"""Tests for self-update diagnostics (api/updates.py)."""
from unittest.mock import MagicMock, patch

import api.updates as updates


def _fake_git_for_release_fetch_failure(args, cwd, timeout=10):
    if args == ['diff-index', '--quiet', 'HEAD', '--']:
        return '', True  # clean tree
    if args == ['fetch', 'origin', '--tags', '--force']:
        return 'would clobber existing tag v0.50.294', False
    if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
        return 'v0.51.106\nv0.51.103', True
    if args == ['describe', '--tags', '--abbrev=0']:
        return 'v0.51.103', True
    if args == ['merge-base', '--is-ancestor', 'v0.51.106', 'HEAD']:
        return '', False
    if args == ['merge-base', '--is-ancestor', 'HEAD', 'v0.51.106']:
        return '', True
    if args == ['remote', 'get-url', 'origin']:
        return 'https://github.com/nesquena/hermes-webui.git', True
    raise AssertionError(f'unexpected git args: {args!r}')


def test_check_repo_reports_release_gap_even_when_tag_fetch_fails(tmp_path):
    """A tag fetch error must not collapse the UI state to "up to date"."""
    (tmp_path / '.git').mkdir()
    with patch.object(updates, '_run_git', side_effect=_fake_git_for_release_fetch_failure):
        info = updates._check_repo(tmp_path, 'webui')

    assert info is not None
    assert info['behind'] == 1
    assert info['current_version'] == 'v0.51.103'
    assert info['latest_version'] == 'v0.51.106'
    assert info['stale_check'] is True
    assert 'would clobber existing tag' in info['error']
    # Issue #4085: the dirty flag must ride along on every payload shape.
    # The mock returns ('', True) for the dirty probe, so the tree is clean.
    assert info['dirty'] is False


def test_check_repo_redacts_credentialed_fetch_failure(tmp_path):
    """Update-check errors must not expose credentials from git remotes."""
    (tmp_path / '.git').mkdir()
    secret = 'ghp_' + 'A' * 36
    raw_error = (
        "fatal: unable to access "
        f"'https://ash:{secret}@github.com/private/repo.git/': "
        "Authentication failed"
    )

    def fake_git(args, cwd, timeout=10):
        if args == ['diff-index', '--quiet', 'HEAD', '--']:
            return '', True
        if args == ['fetch', 'origin', '--tags', '--force']:
            return raw_error, False
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return '', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        info = updates._check_repo(tmp_path, 'webui')

    assert info is not None
    assert info['behind'] is None
    assert info['stale_check'] is True
    assert secret not in info['error']
    assert 'ash:' not in info['error']
    assert '<redacted>' in info['error']
    assert 'Authentication failed' in info['error']


def test_check_repo_fetch_failure_without_tags_is_not_up_to_date(tmp_path):
    """If release tags cannot be read, behind is unknown rather than zero."""
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['diff-index', '--quiet', 'HEAD', '--']:
            return '', True
        if args == ['fetch', 'origin', '--tags', '--force']:
            return 'network unavailable', False
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return '', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        info = updates._check_repo(tmp_path, 'webui')

    assert info is not None
    assert info['behind'] is None
    assert info['stale_check'] is True
    assert info['error'] == 'fetch failed: network unavailable'


def test_check_for_updates_can_skip_agent_repo(tmp_path):
    """Ignoring Agent updates should still check WebUI but avoid touching Agent git."""
    webui_path = tmp_path / 'webui'
    agent_path = tmp_path / 'agent'
    webui_path.mkdir()
    agent_path.mkdir()

    seen = []

    def fake_check_repo(path, name):
        seen.append(name)
        return {'name': name, 'behind': 2 if name == 'webui' else 9}

    cache_defaults = {'webui': None, 'agent': None, 'checked_at': 0, 'include_agent': True}
    with patch.dict(updates._update_cache, cache_defaults, clear=True), \
         patch.object(updates, 'REPO_ROOT', webui_path), \
         patch.object(updates, '_AGENT_DIR', agent_path), \
         patch.object(updates, '_check_repo', side_effect=fake_check_repo):
        result = updates.check_for_updates(force=True, include_agent=False)

    assert seen == ['webui']
    assert result['webui']['behind'] == 2
    assert result['agent'] == {'name': 'agent', 'behind': 0, 'ignored': True}
    assert result['include_agent'] is False


def test_update_cache_is_scoped_by_agent_inclusion(tmp_path):
    """Toggling Agent update checks must not reuse a stale opposite-mode cache."""
    (tmp_path / '.git').mkdir()
    calls = []

    def fake_check_repo(path, name):
        calls.append(name)
        return {'name': name, 'behind': len(calls)}

