From 4ea5cb38325c728bb8f96f57b185f3c25275b3a0 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Mon, 12 May 2025 17:27:05 +0200
Subject: [PATCH] Fix emitting narHash in lock files when lazy trees are
 disabled

---
 src/libexpr/paths.cc              | 2 +-
 tests/functional/fetchGit.sh      | 2 +-
 tests/functional/flakes/flakes.sh | 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/libexpr/paths.cc b/src/libexpr/paths.cc
index da1408e9b..3aaca2328 100644
--- a/src/libexpr/paths.cc
+++ b/src/libexpr/paths.cc
@@ -77,7 +77,7 @@ StorePath EvalState::mountInput(
 
     storeFS->mount(CanonPath(store->printStorePath(storePath)), accessor);
 
-    if (requireLockable && !input.isLocked() && !input.getNarHash()) {
+    if (requireLockable && (!settings.lazyTrees || !input.isLocked()) && !input.getNarHash()) {
         auto narHash = accessor->hashPath(CanonPath::root);
         input.attrs.insert_or_assign("narHash", narHash.to_string(HashFormat::SRI, true));
     }
diff --git a/tests/functional/fetchGit.sh b/tests/functional/fetchGit.sh
index 6fc8ca8b0..5e5e8e61f 100755
--- a/tests/functional/fetchGit.sh
+++ b/tests/functional/fetchGit.sh
@@ -292,7 +292,7 @@ path11=$(nix eval --impure --raw --expr "(builtins.fetchGit ./.).outPath")
 empty="$TEST_ROOT/empty"
 git init "$empty"
 
-emptyAttrs='{ lastModified = 0; lastModifiedDate = "19700101000000"; rev = "0000000000000000000000000000000000000000"; revCount = 0; shortRev = "0000000"; submodules = false; }'
+emptyAttrs='{ lastModified = 0; lastModifiedDate = "19700101000000"; narHash = "sha256-pQpattmS9VmO3ZIQUFn66az8GSmB4IvYhTTCFn6SUmo="; rev = "0000000000000000000000000000000000000000"; revCount = 0; shortRev = "0000000"; submodules = false; }'
 
 [[ $(nix eval --impure --expr "builtins.removeAttrs (builtins.fetchGit $empty) [\"outPath\"]") = $emptyAttrs ]]
 
diff --git a/tests/functional/flakes/flakes.sh b/tests/functional/flakes/flakes.sh
index 7ec438d74..fd31c4c4f 100755
--- a/tests/functional/flakes/flakes.sh
+++ b/tests/functional/flakes/flakes.sh
@@ -161,6 +161,7 @@ expect 1 nix build -o "$TEST_ROOT/result" "$flake2Dir#bar" --no-update-lock-file
 nix build -o "$TEST_ROOT/result" "$flake2Dir#bar" --commit-lock-file
 [[ -e "$flake2Dir/flake.lock" ]]
 [[ -z $(git -C "$flake2Dir" diff main || echo failed) ]]
+[[ -n $(jq .nodes.flake1.locked.narHash < "$flake2Dir/flake.lock") ]]
 
 # Rerunning the build should not change the lockfile.
 nix build -o "$TEST_ROOT/result" "$flake2Dir#bar"