes && parsedDrv->substitutesAllowed())
         for (auto & i : invalidOutputs)
-            addWaitee(worker.makeSubstitutionGoal(i, buildMode == bmRepair ? Repair : NoRepair));
+            addWaitee(worker.makeSubstitutionGoal(i, buildMode == bmRepair ? Repair : NoRepair, getDerivationCA(*drv)));
 
     if (waitees.empty()) /* to prevent hang (no wake-up event) */
         outputsSubstituted();
@@ -1646,13 +1646,13 @@ void DerivationGoal::buildDone()
                So instead, check if the disk is (nearly) full now.  If
                so, we don't mark this build as a permanent failure. */
 #if HAVE_STATVFS
-            unsigned long long required = 8ULL * 1024 * 1024; // FIXME: make configurable
+            uint64_t required = 8ULL * 1024 * 1024; // FIXME: make configurable
             struct statvfs st;
             if (statvfs(worker.store.realStoreDir.c_str(), &st) == 0 &&
-                (unsigned long long) st.f_bavail * st.f_bsize < required)
+                (uint64_t) st.f_bavail * st.f_bsize < required)
                 diskFull = true;
             if (statvfs(tmpDir.c_str(), &st) == 0 &&
-                (unsigned long long) st.f_bavail * st.f_bsize < required)
+                (uint64_t) st.f_bavail * st.f_bsize < required)
                 diskFull = true;
 #endif
 
@@ -2851,7 +2851,7 @@ struct RestrictedStore : public LocalFSStore
 
     void queryMissing(const std::vector<StorePathWithOutputs> & targets,
         StorePathSet & willBuild, StorePathSet & willSubstitute, StorePathSet & unknown,
-        unsigned long long & downloadSize, unsigned long long & narSize) override
+        uint64_t & downloadSize, uint64_t & narSize) override
     {
         /* This is slightly impure since it leaks information to the
            client about what paths will be built/substituted or are
@@ -4300,6 +4300,10 @@ private:
     /* The store path that should be realised through a substitute. */
     StorePath storePath;
 
+    /* The path the substituter refers to the path as. This will be
+     * different when the stores have different names. */
+    std::optional<StorePath> subPath;
+
     /* The remaining substituters. */
     std::list<ref<Store>> subs;
 
@@ -4333,8 +4337,11 @@ private:
     typedef void (SubstitutionGoal::*GoalState)();
     GoalState state;
 
+    /* Content address for recomputing store path */
+    std::optional<ContentAddress> ca;
+
 public:
-    SubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair = NoRepair);
+    SubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
     ~SubstitutionGoal();
 
     void timedOut(Error && ex) override { abort(); };
@@ -4364,10 +4371,11 @@ public:
 };
 
 
-SubstitutionGoal::SubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair)
+SubstitutionGoal::SubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair, std::optional<ContentAddress> ca)
     : Goal(worker)
     , storePath(storePath)
     , repair(repair)
+    , ca(ca)
 {
     state = &SubstitutionGoal::init;
     name = fmt("substitution of '%s'", worker.store.printStorePath(this->storePath));
@@ -4442,14 +4450,18 @@ void SubstitutionGoal::tryNext()
     sub = subs.front();
     subs.pop_front();
 
-    if (sub->storeDir != worker.store.storeDir) {
+    if (ca) {
+        subPath = sub->makeFixedOutputPathFromCA(storePath.name(), *ca);
+        if (sub->storeDir == worker.store.storeDir)
+            assert(subPath == storePath);
+    } else if (sub->storeDir != worker.store.storeDir) {
         tryNext();
         return;
     }
 
     try {
         // FIXME: make async
-        info = sub->queryPathInfo(storePath);
+        info = sub->queryPathInfo(subPath ? *subPath : storePath);
     } catch (InvalidPath &) {
         tryNext();
         return;
@@ -4468,6 +4480,19 @@ void SubstitutionGoal::tryNext()
         throw;
     }
 
+    if (info->path != storePath) {
+        if (info->isContentAddressed(*sub) && info->references.empty()) {
+            auto info2 = std::make_shared<ValidPathInfo>(*info);
+            info2->path = storePath;
+            info = info2;
+        } else {
+            printError("asked '%s' for '%s' but got '%s'",
+                sub->getUri(), worker.store.printStorePath(storePath), sub->printStorePath(info->path));
+            tryNext();
+            return;
+        }
+    }
+
     /* Update the total expected download size. */
     auto narInfo = std::dynamic_pointer_cast<const NarInfo>(info);
 
@@ -4557,7 +4582,7 @@ void SubstitutionGoal::tryToRun()
             PushActivity pact(act.id);
 
             copyStorePath(ref<Store>(sub), ref<Store>(worker.store.shared_from_this()),
-                storePath, repair, sub->isTrusted ? NoCheckSigs : CheckSigs);
+                subPath ? *subPath : storePath, repair, sub->isTrusted ? NoCheckSigs : CheckSigs);
 
             promise.set_value();
         } catch (...) {
@@ -4690,11 +4715,11 @@ std::shared_ptr<DerivationGoal> Worker::makeBasicDerivationGoal(const StorePath
 }
 
 
-GoalPtr Worker::makeSubstitutionGoal(const StorePath & path, RepairFlag repair)
+GoalPtr Worker::makeSubstitutionGoal(const StorePath & path, RepairFlag repair, std::optional<ContentAddress> ca)
 {
     GoalPtr goal = substitutionGoals[path].lock(); // FIXME
     if (!goal) {
-        goal = std::make_shared<SubstitutionGoal>(path, *this, repair);
+        goal = std::make_shared<SubstitutionGoal>(path, *this, repair, ca);
         substitutionGoals.insert_or_assign(path, goal);
         wakeUp(goal);
     }
@@ -5062,7 +5087,7 @@ void Worker::markContentsGood(const StorePath & path)
 static void primeCache(Store & store, const std::vector<StorePathWithOutputs> & paths)
 {
     StorePathSet willBuild, willSubstitute, unknown;
-    unsigned long long downloadSize, narSize;
+    uint64_t downloadSize, narSize;
     store.queryMissing(paths, willBuild, willSubstitute, unknown, downloadSize, narSize);
 
     if (!willBuild.empty() && 0 == settings.maxBuildJobs && getMachines().empty())

src/libstore/builtins/fetchurl.cc

@@ -58,26 +58,6 @@ void builtinFetchurl(const BasicDerivation & drv, const std::string & netrcData)
         }
     };
 
-    /* We always have one output, and if it's a fixed-output derivation (as
-       checked below) it must be the only output */
-    auto & output = drv.outputs.begin()->second;
-
-    /* Try the hashed mirrors first. */
-    if (auto hash = std::get_if<DerivationOutputCAFixed>(&output.output)) {
-        if (hash->hash.method == FileIngestionMethod::Flat) {
-            for (auto hashedMirror : settings.hashedMirrors.get()) {
-                try {
-                    if (!hasSuffix(hashedMirror, "/")) hashedMirror += '/';
-                    fetch(hashedMirror + printHashType(hash->hash.hash.type) + "/" + hash->hash.hash.to_string(Base16, false));
-                    return;
-                } catch (Error & e) {
-                    debug(e.what());
-                }
-            }
-        }
-    }
-
-    /* Otherwise try the specified URL. */
     fetch(mainUrl);
 }
 

src/libstore/content-address.cc

@@ -1,4 +1,6 @@
+#include "args.hh"
 #include "content-address.hh"
+#include "split.hh"
 
 namespace nix {
 
@@ -36,38 +38,46 @@ std::string renderContentAddress(ContentAddress ca) {
 }
 
 ContentAddress parseContentAddress(std::string_view rawCa) {
-    auto prefixSeparator = rawCa.find(':');
+    auto rest = rawCa;
-    if (prefixSeparator != string::npos) {
+
-        auto prefix = string(rawCa, 0, prefixSeparator);
+    std::string_view prefix;
-        if (prefix == "text") {
+    {
-            auto hashTypeAndHash = rawCa.substr(prefixSeparator+1, string::npos);
+        auto optPrefix = splitPrefixTo(rest, ':');
-            Hash hash = Hash(string(hashTypeAndHash));
+        if (!optPrefix)
-            if (hash.type != htSHA256) {
+            throw UsageError("not a content address because it is not in the form \"<prefix>:<rest>\": %s", rawCa);
-                throw Error("parseContentAddress: the text hash should have type SHA256");
+        prefix = *optPrefix;
-            }
-            return TextHash { hash };
-        } else if (prefix == "fixed") {
-            // This has to be an inverse of makeFixedOutputCA
-            auto methodAndHash = rawCa.substr(prefixSeparator+1, string::npos);
-            if (methodAndHash.substr(0,2) == "r:") {
-                std::string_view hashRaw = methodAndHash.substr(2,string::npos);
-                return FixedOutputHash {
-                    .method = FileIngestionMethod::Recursive,
-                    .hash = Hash(string(hashRaw)),
-                };
-            } else {
-                std::string_view hashRaw = methodAndHash;
-                return FixedOutputHash {
-                    .method = FileIngestionMethod::Flat,
-                    .hash = Hash(string(hashRaw)),
-                };
-            }
-        } else {
-            throw Error("parseContentAddress: format not recognized; has to be text or fixed");
-        }
-    } else {
-        throw Error("Not a content address because it lacks an appropriate prefix");
     }
+
+    auto parseHashType_ = [&](){
+        auto hashTypeRaw = splitPrefixTo(rest, ':');
+        if (!hashTypeRaw)
+            throw UsageError("content address hash must be in form \"<algo>:<hash>\", but found: %s", rawCa);
+        HashType hashType = parseHashType(*hashTypeRaw);
+        return std::move(hashType);
+    };
+
+    // Switch on prefix
+    if (prefix == "text") {
+        // No parsing of the method, "text" only support flat.
+        HashType hashType = parseHashType_();
+        if (hashType != htSHA256)
+            throw Error("text content address hash should use %s, but instead uses %s",
+                printHashType(htSHA256), printHashType(hashType));
+        return TextHash {
+            .hash = Hash::parseNonSRIUnprefixed(rest, std::move(hashType)),
+        };
+    } else if (prefix == "fixed") {
+        // Parse method
+        auto method = FileIngestionMethod::Flat;
+        if (splitPrefix(rest, "r:"))
+            method = FileIngestionMethod::Recursive;
+        HashType hashType = parseHashType_();
+        return FixedOutputHash {
+            .method = method,
+            .hash = Hash::parseNonSRIUnprefixed(rest, std::move(hashType)),
+        };
+    } else
+        throw UsageError("content address prefix \"%s\" is unrecognized. Recogonized prefixes are \"text\" or \"fixed\"", prefix);
 };
 
 std::optional<ContentAddress> parseContentAddressOpt(std::string_view rawCaOpt) {

src/libstore/daemon.cc

@@ -86,7 +86,7 @@ struct TunnelLogger : public Logger
     }
 
     /* startWork() means that we're starting an operation for which we
-      want to send out stderr to the client. */
+       want to send out stderr to the client. */
     void startWork()
     {
         auto state(state_.lock());
@@ -579,7 +579,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         auto path = store->parseStorePath(readString(from));
         logger->startWork();
         SubstitutablePathInfos infos;
-        store->querySubstitutablePathInfos({path}, infos);
+        store->querySubstitutablePathInfos({{path, std::nullopt}}, infos);
         logger->stopWork();
         auto i = infos.find(path);
         if (i == infos.end())
@@ -595,10 +595,16 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
     }
 
     case wopQuerySubstitutablePathInfos: {
-        auto paths = readStorePaths<StorePathSet>(*store, from);
-        logger->startWork();
         SubstitutablePathInfos infos;
-        store->querySubstitutablePathInfos(paths, infos);
+        StorePathCAMap pathsMap = {};
+        if (GET_PROTOCOL_MINOR(clientVersion) < 22) {
+            auto paths = readStorePaths<StorePathSet>(*store, from);
+            for (auto & path : paths)
+                pathsMap.emplace(path, std::nullopt);
+        } else
+            pathsMap = readStorePathCAMap(*store, from);
+        logger->startWork();
+        store->querySubstitutablePathInfos(pathsMap, infos);
         logger->stopWork();
         to << infos.size();
         for (auto & i : infos) {
@@ -692,7 +698,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         auto deriver = readString(from);
         if (deriver != "")
             info.deriver = store->parseStorePath(deriver);
-        info.narHash = Hash(readString(from), htSHA256);
+        info.narHash = Hash::parseAny(readString(from), htSHA256);
         info.references = readStorePaths<StorePathSet>(*store, from);
         from >> info.registrationTime >> info.narSize >> info.ultimate;
         info.sigs = readStrings<StringSet>(from);
@@ -703,24 +709,84 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         if (!trusted)
             info.ultimate = false;
 
-        std::unique_ptr<Source> source;
+        if (GET_PROTOCOL_MINOR(clientVersion) >= 23) {
-        if (GET_PROTOCOL_MINOR(clientVersion) >= 21)
+
-            source = std::make_unique<TunnelSource>(from, to);
+            struct FramedSource : Source
-        else {
+            {
-            StringSink saved;
+                Source & from;
-            TeeSource tee { from, saved };
+                bool eof = false;
-            ParseSink ether;
+                std::vector<unsigned char> pending;
-            parseDump(ether, tee);
+                size_t pos = 0;
-            source = std::make_unique<StringSource>(std::move(*saved.s));
+
+                FramedSource(Source & from) : from(from)
+                { }
+
+                ~FramedSource()
+                {
+                    if (!eof) {
+                        while (true) {
+                            auto n = readInt(from);
+                            if (!n) break;
+                            std::vector<unsigned char> data(n);
+                            from(data.data(), n);
+                        }
+                    }
+                }
+
+                size_t read(unsigned char * data, size_t len) override
+                {
+                    if (eof) throw EndOfFile("reached end of FramedSource");
+
+                    if (pos >= pending.size()) {
+                        size_t len = readInt(from);
+                        if (!len) {
+                            eof = true;
+                            return 0;
+                        }
+                        pending = std::vector<unsigned char>(len);
+                        pos = 0;
+                        from(pending.data(), len);
+                    }
+
+                    auto n = std::min(len, pending.size() - pos);
+                    memcpy(data, pending.data() + pos, n);
+                    pos += n;
+                    return n;
+                }
+            };
+
+            logger->startWork();
+
+            {
+                FramedSource source(from);
+                store->addToStore(info, source, (RepairFlag) repair,
+                    dontCheckSigs ? NoCheckSigs : CheckSigs);
+            }
+
+            logger->stopWork();
         }
 
