forked from lix-project/lix
489 lines
17 KiB
C++
489 lines
17 KiB
C++
#include "primops.hh"
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#include "eval-inline.hh"
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#include "store-api.hh"
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#include "fetchers.hh"
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#include "filetransfer.hh"
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#include "registry.hh"
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#include "url.hh"
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#include <ctime>
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#include <iomanip>
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#include <regex>
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namespace nix {
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void emitTreeAttrs(
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EvalState & state,
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const fetchers::Tree & tree,
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const fetchers::Input & input,
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Value & v,
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bool emptyRevFallback,
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bool forceDirty)
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{
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assert(input.isLocked());
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auto attrs = state.buildBindings(8);
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auto storePath = state.store->printStorePath(tree.storePath);
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attrs.alloc(state.sOutPath).mkString(storePath, {storePath});
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// FIXME: support arbitrary input attributes.
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auto narHash = input.getNarHash();
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assert(narHash);
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attrs.alloc("narHash").mkString(narHash->to_string(SRI, true));
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if (input.getType() == "git")
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attrs.alloc("submodules").mkBool(
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fetchers::maybeGetBoolAttr(input.attrs, "submodules").value_or(false));
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if (!forceDirty) {
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if (auto rev = input.getRev()) {
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attrs.alloc("rev").mkString(rev->gitRev());
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attrs.alloc("shortRev").mkString(rev->gitShortRev());
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} else if (emptyRevFallback) {
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// Backwards compat for `builtins.fetchGit`: dirty repos return an empty sha1 as rev
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auto emptyHash = Hash(htSHA1);
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attrs.alloc("rev").mkString(emptyHash.gitRev());
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attrs.alloc("shortRev").mkString(emptyHash.gitShortRev());
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}
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if (auto revCount = input.getRevCount())
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attrs.alloc("revCount").mkInt(*revCount);
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else if (emptyRevFallback)
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attrs.alloc("revCount").mkInt(0);
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}
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if (auto lastModified = input.getLastModified()) {
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attrs.alloc("lastModified").mkInt(*lastModified);
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attrs.alloc("lastModifiedDate").mkString(
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fmt("%s", std::put_time(std::gmtime(&*lastModified), "%Y%m%d%H%M%S")));
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}
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v.mkAttrs(attrs);
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}
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std::string fixURI(std::string uri, EvalState & state, const std::string & defaultScheme = "file")
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{
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state.checkURI(uri);
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if (uri.find("://") == std::string::npos) {
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const auto p = ParsedURL {
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.scheme = defaultScheme,
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.authority = "",
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.path = uri
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};
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return p.to_string();
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} else {
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return uri;
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}
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}
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std::string fixURIForGit(std::string uri, EvalState & state)
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{
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/* Detects scp-style uris (e.g. git@github.com:NixOS/nix) and fixes
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* them by removing the `:` and assuming a scheme of `ssh://`
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* */
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static std::regex scp_uri("([^/]*)@(.*):(.*)");
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if (uri[0] != '/' && std::regex_match(uri, scp_uri))
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return fixURI(std::regex_replace(uri, scp_uri, "$1@$2/$3"), state, "ssh");
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else
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return fixURI(uri, state);
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}
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struct FetchTreeParams {
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bool emptyRevFallback = false;
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bool allowNameArgument = false;
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};
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static void fetchTree(
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EvalState & state,
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const PosIdx pos,
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Value * * args,
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Value & v,
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std::optional<std::string> type,
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const FetchTreeParams & params = FetchTreeParams{}
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) {
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fetchers::Input input;
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PathSet context;
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state.forceValue(*args[0], pos);
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if (args[0]->type() == nAttrs) {
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state.forceAttrs(*args[0], pos, "while evaluating the argument passed to builtins.fetchTree");
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fetchers::Attrs attrs;
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if (auto aType = args[0]->attrs->get(state.sType)) {
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if (type)
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state.debugThrowLastTrace(EvalError({
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.msg = hintfmt("unexpected attribute 'type'"),
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.errPos = state.positions[pos]
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}));
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type = state.forceStringNoCtx(*aType->value, aType->pos, "while evaluating the `type` attribute passed to builtins.fetchTree");
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} else if (!type)
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state.debugThrowLastTrace(EvalError({
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.msg = hintfmt("attribute 'type' is missing in call to 'fetchTree'"),
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.errPos = state.positions[pos]
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}));
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attrs.emplace("type", type.value());
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for (auto & attr : *args[0]->attrs) {
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if (attr.name == state.sType) continue;
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state.forceValue(*attr.value, attr.pos);
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if (attr.value->type() == nPath || attr.value->type() == nString) {
