Skip to content

builtins.hashString: Devirtualize lazy paths, and re-enable lazy trees tests #360

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
edolstra merged 3 commits into from
Feb 20, 2026
+24 −4
Merged

builtins.hashString: Devirtualize lazy paths, and re-enable lazy trees tests #360

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
823f756
builtins.hashString: Devirtualize lazy paths
edolstra Feb 20, 2026
90bec9c
Re-enable lazy trees tests
edolstra Feb 20, 2026
5d6ab84
Fix `nix run` on an app with lazy trees enabled
edolstra Feb 20, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 5 additions & 0 deletions ci/gha/tests/default.nix
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,11 @@ rec {
'';
repl-completion = pkgs.callPackage ../../../tests/repl-completion.nix { inherit (packages') nix; };

lazyTrees = nixComponents.nix-functional-tests.override {
pname = "nix-lazy-trees-tests";
lazyTrees = true;
};

/**
Checks for our packaging expressions.
This shouldn't build anything significant; just check that things
Expand Down
5 changes: 3 additions & 2 deletions src/libexpr/primops.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4729,8 +4729,9 @@ static void prim_hashString(EvalState & state, const PosIdx pos, Value ** args,
state.error<EvalError>("unknown hash algorithm '%1%'", algo).atPos(pos).debugThrow();

NixStringContext context; // discarded
auto s =
state.forceString(*args[1], context, pos, "while evaluating the second argument passed to builtins.hashString");
auto s = state.devirtualize(
state.forceString(*args[1], context, pos, "while evaluating the second argument passed to builtins.hashString"),
context);

v.mkString(hashString(*ha, s).to_string(HashFormat::Base16, false), state.mem);
}
Expand Down
4 changes: 2 additions & 2 deletions src/nix/app.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -90,7 +90,7 @@ UnresolvedApp InstallableValue::toApp(EvalState & state)
},
[&](const NixStringContextElem::Opaque & o) -> DerivedPath {
return DerivedPath::Opaque{
.path = o.path,
.path = state.devirtualize(o.path),
};
},
[&](const NixStringContextElem::Path & p) -> DerivedPath {
Expand All @@ -102,7 +102,7 @@ UnresolvedApp InstallableValue::toApp(EvalState & state)

return UnresolvedApp{App{
.context = std::move(context2),
.program = program,
.program = state.devirtualize(program, context),
}};
}

Expand Down
14 changes: 14 additions & 0 deletions tests/functional/fetchGit.sh
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -363,3 +363,17 @@ rm "$TEST_ROOT"/flake/flake.lock
nix eval "path:$TEST_ROOT/flake"#isModern
nix eval --nix-219-compat "path:$TEST_ROOT/flake"#isModern
[[ $(jq -r .nodes.eol.locked.narHash < "$TEST_ROOT"/flake/flake.lock) = "$newHash" ]]


# Test that builtins.hashString devirtualizes lazy paths (https://github.com/DeterminateSystems/determinate/issues/160).
hashStringRepo="$TEST_ROOT/hashString"
createGitRepo "$hashStringRepo"
echo hello > "$hashStringRepo"/hello
git -C "$hashStringRepo" add hello
git -C "$hashStringRepo" commit -m 'Initial'
hashStringRev=$(git -C "$hashStringRepo" rev-parse HEAD)

hash1=$(nix eval --lazy-trees --raw --expr "builtins.hashString \"sha256\" (toString ((builtins.fetchGit { url = file://$hashStringRepo; rev = \"$hashStringRev\"; })))")
hash2=$(nix eval --lazy-trees --raw --expr "builtins.hashString \"sha256\" (toString ((builtins.fetchGit { url = file://$hashStringRepo; rev = \"$hashStringRev\"; })))")

[[ "$hash1" = "$hash2" ]]
Loading