-        logger->startWork();
+        else {
+            std::unique_ptr<Source> source;
+            if (GET_PROTOCOL_MINOR(clientVersion) >= 21)
+                source = std::make_unique<TunnelSource>(from, to);
+            else {
+                StringSink saved;
+                TeeSource tee { from, saved };
+                ParseSink ether;
+                parseDump(ether, tee);
+                source = std::make_unique<StringSource>(std::move(*saved.s));
+            }
 
-        // FIXME: race if addToStore doesn't read source?
+            logger->startWork();
-        store->addToStore(info, *source, (RepairFlag) repair,
+
-            dontCheckSigs ? NoCheckSigs : CheckSigs);
+            // FIXME: race if addToStore doesn't read source?
+            store->addToStore(info, *source, (RepairFlag) repair,
+                dontCheckSigs ? NoCheckSigs : CheckSigs);
+
+            logger->stopWork();
+        }
 
-        logger->stopWork();
         break;
     }
 
@@ -730,7 +796,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
             targets.push_back(store->parsePathWithOutputs(s));
         logger->startWork();
         StorePathSet willBuild, willSubstitute, unknown;
-        unsigned long long downloadSize, narSize;
+        uint64_t downloadSize, narSize;
         store->queryMissing(targets, willBuild, willSubstitute, unknown, downloadSize, narSize);
         logger->stopWork();
         writeStorePaths(*store, to, willBuild);

src/libstore/derivations.cc

@@ -33,7 +33,7 @@ bool derivationIsCA(DerivationType dt) {
     };
     // Since enums can have non-variant values, but making a `default:` would
     // disable exhaustiveness warnings.
-    abort();
+    assert(false);
 }
 
 bool derivationIsFixed(DerivationType dt) {
@@ -42,7 +42,7 @@ bool derivationIsFixed(DerivationType dt) {
     case DerivationType::CAFixed: return true;
     case DerivationType::CAFloating: return false;
     };
-    abort();
+    assert(false);
 }
 
 bool derivationIsImpure(DerivationType dt) {
@@ -51,7 +51,7 @@ bool derivationIsImpure(DerivationType dt) {
     case DerivationType::CAFixed: return true;
     case DerivationType::CAFloating: return false;
     };
-    abort();
+    assert(false);
 }
 
 
@@ -159,7 +159,7 @@ static DerivationOutput parseDerivationOutput(const Store & store, std::istrings
                   .output = DerivationOutputCAFixed {
                       .hash = FixedOutputHash {
                           .method = std::move(method),
-                          .hash = Hash(hash, hashType),
+                          .hash = Hash::parseNonSRIUnprefixed(hash, hashType),
                       },
                   }
                }
@@ -556,7 +556,7 @@ static DerivationOutput readDerivationOutput(Source & in, const Store & store)
                   .output = DerivationOutputCAFixed {
                       .hash = FixedOutputHash {
                           .method = std::move(method),
-                          .hash = Hash(hash, hashType),
+                          .hash = Hash::parseNonSRIUnprefixed(hash, hashType),
                       },
                   }
                }

src/libstore/derivations.hh

@@ -14,6 +14,7 @@ namespace nix {
 
 /* Abstract syntax of derivations. */
 
+/* The traditional non-fixed-output derivation type. */
 struct DerivationOutputInputAddressed
 {
     /* Will need to become `std::optional<StorePath>` once input-addressed
@@ -21,11 +22,16 @@ struct DerivationOutputInputAddressed
     StorePath path;
 };
 
+/* Fixed-output derivations, whose output paths are content addressed
+   according to that fixed output. */
 struct DerivationOutputCAFixed
 {
     FixedOutputHash hash; /* hash used for expected hash computation */
 };
 
+/* Floating-output derivations, whose output paths are content addressed, but
+   not fixed, and so are dynamically calculated from whatever the output ends
+   up being. */
 struct DerivationOutputCAFloating
 {
     /* information used for expected hash computation */

src/libstore/gc.cc

@@ -500,7 +500,7 @@ struct LocalStore::GCState
     StorePathSet alive;
     bool gcKeepOutputs;
     bool gcKeepDerivations;
-    unsigned long long bytesInvalidated;
+    uint64_t bytesInvalidated;
     bool moveToTrash = true;
     bool shouldDelete;
     GCState(const GCOptions & options, GCResults & results)
@@ -518,7 +518,7 @@ bool LocalStore::isActiveTempFile(const GCState & state,
 
 void LocalStore::deleteGarbage(GCState & state, const Path & path)
 {
-    unsigned long long bytesFreed;
+    uint64_t bytesFreed;
     deletePath(path, bytesFreed);
     state.results.bytesFreed += bytesFreed;
 }
@@ -528,7 +528,7 @@ void LocalStore::deletePathRecursive(GCState & state, const Path & path)
 {
     checkInterrupt();
 
-    unsigned long long size = 0;
+    uint64_t size = 0;
 
     auto storePath = maybeParseStorePath(path);
     if (storePath && isValidPath(*storePath)) {
@@ -687,7 +687,7 @@ void LocalStore::removeUnusedLinks(const GCState & state)
     AutoCloseDir dir(opendir(linksDir.c_str()));
     if (!dir) throw SysError("opening directory '%1%'", linksDir);
 
-    long long actualSize = 0, unsharedSize = 0;
+    int64_t actualSize = 0, unsharedSize = 0;
 
     struct dirent * dirent;
     while (errno = 0, dirent = readdir(dir.get())) {
@@ -717,10 +717,10 @@ void LocalStore::removeUnusedLinks(const GCState & state)
     struct stat st;
     if (stat(linksDir.c_str(), &st) == -1)
         throw SysError("statting '%1%'", linksDir);
-    long long overhead = st.st_blocks * 512ULL;
+    auto overhead = st.st_blocks * 512ULL;
 
-    printInfo(format("note: currently hard linking saves %.2f MiB")
+    printInfo("note: currently hard linking saves %.2f MiB",
-        % ((unsharedSize - actualSize - overhead) / (1024.0 * 1024.0)));
+        ((unsharedSize - actualSize - overhead) / (1024.0 * 1024.0)));
 }
 
 

src/libstore/globals.hh

@@ -335,9 +335,6 @@ public:
         "setuid/setgid bits or with file capabilities."};
 #endif
 
-    Setting<Strings> hashedMirrors{this, {"http://tarballs.nixos.org/"}, "hashed-mirrors",
-        "A list of servers used by builtins.fetchurl to fetch files by hash."};
-
     Setting<uint64_t> minFree{this, 0, "min-free",
         "Automatically run the garbage collector when free disk space drops below the specified amount."};
 

src/libstore/legacy-ssh-store.cc

@@ -113,7 +113,7 @@ struct LegacySSHStore : public Store
 
             if (GET_PROTOCOL_MINOR(conn->remoteVersion) >= 4) {
                 auto s = readString(conn->from);
-                info->narHash = s.empty() ? std::optional<Hash>{} : Hash{s};
+                info->narHash = s.empty() ? std::optional<Hash>{} : Hash::parseAnyPrefixed(s);
                 info->ca = parseContentAddressOpt(readString(conn->from));
                 info->sigs = readStrings<StringSet>(conn->from);
             }

src/libstore/local-store.cc

@@ -655,7 +655,7 @@ void LocalStore::queryPathInfoUncached(const StorePath & path,
             info->id = useQueryPathInfo.getInt(0);
 
             try {
-                info->narHash = Hash(useQueryPathInfo.getStr(1));
+                info->narHash = Hash::parseAnyPrefixed(useQueryPathInfo.getStr(1));
             } catch (BadHash & e) {
                 throw Error("in valid-path entry for '%s': %s", printStorePath(path), e.what());
             }
@@ -854,20 +854,32 @@ StorePathSet LocalStore::querySubstitutablePaths(const StorePathSet & paths)
 }
 
 
-void LocalStore::querySubstitutablePathInfos(const StorePathSet & paths,
+void LocalStore::querySubstitutablePathInfos(const StorePathCAMap & paths, SubstitutablePathInfos & infos)
-    SubstitutablePathInfos & infos)
 {
     if (!settings.useSubstitutes) return;
     for (auto & sub : getDefaultSubstituters()) {
-        if (sub->storeDir != storeDir) continue;
         for (auto & path : paths) {
-            if (infos.count(path)) continue;
+            auto subPath(path.first);
-            debug("checking substituter '%s' for path '%s'", sub->getUri(), printStorePath(path));
+
+            // recompute store path so that we can use a different store root
+            if (path.second) {
+                subPath = makeFixedOutputPathFromCA(path.first.name(), *path.second);
+                if (sub->storeDir == storeDir)
+                    assert(subPath == path.first);
+                if (subPath != path.first)
+                    debug("replaced path '%s' with '%s' for substituter '%s'", printStorePath(path.first), sub->printStorePath(subPath), sub->getUri());
+            } else if (sub->storeDir != storeDir) continue;
+
+            debug("checking substituter '%s' for path '%s'", sub->getUri(), sub->printStorePath(subPath));
             try {
-                auto info = sub->queryPathInfo(path);
+                auto info = sub->queryPathInfo(subPath);
+
+                if (sub->storeDir != storeDir && !(info->isContentAddressed(*sub) && info->references.empty()))
+                    continue;
+
                 auto narInfo = std::dynamic_pointer_cast<const NarInfo>(
                     std::shared_ptr<const ValidPathInfo>(info));
-                infos.insert_or_assign(path, SubstitutablePathInfo{
+                infos.insert_or_assign(path.first, SubstitutablePathInfo{
                     info->deriver,
                     info->references,
                     narInfo ? narInfo->fileSize : 0,
@@ -1041,20 +1053,6 @@ void LocalStore::addToStore(const ValidPathInfo & info, Source & source,
 }
 
 
-StorePath LocalStore::addToStore(const string & name, const Path & _srcPath,
-    FileIngestionMethod method, HashType hashAlgo, PathFilter & filter, RepairFlag repair)
-{
-    Path srcPath(absPath(_srcPath));
-    auto source = sinkToSource([&](Sink & sink) {
-        if (method == FileIngestionMethod::Recursive)
-            dumpPath(srcPath, sink, filter);
-        else
-            readFile(srcPath, sink);
-    });
-    return addToStoreFromDump(*source, name, method, hashAlgo, repair);
-}
-
-
 StorePath LocalStore::addToStoreFromDump(Source & source0, const string & name,
     FileIngestionMethod method, HashType hashAlgo, RepairFlag repair)
 {

src/libstore/local-store.hh

@@ -29,8 +29,8 @@ struct Derivation;
 struct OptimiseStats
 {
     unsigned long filesLinked = 0;
-    unsigned long long bytesFreed = 0;
+    uint64_t bytesFreed = 0;
-    unsigned long long blocksFreed = 0;
+    uint64_t blocksFreed = 0;
 };
 
 
@@ -139,22 +139,14 @@ public:
 
     StorePathSet querySubstitutablePaths(const StorePathSet & paths) override;
 
-    void querySubstitutablePathInfos(const StorePathSet & paths,
+    void querySubstitutablePathInfos(const StorePathCAMap & paths,
         SubstitutablePathInfos & infos) override;
 
     void addToStore(const ValidPathInfo & info, Source & source,
         RepairFlag repair, CheckSigsFlag checkSigs) override;
 
-    StorePath addToStore(const string & name, const Path & srcPath,
-        FileIngestionMethod method, HashType hashAlgo,
-        PathFilter & filter, RepairFlag repair) override;
-
-    /* Like addToStore(), but the contents of the path are contained
-       in `dump', which is either a NAR serialisation (if recursive ==
-       true) or simply the contents of a regular file (if recursive ==
-       false). */
     StorePath addToStoreFromDump(Source & dump, const string & name,
-        FileIngestionMethod method = FileIngestionMethod::Recursive, HashType hashAlgo = htSHA256, RepairFlag repair = NoRepair) override;
+        FileIngestionMethod method, HashType hashAlgo, RepairFlag repair) override;
 
     StorePath addTextToStore(const string & name, const string & s,
         const StorePathSet & references, RepairFlag repair) override;

src/libstore/misc.cc

@@ -4,6 +4,7 @@
 #include "local-store.hh"
 #include "store-api.hh"
 #include "thread-pool.hh"
+#include "topo-sort.hh"
 
 
 namespace nix {
@@ -108,9 +109,19 @@ void Store::computeFSClosure(const StorePath & startPath,
 }
 
 
+std::optional<ContentAddress> getDerivationCA(const BasicDerivation & drv)
+{
+    auto out = drv.outputs.find("out");
+    if (out != drv.outputs.end()) {
+        if (auto v = std::get_if<DerivationOutputCAFixed>(&out->second.output))
+            return v->hash;
+    }
+    return std::nullopt;
+}
+
 void Store::queryMissing(const std::vector<StorePathWithOutputs> & targets,
     StorePathSet & willBuild_, StorePathSet & willSubstitute_, StorePathSet & unknown_,
-    unsigned long long & downloadSize_, unsigned long long & narSize_)
+    uint64_t & downloadSize_, uint64_t & narSize_)
 {
     Activity act(*logger, lvlDebug, actUnknown, "querying info about missing paths");
 