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auto s = state.coerceToString(attr.pos, *attr.value, context, "", false, false).toOwned();
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attrs.emplace(state.symbols[attr.name],
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state.symbols[attr.name] == "url"
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? type == "git"
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? fixURIForGit(s, state)
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: fixURI(s, state)
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: s);
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}
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else if (attr.value->type() == nBool)
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attrs.emplace(state.symbols[attr.name], Explicit<bool>{attr.value->boolean});
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else if (attr.value->type() == nInt)
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attrs.emplace(state.symbols[attr.name], uint64_t(attr.value->integer));
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else
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state.debugThrowLastTrace(TypeError("fetchTree argument '%s' is %s while a string, Boolean or integer is expected",
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state.symbols[attr.name], showType(*attr.value)));
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}
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if (!params.allowNameArgument)
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if (auto nameIter = attrs.find("name"); nameIter != attrs.end())
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state.debugThrowLastTrace(EvalError({
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.msg = hintfmt("attribute 'name' isn’t supported in call to 'fetchTree'"),
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.errPos = state.positions[pos]
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}));
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input = fetchers::Input::fromAttrs(std::move(attrs));
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} else {
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auto url = state.coerceToString(pos, *args[0], context,
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"while evaluating the first argument passed to the fetcher",
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false, false).toOwned();
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if (type == "git") {
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fetchers::Attrs attrs;
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attrs.emplace("type", "git");
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attrs.emplace("url", fixURIForGit(url, state));
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input = fetchers::Input::fromAttrs(std::move(attrs));
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} else {
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input = fetchers::Input::fromURL(fixURI(url, state));
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}
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}
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if (!evalSettings.pureEval && !input.isDirect())
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input = lookupInRegistries(state.store, input).first;
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if (evalSettings.pureEval && !input.isLocked())
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state.debugThrowLastTrace(EvalError("in pure evaluation mode, 'fetchTree' requires a locked input, at %s", state.positions[pos]));
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auto [tree, input2] = input.fetch(state.store);
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state.allowPath(tree.storePath);
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emitTreeAttrs(state, tree, input2, v, params.emptyRevFallback, false);
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}
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static void prim_fetchTree(EvalState & state, const PosIdx pos, Value * * args, Value & v)
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{
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settings.requireExperimentalFeature(Xp::Flakes);
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fetchTree(state, pos, args, v, std::nullopt, FetchTreeParams { .allowNameArgument = false });
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}
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// FIXME: document
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static RegisterPrimOp primop_fetchTree("fetchTree", 1, prim_fetchTree);
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static void fetch(EvalState & state, const PosIdx pos, Value * * args, Value & v,
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const std::string & who, bool unpack, std::string name)
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{
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std::optional<std::string> url;
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std::optional<Hash> expectedHash;
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state.forceValue(*args[0], pos);
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if (args[0]->type() == nAttrs) {
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for (auto & attr : *args[0]->attrs) {
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std::string_view n(state.symbols[attr.name]);
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if (n == "url")
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url = state.forceStringNoCtx(*attr.value, attr.pos, "while evaluating the url we should fetch");
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else if (n == "sha256")
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expectedHash = newHashAllowEmpty(state.forceStringNoCtx(*attr.value, attr.pos, "while evaluating the sha256 of the content we should fetch"), htSHA256);
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else if (n == "name")
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name = state.forceStringNoCtx(*attr.value, attr.pos, "while evaluating the name of the content we should fetch");
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else
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state.debugThrowLastTrace(EvalError({
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.msg = hintfmt("unsupported argument '%s' to '%s'", n, who),
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.errPos = state.positions[attr.pos]
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}));
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}
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if (!url)
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state.debugThrowLastTrace(EvalError({
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.msg = hintfmt("'url' argument required"),
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.errPos = state.positions[pos]
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}));
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} else
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url = state.forceStringNoCtx(*args[0], pos, "while evaluating the url we should fetch");
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if (who == "fetchTarball")
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url = evalSettings.resolvePseudoUrl(*url);
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state.checkURI(*url);
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if (name == "")
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name = baseNameOf(*url);
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if (evalSettings.pureEval && !expectedHash)
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state.debugThrowLastTrace(EvalError("in pure evaluation mode, '%s' requires a 'sha256' argument", who));
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// early exit if pinned and already in the store
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if (expectedHash && expectedHash->type == htSHA256) {
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auto expectedPath = state.store->makeFixedOutputPath(
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name,
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FixedOutputInfo {
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{
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.method = unpack ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat,
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.hash = *expectedHash,
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},
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/* .references = */ {}
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});
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if (state.store->isValidPath(expectedPath)) {
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state.allowAndSetStorePathString(expectedPath, v);
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return;
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}
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}
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// TODO: fetching may fail, yet the path may be substitutable.
