review

- avoid extra calls via _date() in one more case.

Author: Byron

git/_backend.py

@@ -245,8 +245,8 @@ def object_metadata(command: Any, oid: str, kind: str) -> Any:
             else ((data.tagger, result["tagger"]),)
         )
         for raw, signature in signatures:
-            # Gix reads a time zone of 0 when other fields follow the date (GIX-34).
-            if signature is not None and not raw.endswith(b"> " + _date(signature)):
+            # Gix reads a time zone of 0 with trailing fields (GIX-34); accept either UTC sign.
+            if signature is not None and not raw.replace(b" -0000", b" +0000").endswith(b"> " + _date(signature)):
                 raise _Unsupported("signature trailing fields (GIX-34)")
     except _Unsupported as exc:
         return _fallback(kind + ".decode", str(exc))

test/test_commit.py

@@ -671,6 +671,32 @@ def test_deserialization_reads_date_after_email(self):
                     key = (kind + ".decode", "CLI: signature trailing fields (GIX-34)")
                     self.assertEqual(_backend.statistics().get(key, 0), before.get(key, 0) + 1)
 
+    def test_deserialization_negative_zero_offset_stays_native(self):
+        with fixture_repo("commit.sh", "zero-offset") as repo:
+            root = Path(repo.working_dir).parent
+            oid = (root / "object-id").read_text().strip()
+            tag_oid = (root / "tag-id").read_text().strip()
+            repo.git.fsck("--strict", oid, tag_oid)
+            self.assertTrue(repo.git.cat_file("-p", tag_oid).split("\n")[3].endswith(" -0000"))
+            self.assertEqual(
+                repo.git.show("--no-patch", "--format=%ad%n%cd", "--date=raw", oid, "--"),
+                "1112591163 +0000\n1112591163 +0000",
+            )
+            self.assertEqual(repo.git.for_each_ref("--format=%(taggerdate:raw)", "refs/tags/v1"), "1112591163 +0000")
+            before = _backend.statistics()
+            cmt = Commit(repo, bytes.fromhex(oid))
+            self.assertEqual((cmt.authored_date, cmt.author_tz_offset), (1112591163, 0))
+            self.assertEqual((cmt.committed_date, cmt.committer_tz_offset), (1112591163, 0))
+            tag = TagObject(repo, bytes.fromhex(tag_oid))
+            self.assertEqual((tag.tagged_date, tag.tagger_tz_offset), (1112591163, 0))
+            if _backend.name == "gix":
+                after = _backend.statistics()
+                for kind in ("commit", "tag"):
+                    key = (kind + ".decode", "native")
+                    self.assertEqual(after.get(key, 0), before.get(key, 0) + 1)
+                key = ("Git.execute", "CLI process")
+                self.assertEqual(after.get(key, 0), before.get(key, 0))
+
     def test_identity_cannot_alter_headers(self):
         """A name or email must not add header lines or present another identity."""
         with fixture_repo("commit.sh", "tree", write=True) as rw_repo:

tests/fixtures/commit.sh

@@ -47,17 +47,19 @@ case "$1" in
     raw)
         git hash-object --literally -w -t commit "$2" > ../object-id
         ;;
-    trailing-date)
+    trailing-date|zero-offset)
+        date='1112591163 +0200 1700000000 -0500'
+        if [ "$1" = zero-offset ]; then date='1112591163 -0000'; fi
         tree=$(git mktree </dev/null)
         {
             printf 'tree %s\n' "$tree"
-            printf 'author A <a@example.com> 1112591163 +0200 1700000000 -0500\n'
-            printf 'committer C <c@example.com> 1112591163 +0200 1700000000 -0500\n'
+            printf 'author A <a@example.com> %s\n' "$date"
+            printf 'committer C <c@example.com> %s\n' "$date"
             printf '\nmessage\n'
         } | git hash-object --literally -w -t commit --stdin > ../object-id
         {
             printf 'object %s\ntype commit\ntag v1\n' "$(cat ../object-id)"
-            printf 'tagger T <t@example.com> 1112591163 +0200 1700000000 -0500\n'
+            printf 'tagger T <t@example.com> %s\n' "$date"
             printf '\nmessage\n'
         } | git hash-object --literally -w -t tag --stdin > ../tag-id
         git update-ref refs/tags/v1 "$(cat ../tag-id)"