@@ -122,8 +133,8 @@ void Store::queryMissing(const std::vector<StorePathWithOutputs> & targets,
     {
         std::unordered_set<std::string> done;
         StorePathSet & unknown, & willSubstitute, & willBuild;
-        unsigned long long & downloadSize;
+        uint64_t & downloadSize;
-        unsigned long long & narSize;
+        uint64_t & narSize;
     };
 
     struct DrvState
@@ -157,7 +168,7 @@ void Store::queryMissing(const std::vector<StorePathWithOutputs> & targets,
         auto outPath = parseStorePath(outPathS);
 
         SubstitutablePathInfos infos;
-        querySubstitutablePathInfos({outPath}, infos);
+        querySubstitutablePathInfos({{outPath, getDerivationCA(*drv)}}, infos);
 
         if (infos.empty()) {
             drvState_->lock()->done = true;
@@ -214,7 +225,7 @@ void Store::queryMissing(const std::vector<StorePathWithOutputs> & targets,
             if (isValidPath(path.path)) return;
 
             SubstitutablePathInfos infos;
-            querySubstitutablePathInfos({path.path}, infos);
+            querySubstitutablePathInfos({{path.path, std::nullopt}}, infos);
 
             if (infos.empty()) {
                 auto state(state_.lock());
@@ -246,41 +257,21 @@ void Store::queryMissing(const std::vector<StorePathWithOutputs> & targets,
 
 StorePaths Store::topoSortPaths(const StorePathSet & paths)
 {
-    StorePaths sorted;
+    return topoSort(paths,
-    StorePathSet visited, parents;
+        {[&](const StorePath & path) {
-
+            StorePathSet references;
-    std::function<void(const StorePath & path, const StorePath * parent)> dfsVisit;
+            try {
-
+                references = queryPathInfo(path)->references;
-    dfsVisit = [&](const StorePath & path, const StorePath * parent) {
+            } catch (InvalidPath &) {
-        if (parents.count(path))
+            }
-            throw BuildError("cycle detected in the references of '%s' from '%s'",
+            return references;
-                printStorePath(path), printStorePath(*parent));
+        }},
-
+        {[&](const StorePath & path, const StorePath & parent) {
-        if (!visited.insert(path).second) return;
+            return BuildError(
-        parents.insert(path);
+                "cycle detected in the references of '%s' from '%s'",
-
+                printStorePath(path),
-        StorePathSet references;
+                printStorePath(parent));
-        try {
+        }});
-            references = queryPathInfo(path)->references;
-        } catch (InvalidPath &) {
-        }
-
-        for (auto & i : references)
-            /* Don't traverse into paths that don't exist.  That can
-               happen due to substitutes for non-existent paths. */
-            if (i != path && paths.count(i))
-                dfsVisit(i, &path);
-
-        sorted.push_back(path);
-        parents.erase(path);
-    };
-
-    for (auto & i : paths)
-        dfsVisit(i, nullptr);
-
-    std::reverse(sorted.begin(), sorted.end());
-
-    return sorted;
 }
 
 

src/libstore/nar-accessor.cc

@@ -79,14 +79,14 @@ struct NarAccessor : public FSAccessor
             parents.top()->isExecutable = true;
         }
 
-        void preallocateContents(unsigned long long size) override
+        void preallocateContents(uint64_t size) override
         {
             assert(size <= std::numeric_limits<uint64_t>::max());
             parents.top()->size = (uint64_t) size;
             parents.top()->start = pos;
         }
 
-        void receiveContents(unsigned char * data, unsigned int len) override
+        void receiveContents(unsigned char * data, size_t len) override
         { }
 
         void createSymlink(const Path & path, const string & target) override

src/libstore/nar-info-disk-cache.cc

@@ -193,9 +193,9 @@ public:
             narInfo->url = queryNAR.getStr(2);
             narInfo->compression = queryNAR.getStr(3);
             if (!queryNAR.isNull(4))
-                narInfo->fileHash = Hash(queryNAR.getStr(4));
+                narInfo->fileHash = Hash::parseAnyPrefixed(queryNAR.getStr(4));
             narInfo->fileSize = queryNAR.getInt(5);
-            narInfo->narHash = Hash(queryNAR.getStr(6));
+            narInfo->narHash = Hash::parseAnyPrefixed(queryNAR.getStr(6));
             narInfo->narSize = queryNAR.getInt(7);
             for (auto & r : tokenizeString<Strings>(queryNAR.getStr(8), " "))
                 narInfo->references.insert(StorePath(r));

src/libstore/nar-info.cc

@@ -12,7 +12,7 @@ NarInfo::NarInfo(const Store & store, const std::string & s, const std::string &
 
     auto parseHashField = [&](const string & s) {
         try {
-            return Hash(s);
+            return Hash::parseAnyPrefixed(s);
         } catch (BadHash &) {
             throw corrupt();
         }

src/libstore/optimise-store.cc

@@ -282,7 +282,7 @@ void LocalStore::optimiseStore(OptimiseStats & stats)
     }
 }
 
-static string showBytes(unsigned long long bytes)
+static string showBytes(uint64_t bytes)
 {
     return (format("%.2f MiB") % (bytes / (1024.0 * 1024.0))).str();
 }

src/libstore/path-info.hh

@@ -0,0 +1,111 @@
+#pragma once
+
+#include "path.hh"
+#include "hash.hh"
+#include "content-address.hh"
+
+#include <string>
+#include <optional>
+
+namespace nix {
+
+
+class Store;
+
+
+struct SubstitutablePathInfo
+{
+    std::optional<StorePath> deriver;
+    StorePathSet references;
+    uint64_t downloadSize; /* 0 = unknown or inapplicable */
+    uint64_t narSize; /* 0 = unknown */
+};
+
+typedef std::map<StorePath, SubstitutablePathInfo> SubstitutablePathInfos;
+
+
+struct ValidPathInfo
+{
+    StorePath path;
+    std::optional<StorePath> deriver;
+    // TODO document this
+    std::optional<Hash> narHash;
+    StorePathSet references;
+    time_t registrationTime = 0;
+    uint64_t narSize = 0; // 0 = unknown
+    uint64_t id; // internal use only
+
+    /* Whether the path is ultimately trusted, that is, it's a
+       derivation output that was built locally. */
+    bool ultimate = false;
+
+    StringSet sigs; // note: not necessarily verified
+
+    /* If non-empty, an assertion that the path is content-addressed,
+       i.e., that the store path is computed from a cryptographic hash
+       of the contents of the path, plus some other bits of data like
+       the "name" part of the path. Such a path doesn't need
+       signatures, since we don't have to trust anybody's claim that
+       the path is the output of a particular derivation. (In the
+       extensional store model, we have to trust that the *contents*
+       of an output path of a derivation were actually produced by
+       that derivation. In the intensional model, we have to trust
+       that a particular output path was produced by a derivation; the
+       path then implies the contents.)
+
+       Ideally, the content-addressability assertion would just be a Boolean,
+       and the store path would be computed from the name component, ‘narHash’
+       and ‘references’. However, we support many types of content addresses.
+    */
+    std::optional<ContentAddress> ca;
+
+    bool operator == (const ValidPathInfo & i) const
+    {
+        return
+            path == i.path
+            && narHash == i.narHash
+            && references == i.references;
+    }
+
+    /* Return a fingerprint of the store path to be used in binary
+       cache signatures. It contains the store path, the base-32
+       SHA-256 hash of the NAR serialisation of the path, the size of
+       the NAR, and the sorted references. The size field is strictly
+       speaking superfluous, but might prevent endless/excessive data
+       attacks. */
+    std::string fingerprint(const Store & store) const;
+
+    void sign(const Store & store, const SecretKey & secretKey);
+
+    /* Return true iff the path is verifiably content-addressed. */
+    bool isContentAddressed(const Store & store) const;
+
+    /* Functions to view references + hasSelfReference as one set, mainly for
+       compatibility's sake. */
+    StorePathSet referencesPossiblyToSelf() const;
+    void insertReferencePossiblyToSelf(StorePath && ref);
+    void setReferencesPossiblyToSelf(StorePathSet && refs);
+
+    static const size_t maxSigs = std::numeric_limits<size_t>::max();
+
+    /* Return the number of signatures on this .narinfo that were
+       produced by one of the specified keys, or maxSigs if the path
+       is content-addressed. */
+    size_t checkSignatures(const Store & store, const PublicKeys & publicKeys) const;
+
+    /* Verify a single signature. */
+    bool checkSignature(const Store & store, const PublicKeys & publicKeys, const std::string & sig) const;
+
+    Strings shortRefs() const;
+
+    ValidPathInfo(const ValidPathInfo & other) = default;
+
+    ValidPathInfo(StorePath && path) : path(std::move(path)) { };
+    ValidPathInfo(const StorePath & path) : path(path) { };
+
+    virtual ~ValidPathInfo() { }
+};
+
+typedef list<ValidPathInfo> ValidPathInfos;
+
+}

src/libstore/path.hh

@@ -64,6 +64,8 @@ typedef std::set<StorePath> StorePathSet;
 typedef std::vector<StorePath> StorePaths;
 typedef std::map<string, StorePath> OutputPathMap;
 
+typedef std::map<StorePath, std::optional<ContentAddress>> StorePathCAMap;
+
 /* Extension of derivations in the Nix store. */
 const std::string drvExtension = ".drv";
 

src/libstore/remote-store.cc

@@ -39,6 +39,24 @@ void writeStorePaths(const Store & store, Sink & out, const StorePathSet & paths
         out << store.printStorePath(i);
 }
 
+StorePathCAMap readStorePathCAMap(const Store & store, Source & from)
+{
+    StorePathCAMap paths;
+    auto count = readNum<size_t>(from);
+    while (count--)
+        paths.insert_or_assign(store.parseStorePath(readString(from)), parseContentAddressOpt(readString(from)));
+    return paths;
+}
+
+void writeStorePathCAMap(const Store & store, Sink & out, const StorePathCAMap & paths)
+{
+    out << paths.size();
+    for (auto & i : paths) {
+        out << store.printStorePath(i.first);
+        out << renderContentAddress(i.second);
+    }
+}
+
 std::map<string, StorePath> readOutputPathMap(const Store & store, Source & from)
 {
     std::map<string, StorePath> pathMap;
@@ -332,18 +350,17 @@ StorePathSet RemoteStore::querySubstitutablePaths(const StorePathSet & paths)
 }
 
 
-void RemoteStore::querySubstitutablePathInfos(const StorePathSet & paths,
+void RemoteStore::querySubstitutablePathInfos(const StorePathCAMap & pathsMap, SubstitutablePathInfos & infos)
-    SubstitutablePathInfos & infos)
 {
-    if (paths.empty()) return;
+    if (pathsMap.empty()) return;
 
     auto conn(getConnection());
 
     if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 12) {
 
-        for (auto & i : paths) {
+        for (auto & i : pathsMap) {
             SubstitutablePathInfo info;
-            conn->to << wopQuerySubstitutablePathInfo << printStorePath(i);
+            conn->to << wopQuerySubstitutablePathInfo << printStorePath(i.first);
             conn.processStderr();
             unsigned int reply = readInt(conn->from);
             if (reply == 0) continue;
@@ -353,13 +370,19 @@ void RemoteStore::querySubstitutablePathInfos(const StorePathSet & paths,
             info.references = readStorePaths<StorePathSet>(*this, conn->from);
             info.downloadSize = readLongLong(conn->from);
             info.narSize = readLongLong(conn->from);
-            infos.insert_or_assign(i, std::move(info));
+            infos.insert_or_assign(i.first, std::move(info));
         }
 
     } else {
 
         conn->to << wopQuerySubstitutablePathInfos;
-        writeStorePaths(*this, conn->to, paths);
+        if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 22) {
+            StorePathSet paths;
+            for (auto & path : pathsMap)
+                paths.insert(path.first);
+            writeStorePaths(*this, conn->to, paths);
+        } else
+            writeStorePathCAMap(*this, conn->to, pathsMap);
         conn.processStderr();
         size_t count = readNum<size_t>(conn->from);
         for (size_t n = 0; n < count; n++) {
@@ -399,7 +422,7 @@ void RemoteStore::queryPathInfoUncached(const StorePath & path,
             info = std::make_shared<ValidPathInfo>(StorePath(path));
             auto deriver = readString(conn->from);
             if (deriver != "") info->deriver = parseStorePath(deriver);
-            info->narHash = Hash(readString(conn->from), htSHA256);
+            info->narHash = Hash::parseAny(readString(conn->from), htSHA256);
             info->references = readStorePaths<StorePathSet>(*this, conn->from);
             conn->from >> info->registrationTime >> info->narSize;
             if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 16) {
@@ -503,9 +526,84 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
         conn->to << info.registrationTime << info.narSize
                  << info.ultimate << info.sigs << renderContentAddress(info.ca)
                  << repair << !checkSigs;
-        bool tunnel = GET_PROTOCOL_MINOR(conn->daemonVersion) >= 21;
+
-        if (!tunnel) copyNAR(source, conn->to);
+        if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 23) {
-        conn.processStderr(0, tunnel ? &source : nullptr);
+
+            std::exception_ptr ex;
+
+            struct FramedSink : BufferedSink
+            {
+                ConnectionHandle & conn;
+                std::exception_ptr & ex;
+
+                FramedSink(ConnectionHandle & conn, std::exception_ptr & ex) : conn(conn), ex(ex)
+                { }
+
+                ~FramedSink()
+                {
+                    try {
+                        conn->to << 0;
+                        conn->to.flush();
+                    } catch (...) {
+                        ignoreException();
+                    }
+                }
+
+                void write(const unsigned char * data, size_t len) override
+                {
+                    /* Don't send more data if the remote has
+                       encountered an error. */
+                    if (ex) {
+                        auto ex2 = ex;
+                        ex = nullptr;
+                        std::rethrow_exception(ex2);
+                    }
+                    conn->to << len;
+                    conn->to(data, len);
+                };
+            };
+
+            /* Handle log messages / exceptions from the remote on a
+               separate thread. */
+            std::thread stderrThread([&]()
+            {
+                try {
+                    conn.processStderr();
+                } catch (...) {
+                    ex = std::current_exception();
+                }
+            });
+
+            Finally joinStderrThread([&]()
+            {
+                if (stderrThread.joinable()) {
+                    stderrThread.join();
+                    if (ex) {
+                        try {
+                            std::rethrow_exception(ex);
+                        } catch (...) {
+                            ignoreException();
+                        }
+                    }
+                }
+            });
+
+            {
+                FramedSink sink(conn, ex);
+                copyNAR(source, sink);
+                sink.flush();
+            }
+
+            stderrThread.join();
+            if (ex)
+                std::rethrow_exception(ex);
+
+        } else if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 21) {
+            conn.processStderr(0, &source);
+        } else {
+            copyNAR(source, conn->to);
+            conn.processStderr(0, nullptr);
+        }
     }
 }
 
