Merge branch 'structured-attrs-shell' of https://github.com/Ma27/nix

src/libstore/build/derivation-goal.cc

@@ -143,7 +143,6 @@ void DerivationGoal::work()
     (this->*state)();
 }
 
-
 void DerivationGoal::addWantedOutputs(const StringSet & outputs)
 {
     /* If we already want all outputs, there is nothing to do. */
@@ -1074,42 +1073,6 @@ HookReply DerivationGoal::tryBuildHook()
 }
 
 
-StorePathSet DerivationGoal::exportReferences(const StorePathSet & storePaths)
-{
-    StorePathSet paths;
-
-    for (auto & storePath : storePaths) {
-        if (!inputPaths.count(storePath))
-            throw BuildError("cannot export references of path '%s' because it is not in the input closure of the derivation", worker.store.printStorePath(storePath));
-
-        worker.store.computeFSClosure({storePath}, paths);
-    }
-
-    /* If there are derivations in the graph, then include their
-       outputs as well.  This is useful if you want to do things
-       like passing all build-time dependencies of some path to a
-       derivation that builds a NixOS DVD image. */
-    auto paths2 = paths;
-
-    for (auto & j : paths2) {
-        if (j.isDerivation()) {
-            Derivation drv = worker.store.derivationFromPath(j);
-            for (auto & k : drv.outputsAndOptPaths(worker.store)) {
-                if (!k.second.second)
-                    /* FIXME: I am confused why we are calling
-                       `computeFSClosure` on the output path, rather than
-                       derivation itself. That doesn't seem right to me, so I
-                       won't try to implemented this for CA derivations. */
-                    throw UnimplementedError("exportReferences on CA derivations is not yet implemented");
-                worker.store.computeFSClosure(*k.second.second, paths);
-            }
-        }
-    }
-
-    return paths;
-}
-
-
 void DerivationGoal::registerOutputs()
 {
     /* When using a build hook, the build hook can register the output

src/libstore/build/local-derivation-goal.cc

@@ -518,7 +518,7 @@ void LocalDerivationGoal::startBuilder()
             /* Write closure info to <fileName>. */
             writeFile(tmpDir + "/" + fileName,
                 worker.store.makeValidityRegistration(
-                    exportReferences({storePath}), false, false));
+                    worker.store.exportReferences({storePath}, inputPaths), false, false));
         }
     }
 
@@ -1084,113 +1084,28 @@ void LocalDerivationGoal::initEnv()
 }
 
 
-static std::regex shVarName("[A-Za-z_][A-Za-z0-9_]*");
-
-
 void LocalDerivationGoal::writeStructuredAttrs()
 {
-    auto structuredAttrs = parsedDrv->getStructuredAttrs();
+    if (auto structAttrsJson = parsedDrv->prepareStructuredAttrs(worker.store, inputPaths)) {
-    if (!structuredAttrs) return;
+        auto json = structAttrsJson.value();
-
+        nlohmann::json rewritten;
-    auto json = *structuredAttrs;
+        for (auto & [i, v] : json["outputs"].get<nlohmann::json::object_t>()) {
-
-    /* Add an "outputs" object containing the output paths. */
-    nlohmann::json outputs;
-    for (auto & i : drv->outputs) {
             /* The placeholder must have a rewrite, so we use it to cover both the
                cases where we know or don't know the output path ahead of time. */
-        outputs[i.first] = rewriteStrings(hashPlaceholder(i.first), inputRewrites);
+            rewritten[i] = rewriteStrings(v, inputRewrites);
-    }
-    json["outputs"] = outputs;
-
-    /* Handle exportReferencesGraph. */
-    auto e = json.find("exportReferencesGraph");
-    if (e != json.end() && e->is_object()) {
-        for (auto i = e->begin(); i != e->end(); ++i) {
-            std::ostringstream str;
-            {
-                JSONPlaceholder jsonRoot(str, true);
-                StorePathSet storePaths;
-                for (auto & p : *i)
-                    storePaths.insert(worker.store.parseStorePath(p.get<std::string>()));
-                worker.store.pathInfoToJSON(jsonRoot,
-                    exportReferences(storePaths), false, true);
-            }
-            json[i.key()] = nlohmann::json::parse(str.str()); // urgh
-        }
         }
 
