[PATCH v2] scripts: git-resolve: ignore non-commit objects

[Hamdy Abou El Anein <info@daylightlinux.ch>]

From: Hamdy Abou El Anein <hamdy.aea@protonmail.com>

git rev-parse --disambiguate lists objects of every type. A unique blob
or tree prefix is therefore returned successfully as a commit ID. Such
an ID cannot be used as a commit reference or Fixes tag.

Filter the candidates by object type before deciding whether the prefix
is unique or looking up its subject.

Tested in a temporary Git repository: a real commit prefix resolves to
its full ID, while blob and tree prefixes produce the command-line
error.

AI assistance: ChatGPT/Codex identified the issue and prepared the
change, commit message and executable regression tests.

Fixes: 7ae52a3d7f51 ("scripts: Add git-resolve tool for full SHA-1 resolution")

Signed-off-by: Hamdy Abou El Anein <hamdy.aea@protonmail.com>
---
 scripts/git-resolve.sh | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/scripts/git-resolve.sh b/scripts/git-resolve.sh
index e9b5940c0f28..7d14cf279e86 100755
--- a/scripts/git-resolve.sh
+++ b/scripts/git-resolve.sh
@@ -49,7 +49,9 @@ git_resolve_commit() {
 
 	# Get all possible matching commit IDs
 	local matches
-	readarray -t matches < <(git rev-parse --disambiguate="$commit_id" 2>/dev/null)
+	readarray -t matches < <(git rev-parse --disambiguate="$commit_id" 2>/dev/null |
+		git cat-file --batch-check='%(objectname) %(objecttype)' |
+		awk '$2 == "commit" { print $1 }')
 
 	# Return immediately if we have exactly one match
 	if [ ${#matches[@]} -eq 1 ]; then
@@ -191,7 +193,9 @@ fi
 # Skip validation in force mode
 if [ -z "$force" ]; then
 	# Validate that the first argument matches at least one git commit
-	if [ "$(git rev-parse --disambiguate="$1" 2>/dev/null | wc -l)" -eq 0 ]; then
+	if [ "$(git rev-parse --disambiguate="$1" 2>/dev/null |
+		git cat-file --batch-check='%(objectname) %(objecttype)' |
+		awk '$2 == "commit" { count++ } END { print count + 0 }')" -eq 0 ]; then
 		echo "Error: '$1' does not match any git commit"
 		exit 1
 	fi
-- 
2.56.0