@@ -707,7 +805,7 @@ void RemoteStore::addSignatures(const StorePath & storePath, const StringSet & s
 
 void RemoteStore::queryMissing(const std::vector<StorePathWithOutputs> & targets,
     StorePathSet & willBuild, StorePathSet & willSubstitute, StorePathSet & unknown,
-    unsigned long long & downloadSize, unsigned long long & narSize)
+    uint64_t & downloadSize, uint64_t & narSize)
 {
     {
         auto conn(getConnection());

src/libstore/remote-store.hh

@@ -56,7 +56,7 @@ public:
 
     StorePathSet querySubstitutablePaths(const StorePathSet & paths) override;
 
-    void querySubstitutablePathInfos(const StorePathSet & paths,
+    void querySubstitutablePathInfos(const StorePathCAMap & paths,
         SubstitutablePathInfos & infos) override;
 
     void addToStore(const ValidPathInfo & info, Source & nar,
@@ -94,7 +94,7 @@ public:
 
     void queryMissing(const std::vector<StorePathWithOutputs> & targets,
         StorePathSet & willBuild, StorePathSet & willSubstitute, StorePathSet & unknown,
-        unsigned long long & downloadSize, unsigned long long & narSize) override;
+        uint64_t & downloadSize, uint64_t & narSize) override;
 
     void connect() override;
 

src/libstore/s3-binary-cache-store.cc

@@ -266,6 +266,10 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
         const std::string & mimeType,
         const std::string & contentEncoding)
     {
+        istream->seekg(0, istream->end);
+        auto size = istream->tellg();
+        istream->seekg(0, istream->beg);
+
         auto maxThreads = std::thread::hardware_concurrency();
 
         static std::shared_ptr<Aws::Utils::Threading::PooledThreadExecutor>
@@ -343,13 +347,11 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
             std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1)
                 .count();
 
-        auto size = istream->tellg();
-
         printInfo("uploaded 's3://%s/%s' (%d bytes) in %d ms",
             bucketName, path, size, duration);
 
         stats.putTimeMs += duration;
-        stats.putBytes += size;
+        stats.putBytes += std::max(size, (decltype(size)) 0);
         stats.put++;
     }
 

src/libstore/store-api.cc

@@ -193,6 +193,19 @@ StorePath Store::makeFixedOutputPath(
     }
 }
 
+StorePath Store::makeFixedOutputPathFromCA(std::string_view name, ContentAddress ca,
+    const StorePathSet & references, bool hasSelfReference) const
+{
+    // New template
+    return std::visit(overloaded {
+        [&](TextHash th) {
+            return makeTextPath(name, th.hash, references);
+        },
+        [&](FixedOutputHash fsh) {
+            return makeFixedOutputPath(fsh.method, fsh.hash, name, references, hasSelfReference);
+        }
+    }, ca);
+}
 
 StorePath Store::makeTextPath(std::string_view name, const Hash & hash,
     const StorePathSet & references) const
@@ -222,6 +235,20 @@ StorePath Store::computeStorePathForText(const string & name, const string & s,
 }
 
 
+StorePath Store::addToStore(const string & name, const Path & _srcPath,
+    FileIngestionMethod method, HashType hashAlgo, PathFilter & filter, RepairFlag repair)
+{
+    Path srcPath(absPath(_srcPath));
+    auto source = sinkToSource([&](Sink & sink) {
+        if (method == FileIngestionMethod::Recursive)
+            dumpPath(srcPath, sink, filter);
+        else
+            readFile(srcPath, sink);
+    });
+    return addToStoreFromDump(*source, name, method, hashAlgo, repair);
+}
+
+
 /*
 The aim of this function is to compute in one pass the correct ValidPathInfo for
 the files that we are trying to add to the store. To accomplish that in one
@@ -689,6 +716,15 @@ void copyStorePath(ref<Store> srcStore, ref<Store> dstStore,
 
     uint64_t total = 0;
 
+    // recompute store path on the chance dstStore does it differently
+    if (info->ca && info->references.empty()) {
+        auto info2 = make_ref<ValidPathInfo>(*info);
+        info2->path = dstStore->makeFixedOutputPathFromCA(info->path.name(), *info->ca);
+        if (dstStore->storeDir == srcStore->storeDir)
+            assert(info->path == info2->path);
+        info = info2;
+    }
+
     if (!info->narHash) {
         StringSink sink;
         srcStore->narFromPath({storePath}, sink);
@@ -724,16 +760,20 @@ void copyStorePath(ref<Store> srcStore, ref<Store> dstStore,
 }
 
 
-void copyPaths(ref<Store> srcStore, ref<Store> dstStore, const StorePathSet & storePaths,
+std::map<StorePath, StorePath> copyPaths(ref<Store> srcStore, ref<Store> dstStore, const StorePathSet & storePaths,
     RepairFlag repair, CheckSigsFlag checkSigs, SubstituteFlag substitute)
 {
     auto valid = dstStore->queryValidPaths(storePaths, substitute);
 
-    PathSet missing;
+    StorePathSet missing;
     for (auto & path : storePaths)
-        if (!valid.count(path)) missing.insert(srcStore->printStorePath(path));
+        if (!valid.count(path)) missing.insert(path);
 
-    if (missing.empty()) return;
+    std::map<StorePath, StorePath> pathsMap;
+    for (auto & path : storePaths)
+        pathsMap.insert_or_assign(path, path);
+
+    if (missing.empty()) return pathsMap;
 
     Activity act(*logger, lvlInfo, actCopyPaths, fmt("copying %d paths", missing.size()));
 
@@ -748,30 +788,49 @@ void copyPaths(ref<Store> srcStore, ref<Store> dstStore, const StorePathSet & st
 
     ThreadPool pool;
 
-    processGraph<Path>(pool,
+    processGraph<StorePath>(pool,
-        PathSet(missing.begin(), missing.end()),
+        StorePathSet(missing.begin(), missing.end()),
 
-        [&](const Path & storePath) {
+        [&](const StorePath & storePath) {
-            if (dstStore->isValidPath(dstStore->parseStorePath(storePath))) {
+            auto info = srcStore->queryPathInfo(storePath);
+            auto storePathForDst = storePath;
+            if (info->ca && info->references.empty()) {
+                storePathForDst = dstStore->makeFixedOutputPathFromCA(storePath.name(), *info->ca);
+                if (dstStore->storeDir == srcStore->storeDir)
+                    assert(storePathForDst == storePath);
+                if (storePathForDst != storePath)
+                    debug("replaced path '%s' to '%s' for substituter '%s'", srcStore->printStorePath(storePath), dstStore->printStorePath(storePathForDst), dstStore->getUri());
+            }
+            pathsMap.insert_or_assign(storePath, storePathForDst);
+
+            if (dstStore->isValidPath(storePath)) {
                 nrDone++;
                 showProgress();
-                return PathSet();
+                return StorePathSet();
             }
 
-            auto info = srcStore->queryPathInfo(srcStore->parseStorePath(storePath));
-
             bytesExpected += info->narSize;
             act.setExpected(actCopyPath, bytesExpected);
 
-            return srcStore->printStorePathSet(info->references);
+            return info->references;
         },
 
-        [&](const Path & storePathS) {
+        [&](const StorePath & storePath) {
             checkInterrupt();
 
-            auto storePath = dstStore->parseStorePath(storePathS);
+            auto info = srcStore->queryPathInfo(storePath);
 
-            if (!dstStore->isValidPath(storePath)) {
+            auto storePathForDst = storePath;
+            if (info->ca && info->references.empty()) {
+                storePathForDst = dstStore->makeFixedOutputPathFromCA(storePath.name(), *info->ca);
+                if (dstStore->storeDir == srcStore->storeDir)
+                    assert(storePathForDst == storePath);
+                if (storePathForDst != storePath)
+                    debug("replaced path '%s' to '%s' for substituter '%s'", srcStore->printStorePath(storePath), dstStore->printStorePath(storePathForDst), dstStore->getUri());
+            }
+            pathsMap.insert_or_assign(storePath, storePathForDst);
+
+            if (!dstStore->isValidPath(storePathForDst)) {
                 MaintainCount<decltype(nrRunning)> mc(nrRunning);
                 showProgress();
                 try {
@@ -780,7 +839,7 @@ void copyPaths(ref<Store> srcStore, ref<Store> dstStore, const StorePathSet & st
                     nrFailed++;
                     if (!settings.keepGoing)
                         throw e;
-                    logger->log(lvlError, fmt("could not copy %s: %s", storePathS, e.what()));
+                    logger->log(lvlError, fmt("could not copy %s: %s", dstStore->printStorePath(storePath), e.what()));
                     showProgress();
                     return;
                 }
@@ -789,6 +848,8 @@ void copyPaths(ref<Store> srcStore, ref<Store> dstStore, const StorePathSet & st
             nrDone++;
             showProgress();
         });
+
+    return pathsMap;
 }
 
 
@@ -811,7 +872,7 @@ std::optional<ValidPathInfo> decodeValidPathInfo(const Store & store, std::istre
     if (hashGiven) {
         string s;
         getline(str, s);
-        info.narHash = Hash(s, htSHA256);
+        info.narHash = Hash::parseAny(s, htSHA256);
         getline(str, s);
         if (!string2Int(s, info.narSize)) throw Error("number expected");
     }

src/libstore/store-api.hh

@@ -10,6 +10,7 @@
 #include "globals.hh"
 #include "config.hh"
 #include "derivations.hh"
+#include "path-info.hh"
 
 #include <atomic>
 #include <limits>
@@ -85,7 +86,7 @@ struct GCOptions
     StorePathSet pathsToDelete;
 
     /* Stop after at least `maxFreed' bytes have been freed. */
-    unsigned long long maxFreed{std::numeric_limits<unsigned long long>::max()};
+    uint64_t maxFreed{std::numeric_limits<uint64_t>::max()};
 };
 
 
@@ -97,99 +98,10 @@ struct GCResults
 
     /* For `gcReturnDead', `gcDeleteDead' and `gcDeleteSpecific', the
        number of bytes that would be or was freed. */
-    unsigned long long bytesFreed = 0;
+    uint64_t bytesFreed = 0;
 };
 
 
-struct SubstitutablePathInfo
-{
-    std::optional<StorePath> deriver;
-    StorePathSet references;
-    unsigned long long downloadSize; /* 0 = unknown or inapplicable */
-    unsigned long long narSize; /* 0 = unknown */
-};
-
-typedef std::map<StorePath, SubstitutablePathInfo> SubstitutablePathInfos;
-
-struct ValidPathInfo
-{
-    StorePath path;
-    std::optional<StorePath> deriver;
-    // TODO document this
-    std::optional<Hash> narHash;
-    StorePathSet references;
-    time_t registrationTime = 0;
-    uint64_t narSize = 0; // 0 = unknown
-    uint64_t id; // internal use only
-
-    /* Whether the path is ultimately trusted, that is, it's a
-       derivation output that was built locally. */
-    bool ultimate = false;
-
-    StringSet sigs; // note: not necessarily verified
-
-    /* If non-empty, an assertion that the path is content-addressed,
-       i.e., that the store path is computed from a cryptographic hash
-       of the contents of the path, plus some other bits of data like
-       the "name" part of the path. Such a path doesn't need
-       signatures, since we don't have to trust anybody's claim that
-       the path is the output of a particular derivation. (In the
-       extensional store model, we have to trust that the *contents*
-       of an output path of a derivation were actually produced by
-       that derivation. In the intensional model, we have to trust
-       that a particular output path was produced by a derivation; the
-       path then implies the contents.)
-
-       Ideally, the content-addressability assertion would just be a Boolean,
-       and the store path would be computed from the name component, ‘narHash’
-       and ‘references’. However, we support many types of content addresses.
-    */
-    std::optional<ContentAddress> ca;
-
-    bool operator == (const ValidPathInfo & i) const
-    {
-        return
-            path == i.path
-            && narHash == i.narHash
-            && references == i.references;
-    }
-
-    /* Return a fingerprint of the store path to be used in binary
-       cache signatures. It contains the store path, the base-32
-       SHA-256 hash of the NAR serialisation of the path, the size of
-       the NAR, and the sorted references. The size field is strictly
-       speaking superfluous, but might prevent endless/excessive data
-       attacks. */
-    std::string fingerprint(const Store & store) const;
-
-    void sign(const Store & store, const SecretKey & secretKey);
-
-    /* Return true iff the path is verifiably content-addressed. */
-    bool isContentAddressed(const Store & store) const;
-
-    static const size_t maxSigs = std::numeric_limits<size_t>::max();
-
-    /* Return the number of signatures on this .narinfo that were
-       produced by one of the specified keys, or maxSigs if the path
-       is content-addressed. */
-    size_t checkSignatures(const Store & store, const PublicKeys & publicKeys) const;
-
-    /* Verify a single signature. */
-    bool checkSignature(const Store & store, const PublicKeys & publicKeys, const std::string & sig) const;
-
-    Strings shortRefs() const;
-
-    ValidPathInfo(const ValidPathInfo & other) = default;
-
-    ValidPathInfo(StorePath && path) : path(std::move(path)) { };
-    ValidPathInfo(const StorePath & path) : path(path) { };
-
-    virtual ~ValidPathInfo() { }
-};
-
-typedef list<ValidPathInfo> ValidPathInfos;
-
-
 enum BuildMode { bmNormal, bmRepair, bmCheck };
 