    with patch.dict(updates._update_cache, {'webui': None, 'agent': None, 'checked_at': 0, 'include_agent': True}, clear=True), \
         patch.object(updates, 'REPO_ROOT', tmp_path), \
         patch.object(updates, '_AGENT_DIR', tmp_path), \
         patch.object(updates, '_check_repo', side_effect=fake_check_repo):
        ignored = updates.check_for_updates(force=True, include_agent=False)
        included = updates.check_for_updates(force=False, include_agent=True)

    assert ignored['agent']['ignored'] is True
    assert included['agent']['name'] == 'agent'
    assert included['agent'].get('ignored') is not True
    assert calls == ['webui', 'webui', 'agent']


def test_run_git_returns_stderr_on_failure(tmp_path):
    """When a git command fails, _run_git should return stderr (not empty string)."""
    with patch('subprocess.run') as mock_run:
        mock_run.return_value = MagicMock(
            returncode=1,
            stdout='',
            stderr="fatal: 'origin/master' does not appear to be a git repository\n",
        )
        out, ok = updates._run_git(['pull', '--ff-only', 'origin/master'], tmp_path)

    assert ok is False
    assert "does not appear to be a git repository" in out


def test_run_git_returns_stdout_when_no_stderr(tmp_path):
    """If stderr is empty on failure, fall back to stdout."""
    with patch('subprocess.run') as mock_run:
        mock_run.return_value = MagicMock(
            returncode=128,
            stdout='Already up to date.',
            stderr='',
        )
        out, ok = updates._run_git(['pull'], tmp_path)

    assert ok is False
    assert 'Already up to date' in out


def test_run_git_returns_exit_code_when_no_output(tmp_path):
    """If both stdout and stderr are empty, report the exit code."""
    with patch('subprocess.run') as mock_run:
        mock_run.return_value = MagicMock(
            returncode=1,
            stdout='',
            stderr='',
        )
        out, ok = updates._run_git(['status'], tmp_path)

    assert ok is False
    assert 'status 1' in out


def test_run_git_uses_utf8_replacement_for_windows_console_output(tmp_path):
    """Git output can contain Unicode even when Windows' active code page cannot."""
    with patch('subprocess.run') as mock_run:
        mock_run.return_value = MagicMock(returncode=0, stdout='v0.51.184\n', stderr=None)

        out, ok = updates._run_git(['describe', '--tags'], tmp_path)

    assert ok is True
    assert out == 'v0.51.184'
    kwargs = mock_run.call_args.kwargs
    assert kwargs['encoding'] == 'utf-8'
    assert kwargs['errors'] == 'replace'


def test_run_git_handles_missing_stdout_after_decode_thread_failure(tmp_path):
    """A subprocess reader failure must not make version detection crash on import."""
    with patch('subprocess.run') as mock_run:
        mock_run.return_value = MagicMock(returncode=0, stdout=None, stderr=None)

        out, ok = updates._run_git(['diff', '--binary', 'HEAD', '--'], tmp_path)

    assert ok is True
    assert out == ''


def test_split_remote_ref_splits_tracking_ref():
    """_split_remote_ref should correctly split origin/branch."""
    assert updates._split_remote_ref('origin/master') == ('origin', 'master')
    assert updates._split_remote_ref('origin/feature/foo') == ('origin', 'feature/foo')
    assert updates._split_remote_ref('master') == (None, 'master')


# ---------------------------------------------------------------------------
# #2756 — Update check fails with "would clobber existing tag" when an
# upstream release tag was moved.
#
# All three fetch-tag call sites in api/updates.py must use --force so the
# WebUI (a release-tracking consumer that never pushes tags) always defers
# to whatever the remote says a release tag points to. Without --force,
# any remote re-tag (e.g. squash-merge that re-points a release tag at a
# new SHA) jams the update path indefinitely.
# ---------------------------------------------------------------------------


def test_check_repo_fetches_tags_with_force(tmp_path):
    """_check_repo must pass --force to git fetch --tags (regression for #2756)."""
    (tmp_path / '.git').mkdir()

    seen_args = []

    def fake_git(args, cwd, timeout=10):
        seen_args.append(args)
        if args == ['diff-index', '--quiet', 'HEAD', '--']:
            return '', True
        if args[:2] == ['fetch', 'origin']:
            # Force a fetch failure path so we don't have to mock the rest of
            # the release/branch logic; the assertion is about the args shape.
            return '', False
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return '', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        updates._check_repo(tmp_path, 'webui')