-    writeFile(tmpDir + "/.attrs.json", rewriteStrings(json.dump(), inputRewrites));
+        json["outputs"] = rewritten;
-    chownToBuilder(tmpDir + "/.attrs.json");
 
-    /* As a convenience to bash scripts, write a shell file that
+        auto jsonSh = writeStructuredAttrsShell(json);
-       maps all attributes that are representable in bash -
-       namely, strings, integers, nulls, Booleans, and arrays and
-       objects consisting entirely of those values. (So nested
-       arrays or objects are not supported.) */
-
-    auto handleSimpleType = [](const nlohmann::json & value) -> std::optional<std::string> {
-        if (value.is_string())
-            return shellEscape(value);
-
-        if (value.is_number()) {
-            auto f = value.get<float>();
-            if (std::ceil(f) == f)
-                return std::to_string(value.get<int>());
-        }
-
-        if (value.is_null())
-            return std::string("''");
-
-        if (value.is_boolean())
-            return value.get<bool>() ? std::string("1") : std::string("");
-
-        return {};
-    };
-
-    std::string jsonSh;
-
-    for (auto i = json.begin(); i != json.end(); ++i) {
-
-        if (!std::regex_match(i.key(), shVarName)) continue;
-
-        auto & value = i.value();
-
-        auto s = handleSimpleType(value);
-        if (s)
-            jsonSh += fmt("declare %s=%s\n", i.key(), *s);
-
-        else if (value.is_array()) {
-            std::string s2;
-            bool good = true;
-
-            for (auto i = value.begin(); i != value.end(); ++i) {
-                auto s3 = handleSimpleType(i.value());
-                if (!s3) { good = false; break; }
-                s2 += *s3; s2 += ' ';
-            }
-
-            if (good)
-                jsonSh += fmt("declare -a %s=(%s)\n", i.key(), s2);
-        }
-
-        else if (value.is_object()) {
-            std::string s2;
-            bool good = true;
-
-            for (auto i = value.begin(); i != value.end(); ++i) {
-                auto s3 = handleSimpleType(i.value());
-                if (!s3) { good = false; break; }
-                s2 += fmt("[%s]=%s ", shellEscape(i.key()), *s3);
-            }
-
-            if (good)
-                jsonSh += fmt("declare -A %s=(%s)\n", i.key(), s2);
-        }
-    }
 
         writeFile(tmpDir + "/.attrs.sh", rewriteStrings(jsonSh, inputRewrites));
         chownToBuilder(tmpDir + "/.attrs.sh");
+        env["NIX_ATTRS_SH_FILE"] = tmpDir + "/.attrs.sh";
+        writeFile(tmpDir + "/.attrs.json", rewriteStrings(json.dump(), inputRewrites));
+        chownToBuilder(tmpDir + "/.attrs.json");
+        env["NIX_ATTRS_JSON_FILE"] = tmpDir + "/.attrs.json";
+    }
 }
 
 

src/libstore/parsed-derivations.cc

@@ -1,6 +1,8 @@
 #include "parsed-derivations.hh"
 
 #include <nlohmann/json.hpp>
+#include <regex>
+#include "json.hh"
 
 namespace nix {
 
@@ -123,4 +125,109 @@ bool ParsedDerivation::substitutesAllowed() const
     return getBoolAttr("allowSubstitutes", true);
 }
 