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// https://github.com/NixOS/nix/issues/4313
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auto storePath =
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unpack
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? fetchers::downloadTarball(state.store, *url, name, (bool) expectedHash).first.storePath
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: fetchers::downloadFile(state.store, *url, name, (bool) expectedHash).storePath;
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if (expectedHash) {
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auto hash = unpack
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? state.store->queryPathInfo(storePath)->narHash
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: hashFile(htSHA256, state.store->toRealPath(storePath));
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if (hash != *expectedHash)
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state.debugThrowLastTrace(EvalError((unsigned int) 102, "hash mismatch in file downloaded from '%s':\n specified: %s\n got: %s",
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*url, expectedHash->to_string(Base32, true), hash.to_string(Base32, true)));
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}
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state.allowAndSetStorePathString(storePath, v);
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}
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static void prim_fetchurl(EvalState & state, const PosIdx pos, Value * * args, Value & v)
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{
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fetch(state, pos, args, v, "fetchurl", false, "");
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}
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static RegisterPrimOp primop_fetchurl({
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.name = "__fetchurl",
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.args = {"url"},
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.doc = R"(
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Download the specified URL and return the path of the downloaded
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file. This function is not available if [restricted evaluation
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mode](../command-ref/conf-file.md) is enabled.
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)",
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.fun = prim_fetchurl,
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});
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static void prim_fetchTarball(EvalState & state, const PosIdx pos, Value * * args, Value & v)
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{
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fetch(state, pos, args, v, "fetchTarball", true, "source");
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}
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static RegisterPrimOp primop_fetchTarball({
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.name = "fetchTarball",
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.args = {"args"},
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.doc = R"(
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Download the specified URL, unpack it and return the path of the
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unpacked tree. The file must be a tape archive (`.tar`) compressed
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with `gzip`, `bzip2` or `xz`. The top-level path component of the
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files in the tarball is removed, so it is best if the tarball
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contains a single directory at top level. The typical use of the
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function is to obtain external Nix expression dependencies, such as
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a particular version of Nixpkgs, e.g.
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```nix
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with import (fetchTarball https://github.com/NixOS/nixpkgs/archive/nixos-14.12.tar.gz) {};
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stdenv.mkDerivation { … }
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```
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The fetched tarball is cached for a certain amount of time (1
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hour by default) in `~/.cache/nix/tarballs/`. You can change the
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cache timeout either on the command line with `--tarball-ttl`
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*number-of-seconds* or in the Nix configuration file by adding
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the line `tarball-ttl = ` *number-of-seconds*.
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Note that when obtaining the hash with `nix-prefetch-url` the
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option `--unpack` is required.
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This function can also verify the contents against a hash. In that
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case, the function takes a set instead of a URL. The set requires
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the attribute `url` and the attribute `sha256`, e.g.
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```nix
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with import (fetchTarball {
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url = "https://github.com/NixOS/nixpkgs/archive/nixos-14.12.tar.gz";
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sha256 = "1jppksrfvbk5ypiqdz4cddxdl8z6zyzdb2srq8fcffr327ld5jj2";
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}) {};
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stdenv.mkDerivation { … }
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```
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This function is not available if [restricted evaluation
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mode](../command-ref/conf-file.md) is enabled.
