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Track attributes in nix flake check #14321

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Merged
merged 2 commits into from
Nov 10, 2025
+55 −5
Merged

Track attributes in nix flake check #14321

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a38c7eb
Print failing attribute paths in nix flake check
roberth Oct 21, 2025
d4fd5c2
Remove "(ignored)" from errors in nix flake check --keep-going
roberth Oct 21, 2025
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39 changes: 34 additions & 5 deletions src/nix/flake.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -367,7 +367,7 @@ struct CmdFlakeCheck : FlakeCommand
throw;
} catch (Error & e) {
if (settings.keepGoing) {
ignoreExceptionExceptInterrupt();
logError(e.info());
hasErrors = true;
} else
throw;
Expand Down Expand Up @@ -423,7 +423,7 @@ struct CmdFlakeCheck : FlakeCommand
return std::nullopt;
};

std::vector<DerivedPath> drvPaths;
std::map<DerivedPath, std::vector<AttrPath>> attrPathsByDrv;

auto checkApp = [&](const std::string & attrPath, Value & v, const PosIdx pos) {
try {
Expand Down Expand Up @@ -621,7 +621,13 @@ struct CmdFlakeCheck : FlakeCommand
.drvPath = makeConstantStorePathRef(*drvPath),
.outputs = OutputsSpec::All{},
};
drvPaths.push_back(std::move(path));

// Build and store the attribute path for error reporting
AttrPath attrPath;
attrPath.push_back(AttrName(state->symbols.create(name)));
attrPath.push_back(AttrName(attr.name));
attrPath.push_back(AttrName(attr2.name));
attrPathsByDrv[path].push_back(std::move(attrPath));
}
}
}
Expand Down Expand Up @@ -785,7 +791,9 @@ struct CmdFlakeCheck : FlakeCommand
});
}

if (build && !drvPaths.empty()) {
if (build && !attrPathsByDrv.empty()) {
auto keys = std::views::keys(attrPathsByDrv);
std::vector<DerivedPath> drvPaths(keys.begin(), keys.end());
// TODO: This filtering of substitutable paths is a temporary workaround until
// https://github.com/NixOS/nix/issues/5025 (union stores) is implemented.
//
Expand All @@ -811,7 +819,28 @@ struct CmdFlakeCheck : FlakeCommand
}

Activity act(*logger, lvlInfo, actUnknown, fmt("running %d flake checks", toBuild.size()));
store->buildPaths(toBuild);
auto results = store->buildPathsWithResults(toBuild);

// Report build failures with attribute paths
for (auto & result : results) {
if (auto * failure = result.tryGetFailure()) {
auto it = attrPathsByDrv.find(result.path);
if (it != attrPathsByDrv.end() && !it->second.empty()) {
for (auto & attrPath : it->second) {
auto attrPathStr = showAttrPath(state->symbols, attrPath);
reportError(Error(
"failed to build attribute '%s', build of '%s' failed: %s",
attrPathStr,
result.path.to_string(*store),
failure->errorMsg));
Comment on lines +831 to +835
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@roberth roberth Oct 22, 2025 •
edited
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Not a blocker, idea:
Suggest nix check <flakeref>.<attrPathStr>

}
} else {
// Derivation has no attribute path (e.g., a build dependency)
reportError(
Error("build of '%s' failed: %s", result.path.to_string(*store), failure->errorMsg));
}
}
}
}
if (hasErrors)
throw Error("some errors were encountered during the evaluation");
Expand Down
21 changes: 21 additions & 0 deletions tests/functional/flakes/check.sh
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Expand Up @@ -192,3 +192,24 @@ EOF
# shellcheck disable=SC2015
checkRes=$(nix flake check "$flakeDir" 2>&1 && fail "nix flake check should have failed" || true)
echo "$checkRes" | grepQuiet -E "builder( for .*)? failed with exit code 1"

# Test that attribute paths are shown in error messages
cat > "$flakeDir"/flake.nix <<EOF
{
outputs = { self }: with import ./config.nix; {
checks.${system}.failingCheck = mkDerivation {
name = "failing-check";
buildCommand = "echo 'This check fails'; exit 1";
};
checks.${system}.anotherFailingCheck = mkDerivation {
name = "another-failing-check";
buildCommand = "echo 'This also fails'; exit 1";
};
};
}
EOF

# shellcheck disable=SC2015
checkRes=$(nix flake check --keep-going "$flakeDir" 2>&1 && fail "nix flake check should have failed" || true)
echo "$checkRes" | grepQuiet "checks.${system}.failingCheck"
echo "$checkRes" | grepQuiet "checks.${system}.anotherFailingCheck"
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