feat(tvix/derivation): add `path_with_references` r/5737

This allows the calculation of a store path for a plain string that
potentially contains references. These paths are used for
`builtins.toFile` (and potentially other features of C++ Nix).

Change-Id: Ic507c7f264f362b5e6e628255869e5a4fbe4d788
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7906
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 36 insertions, 0 deletions

diff --git a/tvix/derivation/src/tests/mod.rs b/tvix/derivation/src/tests/mod.rs
index 5dd60284f05c..ce39afdd2854 100644
--- a/tvix/derivation/src/tests/mod.rs
+++ b/tvix/derivation/src/tests/mod.rs
@@ -305,3 +305,39 @@ fn output_path_construction() {
             .expect("must succeed")
     );
 }
+
+#[test]
+fn path_with_zero_references() {
+    // This hash should match `builtins.toFile`, e.g.:
+    //
+    // nix-repl> builtins.toFile "foo" "bar"
+    // "/nix/store/vxjiwkjkn7x4079qvh1jkl5pn05j2aw0-foo"
+
+    let store_path = crate::path_with_references("foo", "bar", vec![])
+        .expect("path_with_references() should succeed");
+
+    assert_eq!(
+        store_path.to_absolute_path().as_str(),
+        "/nix/store/vxjiwkjkn7x4079qvh1jkl5pn05j2aw0-foo"
+    );
+}
+
+#[test]
+fn path_with_non_zero_references() {
+    // This hash should match:
+    //
+    // nix-repl> builtins.toFile "baz" "${builtins.toFile "foo" "bar"}"
+    // "/nix/store/5xd714cbfnkz02h2vbsj4fm03x3f15nf-baz"
+
+    let inner = crate::path_with_references("foo", "bar", vec![])
+        .expect("path_with_references() should succeed");
+    let inner_path = inner.to_absolute_path();
+
+    let outer = crate::path_with_references("baz", &inner_path, vec![inner_path.as_str()])
+        .expect("path_with_references() should succeed");
+
+    assert_eq!(
+        outer.to_absolute_path().as_str(),
+        "/nix/store/5xd714cbfnkz02h2vbsj4fm03x3f15nf-baz"
+    );
+}