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)",
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.fun = prim_fetchTarball,
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});
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static void prim_fetchGit(EvalState & state, const PosIdx pos, Value * * args, Value & v)
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{
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fetchTree(state, pos, args, v, "git", FetchTreeParams { .emptyRevFallback = true, .allowNameArgument = true });
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}
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static RegisterPrimOp primop_fetchGit({
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.name = "fetchGit",
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.args = {"args"},
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.doc = R"(
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Fetch a path from git. *args* can be a URL, in which case the HEAD
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of the repo at that URL is fetched. Otherwise, it can be an
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attribute with the following attributes (all except `url` optional):
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- url\
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The URL of the repo.
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- name\
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The name of the directory the repo should be exported to in the
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store. Defaults to the basename of the URL.
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- rev\
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The git revision to fetch. Defaults to the tip of `ref`.
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- ref\
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The git ref to look for the requested revision under. This is
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often a branch or tag name. Defaults to `HEAD`.
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By default, the `ref` value is prefixed with `refs/heads/`. As
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of Nix 2.3.0 Nix will not prefix `refs/heads/` if `ref` starts
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with `refs/`.
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- submodules\
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A Boolean parameter that specifies whether submodules should be
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checked out. Defaults to `false`.
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- shallow\
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A Boolean parameter that specifies whether fetching a shallow clone
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is allowed. Defaults to `false`.
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- allRefs\
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Whether to fetch all refs of the repository. With this argument being
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true, it's possible to load a `rev` from *any* `ref` (by default only
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`rev`s from the specified `ref` are supported).
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Here are some examples of how to use `fetchGit`.
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- To fetch a private repository over SSH:
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```nix
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builtins.fetchGit {
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url = "git@github.com:my-secret/repository.git";
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ref = "master";
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rev = "adab8b916a45068c044658c4158d81878f9ed1c3";
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}
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```
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- To fetch an arbitrary reference:
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```nix
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builtins.fetchGit {
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url = "https://github.com/NixOS/nix.git";
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ref = "refs/heads/0.5-release";
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}
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```
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- If the revision you're looking for is in the default branch of
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the git repository you don't strictly need to specify the branch
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name in the `ref` attribute.
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However, if the revision you're looking for is in a future
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branch for the non-default branch you will need to specify the
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the `ref` attribute as well.
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```nix
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builtins.fetchGit {
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url = "https://github.com/nixos/nix.git";
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rev = "841fcbd04755c7a2865c51c1e2d3b045976b7452";
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ref = "1.11-maintenance";
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}
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```
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> **Note**
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>
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> It is nice to always specify the branch which a revision
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> belongs to. Without the branch being specified, the fetcher
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> might fail if the default branch changes. Additionally, it can
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> be confusing to try a commit from a non-default branch and see
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> the fetch fail. If the branch is specified the fault is much
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> more obvious.
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- If the revision you're looking for is in the default branch of
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the git repository you may omit the `ref` attribute.
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```nix
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builtins.fetchGit {
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url = "https://github.com/nixos/nix.git";
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rev = "841fcbd04755c7a2865c51c1e2d3b045976b7452";
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}
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```
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- To fetch a specific tag:
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```nix
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builtins.fetchGit {
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url = "https://github.com/nixos/nix.git";
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ref = "refs/tags/1.9";
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}
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```
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- To fetch the latest version of a remote branch:
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```nix
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builtins.fetchGit {
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url = "ssh://git@github.com/nixos/nix.git";
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ref = "master";
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}
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```
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> **Note**
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>
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> Nix will refetch the branch in accordance with
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> the option `tarball-ttl`.
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> **Note**
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>
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> This behavior is disabled in *Pure evaluation mode*.
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- To fetch the content of a checked-out work directory:
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```nix
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builtins.fetchGit ./work-dir
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```
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If the URL points to a local directory, and no `ref` or `rev` is
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given, `fetchGit` will use the current content of the checked-out
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files, even if they are not committed or added to Git's index. It will
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only consider files added to the Git repository, as listed by `git ls-files`.
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)",
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.fun = prim_fetchGit,
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});
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}
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