+static std::regex shVarName("[A-Za-z_][A-Za-z0-9_]*");
+std::optional<nlohmann::json> ParsedDerivation::prepareStructuredAttrs(Store & store, const StorePathSet & inputPaths)
+{
+    auto structuredAttrs = getStructuredAttrs();
+    if (!structuredAttrs) return std::nullopt;
+
+    auto json = *structuredAttrs;
+
+    /* Add an "outputs" object containing the output paths. */
+    nlohmann::json outputs;
+    for (auto & i : drv.outputs) {
+        outputs[i.first] = hashPlaceholder(i.first);
+    }
+    json["outputs"] = outputs;
+
+    /* Handle exportReferencesGraph. */
+    auto e = json.find("exportReferencesGraph");
+    if (e != json.end() && e->is_object()) {
+        for (auto i = e->begin(); i != e->end(); ++i) {
+            std::ostringstream str;
+            {
+                JSONPlaceholder jsonRoot(str, true);
+                StorePathSet storePaths;
+                for (auto & p : *i)
+                    storePaths.insert(store.parseStorePath(p.get<std::string>()));
+                store.pathInfoToJSON(jsonRoot,
+                    store.exportReferences(storePaths, inputPaths), false, true);
+            }
+            json[i.key()] = nlohmann::json::parse(str.str()); // urgh
+        }
+    }
+
+    return json;
+}
+
+/* As a convenience to bash scripts, write a shell file that
+   maps all attributes that are representable in bash -
+   namely, strings, integers, nulls, Booleans, and arrays and
+   objects consisting entirely of those values. (So nested
+   arrays or objects are not supported.) */
+std::string writeStructuredAttrsShell(nlohmann::json & json)
+{
+
+    auto handleSimpleType = [](const nlohmann::json & value) -> std::optional<std::string> {
+        if (value.is_string())
+            return shellEscape(value);
+
+        if (value.is_number()) {
+            auto f = value.get<float>();
+            if (std::ceil(f) == f)
+                return std::to_string(value.get<int>());
+        }
+
+        if (value.is_null())
+            return std::string("''");
+
+        if (value.is_boolean())
+            return value.get<bool>() ? std::string("1") : std::string("");
+
+        return {};
+    };
+
+    std::string jsonSh;
+
+    for (auto i = json.begin(); i != json.end(); ++i) {
+
+        if (!std::regex_match(i.key(), shVarName)) continue;
+
+        auto & value = i.value();
+
+        auto s = handleSimpleType(value);
+        if (s)
+            jsonSh += fmt("declare %s=%s\n", i.key(), *s);
+
+        else if (value.is_array()) {
+            std::string s2;
+            bool good = true;
+
+            for (auto i = value.begin(); i != value.end(); ++i) {
+                auto s3 = handleSimpleType(i.value());
+                if (!s3) { good = false; break; }
+                s2 += *s3; s2 += ' ';
+            }
+
+            if (good)
+                jsonSh += fmt("declare -a %s=(%s)\n", i.key(), s2);
+        }
+
+        else if (value.is_object()) {
+            std::string s2;
+            bool good = true;
+
+            for (auto i = value.begin(); i != value.end(); ++i) {
+                auto s3 = handleSimpleType(i.value());
+                if (!s3) { good = false; break; }
+                s2 += fmt("[%s]=%s ", shellEscape(i.key()), *s3);
+            }
+
+            if (good)
+                jsonSh += fmt("declare -A %s=(%s)\n", i.key(), s2);
+        }
+    }
+
+    return jsonSh;
+}
 }

src/libstore/parsed-derivations.hh

@@ -36,6 +36,10 @@ public:
     bool willBuildLocally(Store & localStore) const;
 
     bool substitutesAllowed() const;
+
+    std::optional<nlohmann::json> prepareStructuredAttrs(Store & store, const StorePathSet & inputPaths);
 };
 
+std::string writeStructuredAttrsShell(nlohmann::json & json);
+
 }

src/libstore/store-api.cc

@@ -634,6 +634,42 @@ string Store::makeValidityRegistration(const StorePathSet & paths,
 }
 
 
+StorePathSet Store::exportReferences(const StorePathSet & storePaths, const StorePathSet & inputPaths)
+{
+    StorePathSet paths;
+
+    for (auto & storePath : storePaths) {
+        if (!inputPaths.count(storePath))
+            throw BuildError("cannot export references of path '%s' because it is not in the input closure of the derivation", printStorePath(storePath));
+
+        computeFSClosure({storePath}, paths);
+    }
+
+    /* If there are derivations in the graph, then include their
+       outputs as well.  This is useful if you want to do things
+       like passing all build-time dependencies of some path to a
+       derivation that builds a NixOS DVD image. */
+    auto paths2 = paths;
+
+    for (auto & j : paths2) {
+        if (j.isDerivation()) {
+            Derivation drv = derivationFromPath(j);
+            for (auto & k : drv.outputsAndOptPaths(*this)) {
+                if (!k.second.second)
+                    /* FIXME: I am confused why we are calling
+                       `computeFSClosure` on the output path, rather than
+                       derivation itself. That doesn't seem right to me, so I
+                       won't try to implemented this for CA derivations. */
+                    throw UnimplementedError("exportReferences on CA derivations is not yet implemented");
+                computeFSClosure(*k.second.second, paths);
+            }
+        }
+    }
+
+    return paths;
+}
+
+
 void Store::pathInfoToJSON(JSONPlaceholder & jsonOut, const StorePathSet & storePaths,
     bool includeImpureInfo, bool showClosureSize,
     Base hashBase,

src/libstore/store-api.hh

@@ -697,6 +697,11 @@ public:
 
     const Stats & getStats();
 
