git_refs: read refs via git plumbing for files/reftable

Replace direct `packed-refs` file parsing with `git for-each-ref` plumbing to support both `files` and `reftable` backends. Bug: 476209856 Change-Id: I2ad8ff8f3382426600f15370c997f9bc17165485 Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/550401 Commit-Queue: Gavin Mak <gavinmak@google.com> Reviewed-by: Mike Frysinger <vapier@google.com> Tested-by: Gavin Mak <gavinmak@google.com>
2026-05-09 12:29:33 +00:00 · 2026-02-06 14:55:34 -08:00
parent 551087cd98
commit 67881c0c3b
4 changed files with 237 additions and 62 deletions
@@ -0,0 +1,99 @@
+# Copyright (C) 2026 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unittests for the git_refs.py module."""
+
+import os
+from pathlib import Path
+import subprocess
+
+import pytest
+import utils_for_test
+
+import git_refs
+
+
+def _run(repo, *args):
+    return subprocess.run(
+        ["git", "-C", repo, *args],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        encoding="utf-8",
+        check=True,
+    ).stdout.strip()
+
+
+def _init_repo(tmp_path, reftable=False):
+    repo = os.path.join(tmp_path, "repo")
+    ref_format = "reftable" if reftable else "files"
+    utils_for_test.init_git_tree(repo, ref_format=ref_format)
+
+    Path(os.path.join(repo, "a")).write_text("1")
+    _run(repo, "add", "a")
+    _run(repo, "commit", "-q", "-m", "init")
+    return repo
+
+
+@pytest.mark.parametrize("reftable", [False, True])
+def test_reads_refs(tmp_path, reftable):
+    if reftable and not utils_for_test.supports_reftable():
+        pytest.skip("reftable not supported")
+
+    repo = _init_repo(tmp_path, reftable=reftable)
+    gitdir = os.path.join(repo, ".git")
+    refs = git_refs.GitRefs(gitdir)
+
+    branch = _run(repo, "symbolic-ref", "--short", "HEAD")
+    head = _run(repo, "rev-parse", "HEAD")
+    assert refs.symref("HEAD") == f"refs/heads/{branch}"
+    assert refs.get("HEAD") == head
+    assert refs.get(f"refs/heads/{branch}") == head
+
+
+@pytest.mark.parametrize("reftable", [False, True])
+def test_updates_when_refs_change(tmp_path, reftable):
+    if reftable and not utils_for_test.supports_reftable():
+        pytest.skip("reftable not supported")
+
+    repo = _init_repo(tmp_path, reftable=reftable)
+    gitdir = os.path.join(repo, ".git")
+    refs = git_refs.GitRefs(gitdir)
+
+    head = _run(repo, "rev-parse", "HEAD")
+    assert refs.get("refs/heads/topic") == ""
+    _run(repo, "branch", "topic")
+    assert refs.get("refs/heads/topic") == head
+    _run(repo, "branch", "-D", "topic")
+    assert refs.get("refs/heads/topic") == ""
+
+
+@pytest.mark.skipif(
+    not utils_for_test.supports_refs_migrate(),
+    reason="git refs migrate reftable support is required for this test",
+)
+def test_updates_when_storage_backend_toggles(tmp_path):
+    repo = _init_repo(tmp_path, reftable=False)
+    gitdir = os.path.join(repo, ".git")
+    refs = git_refs.GitRefs(gitdir)
+
+    head = _run(repo, "rev-parse", "HEAD")
+    assert refs.get("refs/heads/reftable-branch") == ""
+    _run(repo, "refs", "migrate", "--ref-format=reftable")
+    _run(repo, "branch", "reftable-branch")
+    assert refs.get("refs/heads/reftable-branch") == head
+
+    assert refs.get("refs/heads/files-branch") == ""
+    _run(repo, "refs", "migrate", "--ref-format=files")
+    _run(repo, "branch", "files-branch")
+    assert refs.get("refs/heads/files-branch") == head