 
@@ -344,7 +256,11 @@ public:
         bool hasSelfReference = false) const;
 
     StorePath makeTextPath(std::string_view name, const Hash & hash,
-        const StorePathSet & references) const;
+        const StorePathSet & references = {}) const;
+
+    StorePath makeFixedOutputPathFromCA(std::string_view name, ContentAddress ca,
+        const StorePathSet & references = {},
+        bool hasSelfReference = false) const;
 
     /* This is the preparatory part of addToStore(); it computes the
        store path to which srcPath is to be copied.  Returns the store
@@ -436,9 +352,10 @@ public:
     virtual StorePathSet querySubstitutablePaths(const StorePathSet & paths) { return {}; };
 
     /* Query substitute info (i.e. references, derivers and download
-       sizes) of a set of paths.  If a path does not have substitute
+       sizes) of a map of paths to their optional ca values. If a path
-       info, it's omitted from the resulting ‘infos’ map. */
+       does not have substitute info, it's omitted from the resulting
-    virtual void querySubstitutablePathInfos(const StorePathSet & paths,
+       ‘infos’ map. */
+    virtual void querySubstitutablePathInfos(const StorePathCAMap & paths,
         SubstitutablePathInfos & infos) { return; };
 
     /* Import a path into the store. */
@@ -451,7 +368,7 @@ public:
        libutil/archive.hh). */
     virtual StorePath addToStore(const string & name, const Path & srcPath,
         FileIngestionMethod method = FileIngestionMethod::Recursive, HashType hashAlgo = htSHA256,
-        PathFilter & filter = defaultPathFilter, RepairFlag repair = NoRepair) = 0;
+        PathFilter & filter = defaultPathFilter, RepairFlag repair = NoRepair);
 
     /* Copy the contents of a path to the store and register the
        validity the resulting path, using a constant amount of
@@ -460,6 +377,10 @@ public:
         FileIngestionMethod method = FileIngestionMethod::Recursive, HashType hashAlgo = htSHA256,
         std::optional<Hash> expectedCAHash = {});
 
+    /* Like addToStore(), but the contents of the path are contained
+       in `dump', which is either a NAR serialisation (if recursive ==
+       true) or simply the contents of a regular file (if recursive ==
+       false). */
     // FIXME: remove?
     virtual StorePath addToStoreFromDump(Source & dump, const string & name,
         FileIngestionMethod method = FileIngestionMethod::Recursive, HashType hashAlgo = htSHA256, RepairFlag repair = NoRepair)
@@ -610,7 +531,7 @@ public:
        that will be substituted. */
     virtual void queryMissing(const std::vector<StorePathWithOutputs> & targets,
         StorePathSet & willBuild, StorePathSet & willSubstitute, StorePathSet & unknown,
-        unsigned long long & downloadSize, unsigned long long & narSize);
+        uint64_t & downloadSize, uint64_t & narSize);
 
     /* Sort a set of paths topologically under the references
        relation.  If p refers to q, then p precedes q in this list. */
@@ -740,11 +661,13 @@ void copyStorePath(ref<Store> srcStore, ref<Store> dstStore,
 
 
 /* Copy store paths from one store to another. The paths may be copied
-   in parallel. They are copied in a topologically sorted order
+   in parallel. They are copied in a topologically sorted order (i.e.
-   (i.e. if A is a reference of B, then A is copied before B), but
+   if A is a reference of B, then A is copied before B), but the set
-   the set of store paths is not automatically closed; use
+   of store paths is not automatically closed; use copyClosure() for
-   copyClosure() for that. */
+   that. Returns a map of what each path was copied to the dstStore
-void copyPaths(ref<Store> srcStore, ref<Store> dstStore, const StorePathSet & storePaths,
+   as. */
+std::map<StorePath, StorePath> copyPaths(ref<Store> srcStore, ref<Store> dstStore,
+    const StorePathSet & storePaths,
     RepairFlag repair = NoRepair,
     CheckSigsFlag checkSigs = CheckSigs,
     SubstituteFlag substitute = NoSubstitute);
@@ -843,4 +766,6 @@ std::optional<ValidPathInfo> decodeValidPathInfo(
 /* Split URI into protocol+hierarchy part and its parameter set. */
 std::pair<std::string, Store::Params> splitUriAndParams(const std::string & uri);
 
+std::optional<ContentAddress> getDerivationCA(const BasicDerivation & drv);
+
 }

src/libstore/worker-protocol.hh

@@ -6,7 +6,7 @@ namespace nix {
 #define WORKER_MAGIC_1 0x6e697863
 #define WORKER_MAGIC_2 0x6478696f
 
-#define PROTOCOL_VERSION 0x116
+#define PROTOCOL_VERSION 0x117
 #define GET_PROTOCOL_MAJOR(x) ((x) & 0xff00)
 #define GET_PROTOCOL_MINOR(x) ((x) & 0x00ff)
 
@@ -70,6 +70,10 @@ template<class T> T readStorePaths(const Store & store, Source & from);
 
 void writeStorePaths(const Store & store, Sink & out, const StorePathSet & paths);
 
+StorePathCAMap readStorePathCAMap(const Store & store, Source & from);
+
+void writeStorePathCAMap(const Store & store, Sink & out, const StorePathCAMap & paths);
+
 void writeOutputPathMap(const Store & store, Sink & out, const OutputPathMap & paths);
 
 }

src/libutil/archive.cc

@@ -150,17 +150,17 @@ static void skipGeneric(Source & source)
 
 static void parseContents(ParseSink & sink, Source & source, const Path & path)
 {
-    unsigned long long size = readLongLong(source);
+    uint64_t size = readLongLong(source);
 
     sink.preallocateContents(size);
 
-    unsigned long long left = size;
+    uint64_t left = size;
     std::vector<unsigned char> buf(65536);
 
     while (left) {
         checkInterrupt();
         auto n = buf.size();
-        if ((unsigned long long)n > left) n = left;
+        if ((uint64_t)n > left) n = left;
         source(buf.data(), n);
         sink.receiveContents(buf.data(), n);
         left -= n;
@@ -323,7 +323,7 @@ struct RestoreSink : ParseSink
             throw SysError("fchmod");
     }
 
-    void preallocateContents(unsigned long long len)
+    void preallocateContents(uint64_t len)
     {
 #if HAVE_POSIX_FALLOCATE
         if (len) {
@@ -338,7 +338,7 @@ struct RestoreSink : ParseSink
 #endif
     }
 
-    void receiveContents(unsigned char * data, unsigned int len)
+    void receiveContents(unsigned char * data, size_t len)
     {
         writeFull(fd.get(), data, len);
     }

src/libutil/archive.hh

@@ -57,8 +57,8 @@ struct ParseSink
 
     virtual void createRegularFile(const Path & path) { };
     virtual void isExecutable() { };
-    virtual void preallocateContents(unsigned long long size) { };
+    virtual void preallocateContents(uint64_t size) { };
-    virtual void receiveContents(unsigned char * data, unsigned int len) { };
+    virtual void receiveContents(unsigned char * data, size_t len) { };
 
     virtual void createSymlink(const Path & path, const string & target) { };
 };
@@ -77,7 +77,7 @@ struct RetrieveRegularNARSink : ParseSink
         regular = false;
     }
 
-    void receiveContents(unsigned char * data, unsigned int len)
+    void receiveContents(unsigned char * data, size_t len)
     {
         sink(data, len);
     }

src/libutil/hash.cc

@@ -7,6 +7,7 @@
 #include "args.hh"
 #include "hash.hh"
 #include "archive.hh"
+#include "split.hh"
 #include "util.hh"
 
 #include <sys/types.h>
@@ -15,6 +16,7 @@
 
 namespace nix {
 
+
 static size_t regularHashSize(HashType type) {
     switch (type) {
     case htMD5: return md5HashSize;
@@ -25,10 +27,11 @@ static size_t regularHashSize(HashType type) {
     abort();
 }
 
+
 std::set<std::string> hashTypes = { "md5", "sha1", "sha256", "sha512" };
 
 
-void Hash::init()
+Hash::Hash(HashType type) : type(type)
 {
     hashSize = regularHashSize(type);
     assert(hashSize <= maxHashSize);
@@ -133,57 +136,89 @@ std::string Hash::to_string(Base base, bool includeType) const
     return s;
 }
 
-Hash::Hash(std::string_view s, HashType type) : Hash(s, std::optional { type }) { }
+Hash Hash::parseSRI(std::string_view original) {
-Hash::Hash(std::string_view s) : Hash(s, std::optional<HashType>{}) { }
-
-Hash::Hash(std::string_view original, std::optional<HashType> optType)
-{
     auto rest = original;
 
-    size_t pos = 0;
+    // Parse the has type before the separater, if there was one.
+    auto hashRaw = splitPrefixTo(rest, '-');
+    if (!hashRaw)
+        throw BadHash("hash '%s' is not SRI", original);
+    HashType parsedType = parseHashType(*hashRaw);
+
+    return Hash(rest, parsedType, true);
+}
+
+// Mutates the string to eliminate the prefixes when found
+static std::pair<std::optional<HashType>, bool> getParsedTypeAndSRI(std::string_view & rest) {
     bool isSRI = false;
 
     // Parse the has type before the separater, if there was one.
     std::optional<HashType> optParsedType;
     {
-        auto sep = rest.find(':');
+        auto hashRaw = splitPrefixTo(rest, ':');
-        if (sep == std::string_view::npos) {
+
-            sep = rest.find('-');
+        if (!hashRaw) {
-            if (sep != std::string_view::npos)
+            hashRaw = splitPrefixTo(rest, '-');
+            if (hashRaw)
                 isSRI = true;
         }
-        if (sep != std::string_view::npos) {
+        if (hashRaw)
-            auto hashRaw = rest.substr(0, sep);
+            optParsedType = parseHashType(*hashRaw);
-            optParsedType = parseHashType(hashRaw);
-            rest = rest.substr(sep + 1);
-        }
     }
 
+    return {optParsedType, isSRI};
+}
+
+Hash Hash::parseAnyPrefixed(std::string_view original)
+{
+    auto rest = original;
+    auto [optParsedType, isSRI] = getParsedTypeAndSRI(rest);
+
     // Either the string or user must provide the type, if they both do they
     // must agree.
-    if (!optParsedType && !optType) {
+    if (!optParsedType)
+        throw BadHash("hash '%s' does not include a type", rest);
+
+    return Hash(rest, *optParsedType, isSRI);
+}
+
+Hash Hash::parseAny(std::string_view original, std::optional<HashType> optType)
+{
+    auto rest = original;
+    auto [optParsedType, isSRI] = getParsedTypeAndSRI(rest);
+
+    // Either the string or user must provide the type, if they both do they
+    // must agree.
+    if (!optParsedType && !optType)
         throw BadHash("hash '%s' does not include a type, nor is the type otherwise known from context.", rest);
-    } else {
+    else if (optParsedType && optType && *optParsedType != *optType)
-        this->type = optParsedType ? *optParsedType : *optType;
+        throw BadHash("hash '%s' should have type '%s'", original, printHashType(*optType));
-        if (optParsedType && optType && *optParsedType != *optType)
-            throw BadHash("hash '%s' should have type '%s'", original, printHashType(*optType));
-    }
 
-    init();
+    HashType hashType = optParsedType ? *optParsedType : *optType;
+    return Hash(rest, hashType, isSRI);
+}
 
+Hash Hash::parseNonSRIUnprefixed(std::string_view s, HashType type)
+{
+    return Hash(s, type, false);
+}
+
+Hash::Hash(std::string_view rest, HashType type, bool isSRI)
+    : Hash(type)
+{
     if (!isSRI && rest.size() == base16Len()) {
 
         auto parseHexDigit = [&](char c) {
             if (c >= '0' && c <= '9') return c - '0';
             if (c >= 'A' && c <= 'F') return c - 'A' + 10;
             if (c >= 'a' && c <= 'f') return c - 'a' + 10;
-            throw BadHash("invalid base-16 hash '%s'", original);
+            throw BadHash("invalid base-16 hash '%s'", rest);
         };
 
         for (unsigned int i = 0; i < hashSize; i++) {
             hash[i] =
-                parseHexDigit(rest[pos + i * 2]) << 4
+                parseHexDigit(rest[i * 2]) << 4
-                | parseHexDigit(rest[pos + i * 2 + 1]);
+                | parseHexDigit(rest[i * 2 + 1]);
         }
     }
 
