From 38a73203a4b304cb0987d4b32a17f7d2137575a4 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Fri, 27 Jun 2025 20:02:18 +0200
Subject: [PATCH] Fix eval caching for path flakes

This fix is somewhat hacky since the accessor/input fingerprint
situation is a bit of a mess.
---
 src/libfetchers/fetchers.cc       | 2 ++
 tests/functional/flakes/flakes.sh | 1 +
 2 files changed, 3 insertions(+)

diff --git a/src/libfetchers/fetchers.cc b/src/libfetchers/fetchers.cc
index d91f24b6a..4d2d66a72 100644
--- a/src/libfetchers/fetchers.cc
+++ b/src/libfetchers/fetchers.cc
@@ -354,6 +354,8 @@ std::pair<ref<SourceAccessor>, Input> Input::getAccessorUnchecked(ref<Store> sto
 
     if (!accessor->fingerprint)
         accessor->fingerprint = result.getFingerprint(store);
+    else
+        result.cachedFingerprint = accessor->fingerprint;
 
     return {accessor, std::move(result)};
 }
diff --git a/tests/functional/flakes/flakes.sh b/tests/functional/flakes/flakes.sh
index ec5cc9c53..cfd204569 100755
--- a/tests/functional/flakes/flakes.sh
+++ b/tests/functional/flakes/flakes.sh
@@ -374,6 +374,7 @@ nix build -o $TEST_ROOT/result git+file://$flakeGitBare
 mkdir -p $flake5Dir
 writeDependentFlake $flake5Dir
 nix flake lock path://$flake5Dir
+[[ "$(nix flake metadata path://$flake5Dir --json | jq -r .fingerprint)" != null ]]
 
 # Test tarball flakes.
 tar cfz $TEST_ROOT/flake.tar.gz -C $TEST_ROOT flake5