+    /* Computes the full closure of of a set of store-paths for e.g.
+       derivations that need this information for `exportReferencesGraph`.
+     */
+    StorePathSet exportReferences(const StorePathSet & storePaths, const StorePathSet & inputPaths);
+
     /* Return the build log of the specified store path, if available,
        or null otherwise. */
     virtual std::shared_ptr<std::string> getBuildLog(const StorePath & path)

src/nix-build/nix-build.cc

@@ -1,10 +1,15 @@
 #include <cstring>
 #include <fstream>
 #include <iostream>
+#include <filesystem>
 #include <regex>
 #include <sstream>
 #include <vector>
+#include <map>
 
+#include <nlohmann/json.hpp>
+
+#include "parsed-derivations.hh"
 #include "store-api.hh"
 #include "local-fs-store.hh"
 #include "globals.hh"
@@ -428,12 +433,45 @@ static void main_nix_build(int argc, char * * argv)
             } else
                 env[var.first] = var.second;
 
+        std::string structuredAttrsRC;
+
+        if (env.count("__json")) {
+            StorePathSet inputs;
+            for (auto & [depDrvPath, wantedDepOutputs] : drv.inputDrvs) {
+                auto outputs = store->queryPartialDerivationOutputMap(depDrvPath);
+                for (auto & i : wantedDepOutputs) {
+                    auto o = outputs.at(i);
+                    store->computeFSClosure(*o, inputs);
+                }
+            }
+
+            ParsedDerivation parsedDrv(
+                StorePath(store->parseStorePath(drvInfo.queryDrvPath())),
+                drv
+            );
+
+            if (auto structAttrs = parsedDrv.prepareStructuredAttrs(*store, inputs)) {
+                auto json = structAttrs.value();
+                structuredAttrsRC = writeStructuredAttrsShell(json);
+
+                auto attrsJSON = (Path) tmpDir + "/.attrs.json";
+                writeFile(attrsJSON, json.dump());
+
+                auto attrsSH = (Path) tmpDir + "/.attrs.sh";
+                writeFile(attrsSH, structuredAttrsRC);
+
+                env["NIX_ATTRS_SH_FILE"] = attrsSH;
+                env["NIX_ATTRS_JSON_FILE"] = attrsJSON;
+                keepTmp = true;
+            }
+        }
+
         /* Run a shell using the derivation's environment.  For
            convenience, source $stdenv/setup to setup additional
            environment variables and shell functions.  Also don't
            lose the current $PATH directories. */
         auto rcfile = (Path) tmpDir + "/rc";
-        writeFile(rcfile, fmt(
+        std::string rc = fmt(
                 R"(_nix_shell_clean_tmpdir() { rm -rf %1%; }; )"s +
                 (keepTmp ?
                     "trap _nix_shell_clean_tmpdir EXIT; "
@@ -442,8 +480,9 @@ static void main_nix_build(int argc, char * * argv)
                     "_nix_shell_clean_tmpdir; ") +
                 (pure ? "" : "[ -n \"$PS1\" ] && [ -e ~/.bashrc ] && source ~/.bashrc;") +
                 "%2%"
-                "dontAddDisableDepTrack=1; "
+                "dontAddDisableDepTrack=1;\n"
-                "[ -e $stdenv/setup ] && source $stdenv/setup; "
+                + structuredAttrsRC +
+                "\n[ -e $stdenv/setup ] && source $stdenv/setup; "
                 "%3%"
                 "PATH=%4%:\"$PATH\"; "
                 "SHELL=%5%; "
@@ -461,7 +500,9 @@ static void main_nix_build(int argc, char * * argv)
                 shellEscape(dirOf(*shell)),
                 shellEscape(*shell),
                 (getenv("TZ") ? (string("export TZ=") + shellEscape(getenv("TZ")) + "; ") : ""),
-                envCommand));
+                envCommand);
+        vomit("Sourcing nix-shell with file %s and contents:\n%s", rcfile, rc);
+        writeFile(rcfile, rc);
 