@@ -195,7 +230,7 @@ Hash::Hash(std::string_view original, std::optional<HashType> optType)
             for (digit = 0; digit < base32Chars.size(); ++digit) /* !!! slow */
                 if (base32Chars[digit] == c) break;
             if (digit >= 32)
-                throw BadHash("invalid base-32 hash '%s'", original);
+                throw BadHash("invalid base-32 hash '%s'", rest);
             unsigned int b = n * 5;
             unsigned int i = b / 8;
             unsigned int j = b % 8;
@@ -205,7 +240,7 @@ Hash::Hash(std::string_view original, std::optional<HashType> optType)
                 hash[i + 1] |= digit >> (8 - j);
             } else {
                 if (digit >> (8 - j))
-                    throw BadHash("invalid base-32 hash '%s'", original);
+                    throw BadHash("invalid base-32 hash '%s'", rest);
             }
         }
     }
@@ -213,7 +248,7 @@ Hash::Hash(std::string_view original, std::optional<HashType> optType)
     else if (isSRI || rest.size() == base64Len()) {
         auto d = base64Decode(rest);
         if (d.size() != hashSize)
-            throw BadHash("invalid %s hash '%s'", isSRI ? "SRI" : "base-64", original);
+            throw BadHash("invalid %s hash '%s'", isSRI ? "SRI" : "base-64", rest);
         assert(hashSize);
         memcpy(hash, d.data(), hashSize);
     }
@@ -231,7 +266,7 @@ Hash newHashAllowEmpty(std::string hashStr, std::optional<HashType> ht)
         warn("found empty hash, assuming '%s'", h.to_string(SRI, true));
         return h;
     } else
-        return Hash(hashStr, ht);
+        return Hash::parseAny(hashStr, ht);
 }
 
 

src/libutil/hash.hh

@@ -34,21 +34,31 @@ struct Hash
     HashType type;
 
     /* Create a zero-filled hash object. */
-    Hash(HashType type) : type(type) { init(); };
+    Hash(HashType type);
 
-    /* Initialize the hash from a string representation, in the format
+    /* Parse the hash from a string representation in the format
        "[<type>:]<base16|base32|base64>" or "<type>-<base64>" (a
        Subresource Integrity hash expression). If the 'type' argument
        is not present, then the hash type must be specified in the
        string. */
-    Hash(std::string_view s, std::optional<HashType> type);
+    static Hash parseAny(std::string_view s, std::optional<HashType> type);
-    // type must be provided
-    Hash(std::string_view s, HashType type);
-    // hash type must be part of string
-    Hash(std::string_view s);
 
-    void init();
+    /* Parse a hash from a string representation like the above, except the
+       type prefix is mandatory is there is no separate arguement. */
+    static Hash parseAnyPrefixed(std::string_view s);
 
+    /* Parse a plain hash that musst not have any prefix indicating the type.
+       The type is passed in to disambiguate. */
+    static Hash parseNonSRIUnprefixed(std::string_view s, HashType type);
+
+    static Hash parseSRI(std::string_view original);
+
+private:
+    /* The type must be provided, the string view must not include <type>
+       prefix. `isSRI` helps disambigate the various base-* encodings. */
+    Hash(std::string_view s, HashType type, bool isSRI);
+
+public:
     /* Check whether a hash is set. */
     operator bool () const { return (bool) type; }
 
@@ -111,7 +121,7 @@ Hash hashFile(HashType ht, const Path & path);
 
 /* Compute the hash of the given path.  The hash is defined as
    (essentially) hashString(ht, dumpPath(path)). */
-typedef std::pair<Hash, unsigned long long> HashResult;
+typedef std::pair<Hash, uint64_t> HashResult;
 HashResult hashPath(HashType ht, const Path & path,
     PathFilter & filter = defaultPathFilter);
 
@@ -141,7 +151,7 @@ class HashSink : public BufferedSink, public AbstractHashSink
 private:
     HashType ht;
     Ctx * ctx;
-    unsigned long long bytes;
+    uint64_t bytes;
 
 public:
     HashSink(HashType ht);

src/libutil/serialise.hh

@@ -312,14 +312,14 @@ T readNum(Source & source)
     source(buf, sizeof(buf));
 
     uint64_t n =
-        ((unsigned long long) buf[0]) |
+        ((uint64_t) buf[0]) |
-        ((unsigned long long) buf[1] << 8) |
+        ((uint64_t) buf[1] << 8) |
-        ((unsigned long long) buf[2] << 16) |
+        ((uint64_t) buf[2] << 16) |
-        ((unsigned long long) buf[3] << 24) |
+        ((uint64_t) buf[3] << 24) |
-        ((unsigned long long) buf[4] << 32) |
+        ((uint64_t) buf[4] << 32) |
-        ((unsigned long long) buf[5] << 40) |
+        ((uint64_t) buf[5] << 40) |
-        ((unsigned long long) buf[6] << 48) |
+        ((uint64_t) buf[6] << 48) |
-        ((unsigned long long) buf[7] << 56);
+        ((uint64_t) buf[7] << 56);
 
     if (n > std::numeric_limits<T>::max())
         throw SerialisationError("serialised integer %d is too large for type '%s'", n, typeid(T).name());

src/libutil/split.hh

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <optional>
+#include <string_view>
+
+#include "util.hh"
+
+namespace nix {
+
+// If `separator` is found, we return the portion of the string before the
+// separator, and modify the string argument to contain only the part after the
+// separator. Otherwise, wer return `std::nullopt`, and we leave the argument
+// string alone.
+static inline std::optional<std::string_view> splitPrefixTo(std::string_view & string, char separator) {
+    auto sepInstance = string.find(separator);
+
+    if (sepInstance != std::string_view::npos) {
+        auto prefix = string.substr(0, sepInstance);
+        string.remove_prefix(sepInstance+1);
+        return prefix;
+    }
+
+    return std::nullopt;
+}
+
+static inline bool splitPrefix(std::string_view & string, std::string_view prefix) {
+    bool res = hasPrefix(string, prefix);
+    if (res)
+        string.remove_prefix(prefix.length());
+    return res;
+}
+
+}

src/libutil/topo-sort.hh

@@ -0,0 +1,40 @@
+#include "error.hh"
+
+namespace nix {
+
+template<typename T>
+std::vector<T> topoSort(std::set<T> items,
+        std::function<std::set<T>(const T &)> getChildren,
+        std::function<Error(const T &, const T &)> makeCycleError)
+{
+    std::vector<T> sorted;
+    std::set<T> visited, parents;
+
+    std::function<void(const T & path, const T * parent)> dfsVisit;
+
+    dfsVisit = [&](const T & path, const T * parent) {
+        if (parents.count(path)) throw makeCycleError(path, *parent);
+
+        if (!visited.insert(path).second) return;
+        parents.insert(path);
+
+        std::set<T> references = getChildren(path);
+
+        for (auto & i : references)
+            /* Don't traverse into items that don't exist in our starting set. */
+            if (i != path && items.count(i))
+                dfsVisit(i, &path);
+
+        sorted.push_back(path);
+        parents.erase(path);
+    };
+
+    for (auto & i : items)
+        dfsVisit(i, nullptr);
+
+    std::reverse(sorted.begin(), sorted.end());
+
+    return sorted;
+}
+
+}

src/libutil/util.cc

@@ -374,7 +374,7 @@ void writeLine(int fd, string s)
 }
 
 
-static void _deletePath(int parentfd, const Path & path, unsigned long long & bytesFreed)
+static void _deletePath(int parentfd, const Path & path, uint64_t & bytesFreed)
 {
     checkInterrupt();
 
@@ -414,7 +414,7 @@ static void _deletePath(int parentfd, const Path & path, unsigned long long & by
     }
 }
 
-static void _deletePath(const Path & path, unsigned long long & bytesFreed)
+static void _deletePath(const Path & path, uint64_t & bytesFreed)
 {
     Path dir = dirOf(path);
     if (dir == "")
@@ -435,12 +435,12 @@ static void _deletePath(const Path & path, unsigned long long & bytesFreed)
 
 void deletePath(const Path & path)
 {
-    unsigned long long dummy;
+    uint64_t dummy;
     deletePath(path, dummy);
 }
 
 
-void deletePath(const Path & path, unsigned long long & bytesFreed)
+void deletePath(const Path & path, uint64_t & bytesFreed)
 {
     //Activity act(*logger, lvlDebug, format("recursively deleting path '%1%'") % path);
     bytesFreed = 0;
@@ -494,6 +494,7 @@ std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix)
 {
     Path tmpl(getEnv("TMPDIR").value_or("/tmp") + "/" + prefix + ".XXXXXX");
     // Strictly speaking, this is UB, but who cares...
+    // FIXME: use O_TMPFILE.
     AutoCloseFD fd(mkstemp((char *) tmpl.c_str()));
     if (!fd)
         throw SysError("creating temporary file '%s'", tmpl);
@@ -1449,7 +1450,7 @@ string base64Decode(std::string_view s)
 
         char digit = decode[(unsigned char) c];
         if (digit == -1)
-            throw Error("invalid character in Base64 string");
+            throw Error("invalid character in Base64 string: '%c'", c);
 
         bits += 6;
         d = d << 6 | digit;

src/libutil/util.hh

@@ -125,7 +125,7 @@ void writeLine(int fd, string s);
    second variant returns the number of bytes and blocks freed. */
 void deletePath(const Path & path);
 
-void deletePath(const Path & path, unsigned long long & bytesFreed);
+void deletePath(const Path & path, uint64_t & bytesFreed);
 
 std::string getUserName();
 

src/nix-build/nix-build.cc

@@ -174,7 +174,7 @@ static void _main(int argc, char * * argv)
         else if (*arg == "--run-env") // obsolete
             runEnv = true;
 
-        else if (*arg == "--command" || *arg == "--run") {
+        else if (runEnv && (*arg == "--command" || *arg == "--run")) {
             if (*arg == "--run")
                 interactive = false;
             envCommand = getArg(*arg, arg, end) + "\nexit";
@@ -192,7 +192,7 @@ static void _main(int argc, char * * argv)
         else if (*arg == "--pure") pure = true;
         else if (*arg == "--impure") pure = false;
 
-        else if (*arg == "--packages" || *arg == "-p")
+        else if (runEnv && (*arg == "--packages" || *arg == "-p"))
             packages = true;
 
         else if (inShebang && *arg == "-i") {
@@ -325,7 +325,7 @@ static void _main(int argc, char * * argv)
     auto buildPaths = [&](const std::vector<StorePathWithOutputs> & paths) {
         /* Note: we do this even when !printMissing to efficiently
            fetch binary cache data. */
-        unsigned long long downloadSize, narSize;
+        uint64_t downloadSize, narSize;
         StorePathSet willBuild, willSubstitute, unknown;
         store->queryMissing(paths,
             willBuild, willSubstitute, unknown, downloadSize, narSize);

src/nix-collect-garbage/nix-collect-garbage.cc

@@ -67,10 +67,8 @@ static int _main(int argc, char * * argv)
                 deleteOlderThan = getArg(*arg, arg, end);
             }
             else if (*arg == "--dry-run") dryRun = true;
-            else if (*arg == "--max-freed") {
+            else if (*arg == "--max-freed")
-                long long maxFreed = getIntArg<long long>(*arg, arg, end, true);
+                options.maxFreed = std::max(getIntArg<int64_t>(*arg, arg, end, true), (int64_t) 0);
-                options.maxFreed = maxFreed >= 0 ? maxFreed : 0;
-            }
             else
                 return false;
             return true;

src/nix-prefetch-url/nix-prefetch-url.cc

@@ -157,7 +157,7 @@ static int _main(int argc, char * * argv)
         Hash hash(ht);
         std::optional<StorePath> storePath;
         if (args.size() == 2) {
-            expectedHash = Hash(args[1], ht);
+            expectedHash = Hash::parseAny(args[1], ht);
             const auto recursive = unpack ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
             storePath = store->makeFixedOutputPath(recursive, *expectedHash, name);
             if (store->isValidPath(*storePath))

src/nix-store/nix-store.cc

@@ -130,7 +130,7 @@ static void opRealise(Strings opFlags, Strings opArgs)
     for (auto & i : opArgs)
         paths.push_back(store->followLinksToStorePathWithOutputs(i));
 
-    unsigned long long downloadSize, narSize;
+    uint64_t downloadSize, narSize;
     StorePathSet willBuild, willSubstitute, unknown;
     store->queryMissing(paths, willBuild, willSubstitute, unknown, downloadSize, narSize);
 
@@ -208,7 +208,7 @@ static void opPrintFixedPath(Strings opFlags, Strings opArgs)
     string hash = *i++;
     string name = *i++;
 
-    cout << fmt("%s\n", store->printStorePath(store->makeFixedOutputPath(recursive, Hash(hash, hashAlgo), name)));
+    cout << fmt("%s\n", store->printStorePath(store->makeFixedOutputPath(recursive, Hash::parseAny(hash, hashAlgo), name)));
 }
 
 
@@ -572,10 +572,8 @@ static void opGC(Strings opFlags, Strings opArgs)
         if (*i == "--print-roots") printRoots = true;
         else if (*i == "--print-live") options.action = GCOptions::gcReturnLive;
         else if (*i == "--print-dead") options.action = GCOptions::gcReturnDead;
-        else if (*i == "--max-freed") {
+        else if (*i == "--max-freed")
-            long long maxFreed = getIntArg<long long>(*i, i, opFlags.end(), true);
+            options.maxFreed = std::max(getIntArg<int64_t>(*i, i, opFlags.end(), true), (int64_t) 0);
-            options.maxFreed = maxFreed >= 0 ? maxFreed : 0;
-        }
         else throw UsageError("bad sub-operation '%1%' in GC", *i);
 
     if (!opArgs.empty()) throw UsageError("no arguments expected");
@@ -831,7 +829,7 @@ static void opServe(Strings opFlags, Strings opArgs)
                     for (auto & path : paths)
                         if (!path.isDerivation())
                             paths2.push_back({path});
-                    unsigned long long downloadSize, narSize;
+                    uint64_t downloadSize, narSize;
                     StorePathSet willBuild, willSubstitute, unknown;
                     store->queryMissing(paths2,
                         willBuild, willSubstitute, unknown, downloadSize, narSize);
@@ -950,7 +948,7 @@ static void opServe(Strings opFlags, Strings opArgs)
                 auto deriver = readString(in);
                 if (deriver != "")
                     info.deriver = store->parseStorePath(deriver);
-                info.narHash = Hash(readString(in), htSHA256);
+                info.narHash = Hash::parseAny(readString(in), htSHA256);
                 info.references = readStorePaths<StorePathSet>(*store, in);
                 in >> info.registrationTime >> info.narSize >> info.ultimate;
                 info.sigs = readStrings<StringSet>(in);

src/nix/add-to-store.cc

@@ -9,6 +9,7 @@ struct CmdAddToStore : MixDryRun, StoreCommand
 {
     Path path;
     std::optional<std::string> namePart;
+    FileIngestionMethod ingestionMethod = FileIngestionMethod::Recursive;
 
