From 1564c8f9d90017ef446815d8aadbf28aaf5a5e81 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Tue, 1 Apr 2025 18:37:21 +0200
Subject: [PATCH] Fix missing file error messages from 'import'

---
 src/libutil/mounted-source-accessor.cc  |  6 ++++++
 tests/functional/flakes/source-paths.sh | 19 +++++++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/libutil/mounted-source-accessor.cc b/src/libutil/mounted-source-accessor.cc
index e1442d686..c21a71047 100644
--- a/src/libutil/mounted-source-accessor.cc
+++ b/src/libutil/mounted-source-accessor.cc
@@ -23,6 +23,12 @@ struct MountedSourceAccessorImpl : MountedSourceAccessor
         return accessor->readFile(subpath);
     }
 
+    Stat lstat(const CanonPath & path) override
+    {
+        auto [accessor, subpath] = resolve(path);
+        return accessor->lstat(subpath);
+    }
+
     std::optional<Stat> maybeLstat(const CanonPath & path) override
     {
         auto [accessor, subpath] = resolve(path);
diff --git a/tests/functional/flakes/source-paths.sh b/tests/functional/flakes/source-paths.sh
index 10b834bc8..e82d27c81 100644
--- a/tests/functional/flakes/source-paths.sh
+++ b/tests/functional/flakes/source-paths.sh
@@ -14,6 +14,8 @@ cat > "$repo/flake.nix" <<EOF
     x = 1;
     y = assert false; 1;
     z = builtins.readFile ./foo;
+    a = import ./foo;
+    b = import ./dir;
   };
 }
 EOF
@@ -32,11 +34,24 @@ expectStderr 1 nix eval "git+file://$repo?ref=master#y" | grepQuiet "at «git+fi
 
 expectStderr 1 nix eval "$repo#z" | grepQuiet "error: path '/foo' does not exist in Git repository \"$repo\""
 expectStderr 1 nix eval "git+file://$repo?ref=master#z" | grepQuiet "error: '«git+file://$repo?ref=master&rev=.*»/foo' does not exist"
+expectStderr 1 nix eval "$repo#a" | grepQuiet "error: path '/foo' does not exist in Git repository \"$repo\""
 
-echo foo > "$repo/foo"
+echo 123 > "$repo/foo"
 
 expectStderr 1 nix eval "$repo#z" | grepQuiet "error: File 'foo' in the repository \"$repo\" is not tracked by Git."
+expectStderr 1 nix eval "$repo#a" | grepQuiet "error: File 'foo' in the repository \"$repo\" is not tracked by Git."
 
 git -C "$repo" add "$repo/foo"
 
-[[ $(nix eval --raw "$repo#z") = foo ]]
+[[ $(nix eval --raw "$repo#z") = 123 ]]
+
+expectStderr 1 nix eval "$repo#b" | grepQuiet "error: path '/dir' does not exist in Git repository \"$repo\""
+
+mkdir -p $repo/dir
+echo 456 > $repo/dir/default.nix
+
+expectStderr 1 nix eval "$repo#b" | grepQuiet "error: File 'dir' in the repository \"$repo\" is not tracked by Git."
+
+git -C "$repo" add "$repo/dir/default.nix"
+
+[[ $(nix eval "$repo#b") = 456 ]]