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Further consolidate environment variable processing outside DerivationBuilder

Browse source 
Now, `DerivationBuilder` only concerns itself with `finalEnv` and
`extraFiles`, in straightforward unconditional code. All the fancy
desugaring logic is consolidated in `DerivationBuildingGoal`.

We should better share the pulled-out logic with `nix-shell`/`nix
develop`, which would fill in some missing features, arguably fixing
bugs.
This commit is contained in:
John Ericson 2025-08-18 18:08:35 -04:00
parent e3c74f5a13
commit 1d3ddb21fa
3 changed files with 38 additions and 33 deletions
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30
src/libstore/build/derivation-building-goal.cc
View file

@ -677,7 +677,7 @@ Goal::Co DerivationBuildingGoal::tryToBuild()
auto * localStoreP = dynamic_cast<LocalStore *>(&worker.store);
assert(localStoreP);
decltype(DerivationBuilderParams::extraEnv) extraEnv;
decltype(DerivationBuilderParams::finalEnv) finalEnv;
decltype(DerivationBuilderParams::extraFiles) extraFiles;
try {
@ -685,19 +685,41 @@ Goal::Co DerivationBuildingGoal::tryToBuild()
auto json = drv->structuredAttrs->prepareStructuredAttrs(
worker.store, *drvOptions, inputPaths, drv->outputs);
extraEnv.insert_or_assign(
finalEnv.insert_or_assign(
"NIX_ATTRS_SH_FILE",
DerivationBuilderParams::EnvEntry{
.nameOfPassAsFile = ".attrs.sh",
.value = StructuredAttrs::writeShell(json),
});
extraEnv.insert_or_assign(
finalEnv.insert_or_assign(
"NIX_ATTRS_JSON_FILE",
DerivationBuilderParams::EnvEntry{
.nameOfPassAsFile = ".attrs.json",
.value = json.dump(),
});
} else {
/* In non-structured mode, set all bindings either directory in the
environment or via a file, as specified by
`DerivationOptions::passAsFile`. */
for (auto & [envName, envValue] : drv->env) {
if (drvOptions->passAsFile.find(envName) == drvOptions->passAsFile.end()) {
finalEnv.insert_or_assign(
envName,
DerivationBuilderParams::EnvEntry{
.nameOfPassAsFile = std::nullopt,
.value = envValue,
});
} else {
auto hash = hashString(HashAlgorithm::SHA256, envName);
finalEnv.insert_or_assign(
envName + "Path",
DerivationBuilderParams::EnvEntry{
.nameOfPassAsFile = ".attr-" + hash.to_string(HashFormat::Nix32, false),
.value = envValue,
});
}
}
/* Handle exportReferencesGraph(), if set. */
for (auto & [fileName, storePaths] : drvOptions->getParsedExportReferencesGraph(worker.store)) {
/* Write closure info to <fileName>. */
@ -726,7 +748,7 @@ Goal::Co DerivationBuildingGoal::tryToBuild()
*drvOptions,
inputPaths,
initialOutputs,
std::move(extraEnv),
std::move(finalEnv),
std::move(extraFiles),
});
}

8
src/libstore/include/nix/store/build/derivation-builder.hh
View file

@ -74,13 +74,13 @@ struct DerivationBuilderParams
};
/**
* Extra environment variables to additionally set, possibly
* The final environment variables to additionally set, possibly
* indirectly via a file.
*
* This is used by the caller to desugar the "structured attrs"
* mechanism, so `DerivationBuilder` doesn't need to know about it.
*/
std::map<std::string, EnvEntry, std::less<>> extraEnv;
std::map<std::string, EnvEntry, std::less<>> finalEnv;
/**
* Inserted in the temp dir, but no file names placed in env, unlike
@ -96,7 +96,7 @@ struct DerivationBuilderParams
const DerivationOptions & drvOptions,
const StorePathSet & inputPaths,
std::map<std::string, InitialOutput> & initialOutputs,
std::map<std::string, EnvEntry, std::less<>> extraEnv,
std::map<std::string, EnvEntry, std::less<>> finalEnv,
StringMap extraFiles)
: drvPath{drvPath}
, buildResult{buildResult}
@ -105,7 +105,7 @@ struct DerivationBuilderParams
, inputPaths{inputPaths}
, initialOutputs{initialOutputs}
, buildMode{buildMode}
, extraEnv{std::move(extraEnv)}
, finalEnv{std::move(finalEnv)}
, extraFiles{std::move(extraFiles)}
{
}

33
src/libstore/unix/build/derivation-builder.cc
View file

@ -1016,37 +1016,20 @@ void DerivationBuilderImpl::initEnv()
/* The maximum number of cores to utilize for parallel building. */
env["NIX_BUILD_CORES"] = fmt("%d", settings.buildCores ? settings.buildCores : settings.getDefaultCores());
auto writeEnv = [&](const std::string & envVarName, const std::string & fileName, const std::string & value) {
writeBuilderFile(fileName, rewriteStrings(value, inputRewrites));
env[envVarName] = tmpDirInSandbox() + "/" + fileName;
};
/* In non-structured mode, set all bindings either directory in the
environment or via a file, as specified by
`DerivationOptions::passAsFile`. */
if (!drv.structuredAttrs) {
for (auto & i : drv.env) {
if (drvOptions.passAsFile.find(i.first) == drvOptions.passAsFile.end()) {
env[i.first] = i.second;
} else {
auto hash = hashString(HashAlgorithm::SHA256, i.first);
std::string fn = ".attr-" + hash.to_string(HashFormat::Nix32, false);
writeEnv(i.first + "Path", fn, i.second);
}
}
}
/* Do this with or without structured attrs --- actually, this is
used to desugar structured attrs. */
for (const auto & [name, info] : extraEnv) {
/* Write the final environment. Note that this is intentionally
*not* `drv.env`, because we've desugared things like like
"passAFile", "expandReferencesGraph", structured attrs, etc. */
for (const auto & [name, info] : finalEnv) {
if (info.nameOfPassAsFile) {
writeEnv(name, *info.nameOfPassAsFile, info.value);
auto & fileName = *info.nameOfPassAsFile;
writeBuilderFile(fileName, rewriteStrings(info.value, inputRewrites));
env[name] = tmpDirInSandbox() + "/" + fileName;
} else {
env[name] = info.value;
}
}
/* Add extra files, analogous to `extraEnv` */
/* Add extra files, similar to `finalEnv` */
for (const auto & [fileName, value] : extraFiles) {
writeBuilderFile(fileName, value);
}