     CmdAddToStore()
     {
@@ -21,6 +22,13 @@ struct CmdAddToStore : MixDryRun, StoreCommand
             .labels = {"name"},
             .handler = {&namePart},
         });
+
+        addFlag({
+            .longName = "flat",
+            .shortName = 0,
+            .description = "add flat file to the Nix store",
+            .handler = {&ingestionMethod, FileIngestionMethod::Flat},
+        });
     }
 
     std::string description() override
@@ -45,12 +53,19 @@ struct CmdAddToStore : MixDryRun, StoreCommand
 
         auto narHash = hashString(htSHA256, *sink.s);
 
-        ValidPathInfo info(store->makeFixedOutputPath(FileIngestionMethod::Recursive, narHash, *namePart));
+        Hash hash = narHash;
+        if (ingestionMethod == FileIngestionMethod::Flat) {
+            HashSink hsink(htSHA256);
+            readFile(path, hsink);
+            hash = hsink.finish().first;
+        }
+
+        ValidPathInfo info(store->makeFixedOutputPath(ingestionMethod, hash, *namePart));
         info.narHash = narHash;
         info.narSize = sink.s->size();
         info.ca = std::optional { FixedOutputHash {
-            .method = FileIngestionMethod::Recursive,
+            .method = ingestionMethod,
-            .hash = *info.narHash,
+            .hash = hash,
         } };
 
         if (!dryRun) {

src/nix/build.cc

@@ -9,6 +9,7 @@ using namespace nix;
 struct CmdBuild : InstallablesCommand, MixDryRun, MixProfile
 {
     Path outLink = "result";
+    BuildMode buildMode = bmNormal;
 
     CmdBuild()
     {
@@ -26,6 +27,12 @@ struct CmdBuild : InstallablesCommand, MixDryRun, MixProfile
             .description = "do not create a symlink to the build result",
             .handler = {&outLink, Path("")},
         });
+
+        addFlag({
+            .longName = "rebuild",
+            .description = "rebuild an already built package and compare the result to the existing store paths",
+            .handler = {&buildMode, bmCheck},
+        });
     }
 
     std::string description() override
@@ -53,7 +60,7 @@ struct CmdBuild : InstallablesCommand, MixDryRun, MixProfile
 
     void run(ref<Store> store) override
     {
-        auto buildables = build(store, dryRun ? Realise::Nothing : Realise::Outputs, installables);
+        auto buildables = build(store, dryRun ? Realise::Nothing : Realise::Outputs, installables, buildMode);
 
         if (dryRun) return;
 

src/nix/bundle.cc

@@ -0,0 +1,129 @@
+#include "command.hh"
+#include "common-args.hh"
+#include "shared.hh"
+#include "store-api.hh"
+#include "fs-accessor.hh"
+
+using namespace nix;
+
+struct CmdBundle : InstallableCommand
+{
+    std::string bundler = "github:matthewbauer/nix-bundle";
+    std::optional<Path> outLink;
+
+    CmdBundle()
+    {
+        addFlag({
+            .longName = "bundler",
+            .description = "use custom bundler",
+            .labels = {"flake-url"},
+            .handler = {&bundler},
+            .completer = {[&](size_t, std::string_view prefix) {
+                completeFlakeRef(getStore(), prefix);
+            }}
+        });
+
+        addFlag({
+            .longName = "out-link",
+            .shortName = 'o',
+            .description = "path of the symlink to the build result",
+            .labels = {"path"},
+            .handler = {&outLink},
+            .completer = completePath
+        });
+    }
+
+    std::string description() override
+    {
+        return "bundle an application so that it works outside of the Nix store";
+    }
+
+    Examples examples() override
+    {
+        return {
+            Example{
+                "To bundle Hello:",
+                "nix bundle hello"
+            },
+        };
+    }
+
+    Category category() override { return catSecondary; }
+
+    Strings getDefaultFlakeAttrPaths() override
+    {
+        Strings res{"defaultApp." + settings.thisSystem.get()};
+        for (auto & s : SourceExprCommand::getDefaultFlakeAttrPaths())
+            res.push_back(s);
+        return res;
+    }
+
+    Strings getDefaultFlakeAttrPathPrefixes() override
+    {
+        Strings res{"apps." + settings.thisSystem.get() + ".", "packages"};
+        for (auto & s : SourceExprCommand::getDefaultFlakeAttrPathPrefixes())
+            res.push_back(s);
+        return res;
+    }
+
+    void run(ref<Store> store) override
+    {
+        auto evalState = getEvalState();
+
+        auto app = installable->toApp(*evalState);
+        store->buildPaths(app.context);
+
+        auto [bundlerFlakeRef, bundlerName] = parseFlakeRefWithFragment(bundler, absPath("."));
+        const flake::LockFlags lockFlags{ .writeLockFile = false };
+        auto bundler = InstallableFlake(
+            evalState, std::move(bundlerFlakeRef),
+            Strings{bundlerName == "" ? "defaultBundler" : bundlerName},
+            Strings({"bundlers."}), lockFlags);
+
+        Value * arg = evalState->allocValue();
+        evalState->mkAttrs(*arg, 2);
+
+        PathSet context;
+        for (auto & i : app.context)
+            context.insert("=" + store->printStorePath(i.path));
+        mkString(*evalState->allocAttr(*arg, evalState->symbols.create("program")), app.program, context);
+
+        mkString(*evalState->allocAttr(*arg, evalState->symbols.create("system")), settings.thisSystem.get());
+
+        arg->attrs->sort();
+ 
+        auto vRes = evalState->allocValue();
+        evalState->callFunction(*bundler.toValue(*evalState).first, *arg, *vRes, noPos);
+
+        if (!evalState->isDerivation(*vRes))
+            throw Error("the bundler '%s' does not produce a derivation", bundler.what());
+
+        auto attr1 = vRes->attrs->find(evalState->sDrvPath);
+        if (!attr1)
+            throw Error("the bundler '%s' does not produce a derivation", bundler.what());
+
+        PathSet context2;
+        StorePath drvPath = store->parseStorePath(evalState->coerceToPath(*attr1->pos, *attr1->value, context2));
+
+        auto attr2 = vRes->attrs->find(evalState->sOutPath);
+        if (!attr2)
+            throw Error("the bundler '%s' does not produce a derivation", bundler.what());
+
+        StorePath outPath = store->parseStorePath(evalState->coerceToPath(*attr2->pos, *attr2->value, context2));
+
+        store->buildPaths({{drvPath}});
+
+        auto outPathS = store->printStorePath(outPath);
+
+        auto info = store->queryPathInfo(outPath);
+        if (!info->references.empty())
+            throw Error("'%s' has references; a bundler must not leave any references", outPathS);
+
+        if (!outLink)
+            outLink = baseNameOf(app.program);
+
+        store.dynamic_pointer_cast<LocalFSStore>()->addPermRoot(outPath, absPath(*outLink), true);
+    }
+};
+
+static auto r2 = registerCommand<CmdBundle>("bundle");

src/nix/command.hh

@@ -5,6 +5,7 @@
 #include "common-eval-args.hh"
 #include "path.hh"
 #include "flake/lockfile.hh"
+#include "store-api.hh"
 
 #include <optional>
 
@@ -185,7 +186,7 @@ static RegisterCommand registerCommand(const std::string & name)
 }
 
 Buildables build(ref<Store> store, Realise mode,
-    std::vector<std::shared_ptr<Installable>> installables);
+    std::vector<std::shared_ptr<Installable>> installables, BuildMode bMode = bmNormal);
 
 std::set<StorePath> toStorePaths(ref<Store> store,
     Realise mode, OperateOn operateOn,

src/nix/develop.cc

@@ -68,22 +68,22 @@ BuildEnvironment readEnvironment(const Path & path)
 
         std::smatch match;
 
-        if (std::regex_search(pos, file.cend(), match, declareRegex)) {
+        if (std::regex_search(pos, file.cend(), match, declareRegex, std::regex_constants::match_continuous)) {
             pos = match[0].second;
             exported.insert(match[1]);
         }
 
-        else if (std::regex_search(pos, file.cend(), match, varRegex)) {
+        else if (std::regex_search(pos, file.cend(), match, varRegex, std::regex_constants::match_continuous)) {
             pos = match[0].second;
             res.env.insert({match[1], Var { .exported = exported.count(match[1]) > 0, .value = match[2] }});
         }
 
-        else if (std::regex_search(pos, file.cend(), match, assocArrayRegex)) {
+        else if (std::regex_search(pos, file.cend(), match, assocArrayRegex, std::regex_constants::match_continuous)) {
             pos = match[0].second;
             res.env.insert({match[1], Var { .associative = true, .value = match[2] }});
         }
 
-        else if (std::regex_search(pos, file.cend(), match, functionRegex)) {
+        else if (std::regex_search(pos, file.cend(), match, functionRegex, std::regex_constants::match_continuous)) {
             res.bashFunctions = std::string(pos, file.cend());
             break;
         }

src/nix/flake.cc

@@ -368,6 +368,21 @@ struct CmdFlakeCheck : FlakeCommand
             }
         };
 
+        auto checkBundler = [&](const std::string & attrPath, Value & v, const Pos & pos) {
+            try {
+                state->forceValue(v, pos);
+                if (v.type != tLambda)
+                    throw Error("bundler must be a function");
+                if (!v.lambda.fun->formals ||
+                    v.lambda.fun->formals->argNames.find(state->symbols.create("program")) == v.lambda.fun->formals->argNames.end() ||
+                    v.lambda.fun->formals->argNames.find(state->symbols.create("system")) == v.lambda.fun->formals->argNames.end())
+                    throw Error("bundler must take formal arguments 'program' and 'system'");
+            } catch (Error & e) {
+                e.addTrace(pos, hintfmt("while checking the template '%s'", attrPath));
+                throw;
+            }
+        };
+
         {
             Activity act(*logger, lvlInfo, actUnknown, "evaluating flake");
 
@@ -490,6 +505,16 @@ struct CmdFlakeCheck : FlakeCommand
                                     *attr.value, *attr.pos);
                         }
 
+                        else if (name == "defaultBundler")
+                            checkBundler(name, vOutput, pos);
+
+                        else if (name == "bundlers") {
+                            state->forceAttrs(vOutput, pos);
+                            for (auto & attr : *vOutput.attrs)
+                                checkBundler(fmt("%s.%s", name, attr.name),
+                                    *attr.value, *attr.pos);
+                        }
+
                         else
                             warn("unknown flake output '%s'", name);
 

src/nix/hash.cc

@@ -107,7 +107,7 @@ struct CmdToBase : Command
     void run() override
     {
         for (auto s : args)
-            logger->stdout(Hash(s, ht).to_string(base, base == SRI));
+            logger->stdout(Hash::parseAny(s, ht).to_string(base, base == SRI));
     }
 };
 

src/nix/installables.cc

@@ -437,7 +437,7 @@ ref<eval_cache::EvalCache> openEvalCache(
     std::shared_ptr<flake::LockedFlake> lockedFlake,
     bool useEvalCache)
 {
-	auto fingerprint = lockedFlake->getFingerprint();
+    auto fingerprint = lockedFlake->getFingerprint();
     return make_ref<nix::eval_cache::EvalCache>(
         useEvalCache && evalSettings.pureEval
             ? std::optional { std::cref(fingerprint) }
@@ -645,7 +645,7 @@ std::shared_ptr<Installable> SourceExprCommand::parseInstallable(
 }
 
 Buildables build(ref<Store> store, Realise mode,
-    std::vector<std::shared_ptr<Installable>> installables)
+    std::vector<std::shared_ptr<Installable>> installables, BuildMode bMode)
 {
     if (mode == Realise::Nothing)
         settings.readOnlyMode = true;
@@ -671,7 +671,7 @@ Buildables build(ref<Store> store, Realise mode,
     if (mode == Realise::Nothing)
         printMissing(store, pathsToBuild, lvlError);
     else if (mode == Realise::Outputs)
-        store->buildPaths(pathsToBuild);
+        store->buildPaths(pathsToBuild, bMode);
 
     return buildables;
 }

src/nix/path-info.cc

@@ -61,7 +61,7 @@ struct CmdPathInfo : StorePathsCommand, MixJSON
         };
     }
 
-    void printSize(unsigned long long value)
+    void printSize(uint64_t value)
     {
         if (!humanReadable) {
             std::cout << fmt("\t%11d", value);

tests/binary-cache.sh

@@ -218,7 +218,9 @@ outPath=$(nix-build --no-out-link -E '
 
 nix copy --to file://$cacheDir?write-nar-listing=1 $outPath
 
-[[ $(cat $cacheDir/$(basename $outPath).ls) = '{"version":1,"root":{"type":"directory","entries":{"bar":{"type":"regular","size":4,"narOffset":232},"link":{"type":"symlink","target":"xyzzy"}}}}' ]]
+diff -u \
+    <(jq -S < $cacheDir/$(basename $outPath).ls) \
+    <(echo '{"version":1,"root":{"type":"directory","entries":{"bar":{"type":"regular","size":4,"narOffset":232},"link":{"type":"symlink","target":"xyzzy"}}}}' | jq -S)
 