         Strings envStrs;
         for (auto & i : env)

src/nix/develop.cc

@@ -147,6 +147,10 @@ struct BuildEnvironment
             return tokenizeString<Array>(str->value);
         else if (auto arr = std::get_if<Array>(&value)) {
             return *arr;
+        } else if (auto assoc = std::get_if<Associative>(&value)) {
+            Array assocKeys;
+            std::for_each(assoc->begin(), assoc->end(), [&](auto & n) { assocKeys.push_back(n.first); });
+            return assocKeys;
         }
         else
             throw Error("bash variable is not a string or array");

src/nix/get-env.sh

@@ -111,12 +111,20 @@ __escapeString() {
     printf '"%s"' "$__s"
 }
 
-# Dump the bash environment as JSON.
+# In case of `__structuredAttrs = true;` the list of outputs is an associative
-for __output in $outputs; do
+# array with a format like `outname => /nix/store/hash-drvname-outname`, so `__olist`
+# must contain the array's keys (hence `${!...[@]}`) in this case.
+if [ -e .attrs.sh ]; then
+    __olist="${!outputs[@]}"
+else
+    __olist=$outputs
+fi
+
+for __output in $__olist; do
     if [[ -z $__done ]]; then
         __dumpEnv > ${!__output}
         __done=1
     else
-        echo -n >> ${!__output}
+        echo -n >> "${!__output}"
     fi
 done

tests/shell.nix

@@ -20,6 +20,15 @@ let pkgs = rec {
     for pkg in $buildInputs; do
       export PATH=$PATH:$pkg/bin
     done
+
+    # mimic behavior of stdenv for `$out` etc. for structured attrs.
+    if [ -n "''${NIX_ATTRS_SH_FILE}" ]; then
+      for o in "''${!outputs[@]}"; do
+        eval "''${o}=''${outputs[$o]}"
+        export "''${o}"
+      done
+    fi
+
     declare -a arr1=(1 2 "3 4" 5)
     declare -a arr2=(x $'\n' $'x\ny')
     fun() {

tests/structured-attrs-shell.nix

@@ -0,0 +1,21 @@
+with import ./config.nix;
+let
+  dep = mkDerivation {
+    name = "dep";
+    buildCommand = ''
+      mkdir $out; echo bla > $out/bla
+    '';
+  };
+  inherit (import ./shell.nix { inNixShell = true; }) stdenv;
+in
+mkDerivation {
+  name = "structured2";
+  __structuredAttrs = true;
+  inherit stdenv;
+  outputs = [ "out" "dev" ];
+  my.list = [ "a" "b" "c" ];
+  exportReferencesGraph.refs = [ dep ];
+  buildCommand = ''
+    touch ''${outputs[out]}; touch ''${outputs[dev]}
+  '';
+}

tests/structured-attrs.nix

@@ -36,7 +36,7 @@ mkDerivation {
     echo bar > $dest
     echo foo > $dest2
 
-    json=$(cat .attrs.json)
+    json=$(cat $NIX_ATTRS_JSON_FILE)
     [[ $json =~ '"narHash":"sha256:1r7yc43zqnzl5b0als5vnyp649gk17i37s7mj00xr8kc47rjcybk"' ]]
     [[ $json =~ '"narSize":288' ]]
     [[ $json =~ '"closureSize":288' ]]

tests/structured-attrs.sh

@@ -8,3 +8,12 @@ nix-build structured-attrs.nix -A all -o $TEST_ROOT/result
 
 [[ $(cat $TEST_ROOT/result/foo) = bar ]]
 [[ $(cat $TEST_ROOT/result-dev/foo) = foo ]]
+
+export NIX_BUILD_SHELL=$SHELL
+env NIX_PATH=nixpkgs=shell.nix nix-shell structured-attrs-shell.nix \
+    --run 'test -e .attrs.json; test "3" = "$(jq ".my.list|length" < $NIX_ATTRS_JSON_FILE)"'
+
+# `nix develop` is a slightly special way of dealing with environment vars, it parses
+# these from a shell-file exported from a derivation. This is to test especially `outputs`
+# (which is an associative array in thsi case) being fine.
+nix develop -f structured-attrs-shell.nix -c bash -c 'test -n "$out"'