 
 # Test debug info index generation.
@@ -234,4 +236,6 @@ outPath=$(nix-build --no-out-link -E '
 
 nix copy --to "file://$cacheDir?index-debug-info=1&compression=none" $outPath
 
-[[ $(cat $cacheDir/debuginfo/02623eda209c26a59b1a8638ff7752f6b945c26b.debug) = '{"archive":"../nar/100vxs724qr46phz8m24iswmg9p3785hsyagz0kchf6q6gf06sw6.nar","member":"lib/debug/.build-id/02/623eda209c26a59b1a8638ff7752f6b945c26b.debug"}' ]]
+diff -u \
+    <(cat $cacheDir/debuginfo/02623eda209c26a59b1a8638ff7752f6b945c26b.debug | jq -S) \
+    <(echo '{"archive":"../nar/100vxs724qr46phz8m24iswmg9p3785hsyagz0kchf6q6gf06sw6.nar","member":"lib/debug/.build-id/02/623eda209c26a59b1a8638ff7752f6b945c26b.debug"}' | jq -S)

tests/check.sh

@@ -61,30 +61,30 @@ nix-build check.nix -A nondeterministic --no-out-link --repeat 1 2> $TEST_ROOT/l
 [ "$status" = "1" ]
 grep 'differs from previous round' $TEST_ROOT/log
 
-path=$(nix-build check.nix -A fetchurl --no-out-link --hashed-mirrors '')
+path=$(nix-build check.nix -A fetchurl --no-out-link)
 
 chmod +w $path
 echo foo > $path
 chmod -w $path
 
-nix-build check.nix -A fetchurl --no-out-link --check --hashed-mirrors ''
+nix-build check.nix -A fetchurl --no-out-link --check
 # Note: "check" doesn't repair anything, it just compares to the hash stored in the database.
 [[ $(cat $path) = foo ]]
 
-nix-build check.nix -A fetchurl --no-out-link --repair --hashed-mirrors ''
+nix-build check.nix -A fetchurl --no-out-link --repair
 [[ $(cat $path) != foo ]]
 
-nix-build check.nix -A hashmismatch --no-out-link --hashed-mirrors '' || status=$?
+nix-build check.nix -A hashmismatch --no-out-link || status=$?
 [ "$status" = "102" ]
 
 echo -n > ./dummy
-nix-build check.nix -A hashmismatch --no-out-link --hashed-mirrors ''
+nix-build check.nix -A hashmismatch --no-out-link
 echo 'Hello World' > ./dummy
 
-nix-build check.nix -A hashmismatch --no-out-link --check --hashed-mirrors '' || status=$?
+nix-build check.nix -A hashmismatch --no-out-link --check || status=$?
 [ "$status" = "102" ]
 
 # Multiple failures with --keep-going
 nix-build check.nix -A nondeterministic --no-out-link
-nix-build check.nix -A nondeterministic -A hashmismatch --no-out-link --check --keep-going --hashed-mirrors '' || status=$?
+nix-build check.nix -A nondeterministic -A hashmismatch --no-out-link --check --keep-going || status=$?
 [ "$status" = "110" ]

tests/fetchGit.sh

@@ -32,6 +32,8 @@ rev2=$(git -C $repo rev-parse HEAD)
 # Fetch a worktree
 unset _NIX_FORCE_HTTP
 path0=$(nix eval --impure --raw --expr "(builtins.fetchGit file://$TEST_ROOT/worktree).outPath")
+path0_=$(nix eval --impure --raw --expr "(builtins.fetchTree { type = \"git\"; url = file://$TEST_ROOT/worktree; }).outPath")
+[[ $path0 = $path0_ ]]
 export _NIX_FORCE_HTTP=1
 [[ $(tail -n 1 $path0/hello) = "hello" ]]
 
@@ -102,6 +104,12 @@ git -C $repo commit -m 'Bla3' -a
 path4=$(nix eval --impure --refresh --raw --expr "(builtins.fetchGit file://$repo).outPath")
 [[ $path2 = $path4 ]]
 
+nix eval --impure --raw --expr "(builtins.fetchGit { url = $repo; rev = \"$rev2\"; narHash = \"sha256-B5yIPHhEm0eysJKEsO7nqxprh9vcblFxpJG11gXJus1=\"; }).outPath" || status=$?
+[[ "$status" = "102" ]]
+
+path5=$(nix eval --impure --raw --expr "(builtins.fetchGit { url = $repo; rev = \"$rev2\"; narHash = \"sha256-Hr8g6AqANb3xqX28eu1XnjK/3ab8Gv6TJSnkb1LezG9=\"; }).outPath")
+[[ $path = $path5 ]]
+
 # tarball-ttl should be ignored if we specify a rev
 echo delft > $repo/hello
 git -C $repo add hello

tests/fetchurl.sh

@@ -5,7 +5,7 @@ clearStore
 # Test fetching a flat file.
 hash=$(nix-hash --flat --type sha256 ./fetchurl.sh)
 
-outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file://$(pwd)/fetchurl.sh --argstr sha256 $hash --no-out-link --hashed-mirrors '')
+outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file://$(pwd)/fetchurl.sh --argstr sha256 $hash --no-out-link)
 
 cmp $outPath fetchurl.sh
 
@@ -14,7 +14,7 @@ clearStore
 
 hash=$(nix hash-file --type sha512 --base64 ./fetchurl.sh)
 
-outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file://$(pwd)/fetchurl.sh --argstr sha512 $hash --no-out-link --hashed-mirrors '')
+outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file://$(pwd)/fetchurl.sh --argstr sha512 $hash --no-out-link)
 
 cmp $outPath fetchurl.sh
 
@@ -25,26 +25,24 @@ hash=$(nix hash-file ./fetchurl.sh)
 
 [[ $hash =~ ^sha256- ]]
 
-outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file://$(pwd)/fetchurl.sh --argstr hash $hash --no-out-link --hashed-mirrors '')
+outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file://$(pwd)/fetchurl.sh --argstr hash $hash --no-out-link)
 
 cmp $outPath fetchurl.sh
 
-# Test the hashed mirror feature.
+# Test that we can substitute from a different store dir.
 clearStore
 
-hash=$(nix hash-file --type sha512 --base64 ./fetchurl.sh)
+other_store=file://$TEST_ROOT/other_store?store=/fnord/store
-hash32=$(nix hash-file --type sha512 --base16 ./fetchurl.sh)
 
-mirror=$TEST_ROOT/hashed-mirror
+hash=$(nix hash-file --type sha256 --base16 ./fetchurl.sh)
-rm -rf $mirror
-mkdir -p $mirror/sha512
-ln -s $(pwd)/fetchurl.sh $mirror/sha512/$hash32
 
-outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file:///no-such-dir/fetchurl.sh --argstr sha512 $hash --no-out-link --hashed-mirrors "file://$mirror")
+storePath=$(nix --store $other_store add-to-store --flat ./fetchurl.sh)
+
+outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file:///no-such-dir/fetchurl.sh --argstr sha256 $hash --no-out-link --substituters $other_store)
 
 # Test hashed mirrors with an SRI hash.
-nix-build '<nix/fetchurl.nix>' --argstr url file:///no-such-dir/fetchurl.sh --argstr hash $(nix to-sri --type sha512 $hash) \
+nix-build '<nix/fetchurl.nix>' --argstr url file:///no-such-dir/fetchurl.sh --argstr hash $(nix to-sri --type sha256 $hash) \
-          --argstr name bla --no-out-link --hashed-mirrors "file://$mirror"
+          --no-out-link --substituters $other_store
 
 # Test unpacking a NAR.
 rm -rf $TEST_ROOT/archive

tests/filter-source.sh

@@ -10,10 +10,16 @@ touch $TEST_ROOT/filterin/bak
 touch $TEST_ROOT/filterin/bla.c.bak
 ln -s xyzzy $TEST_ROOT/filterin/link
 
-nix-build ./filter-source.nix -o $TEST_ROOT/filterout
+checkFilter() {
+    test ! -e $1/foo/bar
+    test -e $1/xyzzy
+    test -e $1/bak
+    test ! -e $1/bla.c.bak
+    test ! -L $1/link
+}
 
-test ! -e $TEST_ROOT/filterout/foo/bar
+nix-build ./filter-source.nix -o $TEST_ROOT/filterout1
-test -e $TEST_ROOT/filterout/xyzzy
+checkFilter $TEST_ROOT/filterout1
-test -e $TEST_ROOT/filterout/bak
+
-test ! -e $TEST_ROOT/filterout/bla.c.bak
+nix-build ./path.nix -o $TEST_ROOT/filterout2
-test ! -L $TEST_ROOT/filterout/link
+checkFilter $TEST_ROOT/filterout2

tests/nar-access.sh

@@ -26,12 +26,24 @@ nix cat-store $storePath/foo/baz > baz.cat-nar
 diff -u baz.cat-nar $storePath/foo/baz
 
 # Test --json.
-[[ $(nix ls-nar --json $narFile /) = '{"type":"directory","entries":{"foo":{},"foo-x":{},"qux":{},"zyx":{}}}' ]]
+diff -u \
-[[ $(nix ls-nar --json -R $narFile /foo) = '{"type":"directory","entries":{"bar":{"type":"regular","size":0,"narOffset":368},"baz":{"type":"regular","size":0,"narOffset":552},"data":{"type":"regular","size":58,"narOffset":736}}}' ]]
+    <(nix ls-nar --json $narFile / | jq -S) \
-[[ $(nix ls-nar --json -R $narFile /foo/bar) = '{"type":"regular","size":0,"narOffset":368}' ]]
+    <(echo '{"type":"directory","entries":{"foo":{},"foo-x":{},"qux":{},"zyx":{}}}' | jq -S)
-[[ $(nix ls-store --json $storePath) = '{"type":"directory","entries":{"foo":{},"foo-x":{},"qux":{},"zyx":{}}}' ]]
+diff -u \
-[[ $(nix ls-store --json -R $storePath/foo) = '{"type":"directory","entries":{"bar":{"type":"regular","size":0},"baz":{"type":"regular","size":0},"data":{"type":"regular","size":58}}}' ]]
+    <(nix ls-nar --json -R $narFile /foo | jq -S) \
-[[ $(nix ls-store --json -R $storePath/foo/bar) = '{"type":"regular","size":0}' ]]
+    <(echo '{"type":"directory","entries":{"bar":{"type":"regular","size":0,"narOffset":368},"baz":{"type":"regular","size":0,"narOffset":552},"data":{"type":"regular","size":58,"narOffset":736}}}' | jq -S)
+diff -u \
+    <(nix ls-nar --json -R $narFile /foo/bar | jq -S) \
+    <(echo '{"type":"regular","size":0,"narOffset":368}' | jq -S)
+diff -u \
+    <(nix ls-store --json $storePath | jq -S) \
+    <(echo '{"type":"directory","entries":{"foo":{},"foo-x":{},"qux":{},"zyx":{}}}' | jq -S)
+diff -u \
+    <(nix ls-store --json -R $storePath/foo | jq -S) \
+    <(echo '{"type":"directory","entries":{"bar":{"type":"regular","size":0},"baz":{"type":"regular","size":0},"data":{"type":"regular","size":58}}}' | jq -S)
+diff -u \
+    <(nix ls-store --json -R $storePath/foo/bar| jq -S) \
+    <(echo '{"type":"regular","size":0}' | jq -S)
 
 # Test missing files.
 nix ls-store --json -R $storePath/xyzzy 2>&1 | grep 'does not exist in NAR'

tests/path.nix

@@ -0,0 +1,14 @@
+with import ./config.nix;
+
+mkDerivation {
+  name = "filter";
+  builder = builtins.toFile "builder" "ln -s $input $out";
+  input =
+    builtins.path {
+      path = ((builtins.getEnv "TEST_ROOT") + "/filterin");
+      filter = path: type:
+           type != "symlink"
+        && baseNameOf path != "foo"
+        && !((import ./lang/lib.nix).hasSuffix ".bak" (baseNameOf path));
+    };
+}

tests/tarball.sh

@@ -27,10 +27,13 @@ test_tarball() {
 
     nix-build -o $TEST_ROOT/result -E "import (fetchTarball file://$tarball)"
 
-    nix-build --experimental-features flakes -o $TEST_ROOT/result -E "import (fetchTree file://$tarball)"
+    nix-build  -o $TEST_ROOT/result -E "import (fetchTree file://$tarball)"
-    nix-build --experimental-features flakes -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; })"
+    nix-build  -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; })"
-    nix-build --experimental-features flakes -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"$hash\"; })"
+    nix-build  -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"$hash\"; })"
-    nix-build --experimental-features flakes -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"sha256-xdKv2pq/IiwLSnBBJXW8hNowI4MrdZfW+SYqDQs7Tzc=\"; })" 2>&1 | grep 'NAR hash mismatch in input'
+    nix-build  -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"sha256-xdKv2pq/IiwLSnBBJXW8hNowI4MrdZfW+SYqDQs7Tzc=\"; })" 2>&1 | grep 'NAR hash mismatch in input'
+
+    nix-instantiate --strict --eval -E "!((import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"$hash\"; })) ? submodules)" >&2
+    nix-instantiate --strict --eval -E "!((import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"$hash\"; })) ? submodules)" 2>&1 | grep 'true'
 
     nix-instantiate --eval -E '1 + 2' -I fnord=file://no-such-tarball.tar$ext
     nix-instantiate --eval -E 'with <fnord/xyzzy>; 1 + 2' -I fnord=file://no-such-tarball$ext