    fetch_calls = [a for a in seen_args if a[:2] == ['fetch', 'origin']]
    assert fetch_calls, 'expected at least one fetch call'
    for call in fetch_calls:
        assert '--tags' in call, f'fetch should include --tags: {call!r}'
        assert '--force' in call, (
            f'fetch should include --force to recover from remote re-tags '
            f'(see #2756): {call!r}'
        )


def test_apply_force_update_fetches_tags_with_force(tmp_path):
    """apply_force_update must pass --force to git fetch --tags (#2756)."""
    (tmp_path / '.git').mkdir()

    seen_args = []

    def fake_git(args, cwd, timeout=10):
        seen_args.append(args)
        if args[:2] == ['fetch', 'origin']:
            return '', False  # short-circuit; we just want the args shape.
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git), \
         patch.object(updates, 'REPO_ROOT', tmp_path), \
         patch.object(updates, '_restart_blocker_snapshot', return_value={'restart_blocked': False, 'active_streams': 0, 'active_runs': 0}):
        updates.apply_force_update('webui')

    fetch_calls = [a for a in seen_args if a[:2] == ['fetch', 'origin']]
    assert fetch_calls, 'expected at least one fetch call'
    for call in fetch_calls:
        assert '--tags' in call and '--force' in call, (
            f'apply_force_update fetch should be --tags --force (see #2756): {call!r}'
        )


def test_apply_update_fetches_tags_with_force(tmp_path):
    """apply_update must pass --force to git fetch --tags (#2756)."""
    (tmp_path / '.git').mkdir()

    seen_args = []

    def fake_git(args, cwd, timeout=10):
        seen_args.append(args)
        if args[:2] == ['fetch', 'origin']:
            return '', False  # short-circuit on fetch failure.
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git), \
         patch.object(updates, 'REPO_ROOT', tmp_path), \
         patch.object(updates, '_restart_blocker_snapshot', return_value={'restart_blocked': False, 'active_streams': 0, 'active_runs': 0}):
        updates.apply_update('webui')

    fetch_calls = [a for a in seen_args if a[:2] == ['fetch', 'origin']]
    assert fetch_calls, 'expected at least one fetch call'
    for call in fetch_calls:
        assert '--tags' in call and '--force' in call, (
            f'apply_update fetch should be --tags --force (see #2756): {call!r}'
        )


def test_check_repo_recovers_from_remote_retag(tmp_path):
    """End-to-end: a remote-retag scenario should now succeed (#2756).

    Before the fix, `git fetch origin --tags` would return "would clobber
    existing tag v0.51.5" indefinitely. With --force the fetch succeeds and
    the regular up-to-date / behind path runs.
    """
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        # The --force flag makes the fetch succeed even when local tags
        # diverge from remote tags. Refuse to honor a plain --tags fetch
        # (no --force) so the test fails loudly if the regression returns.
        if args == ['fetch', 'origin', '--tags']:
            return (
                ' ! [rejected]        v0.51.5    -> v0.51.5    '
                '(would clobber existing tag)'
            ), False
        if args == ['fetch', 'origin', '--tags', '--force']:
            return '', True
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v0.51.110\nv0.51.109', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v0.51.110', True
        if args == ['describe', '--tags', '--always']:
            return 'v0.51.110', True
        if args == ['remote', 'get-url', 'origin']:
            return 'https://github.com/nesquena/hermes-webui.git', True
        # Branch-check fallback is fine to no-op for this assertion.
        return '', True

    with patch.object(updates, '_run_git', side_effect=fake_git):
        info = updates._check_repo(tmp_path, 'webui')

    assert info is not None
    assert info.get('error') is None, (
        f'expected clean update check, got error: {info.get("error")!r}'
    )
    assert info.get('stale_check') is not True, (
        'fetch with --force should have succeeded, not marked stale'
    )


# ---------------------------------------------------------------------------
# #2653 — Update check reports "Up to date" while the repo is hundreds of
# commits past the latest tag (agent cadence bug).
#
# When current_tag == latest_tag (behind==0 from the release check) but HEAD
# has moved past that tag (git describe --tags --always returns a -N-gSHA
# suffix), _check_repo_release must return None so the branch check runs and
# reports the real commit gap.
# ---------------------------------------------------------------------------


def test_check_repo_release_falls_through_when_head_is_past_tag(tmp_path):
    """_check_repo_release returns None when behind==0 but HEAD is past the tag.

    Simulates the hermes-agent case: latest tag == current tag (v2026.5.16)
    but git describe shows 608 commits past it.  The release check must
    not report 'Up to date'; it should fall through so the branch check
    counts the real gap.
    """
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.16', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v2026.5.16', True
        # HEAD is 608 commits past the tag — describe includes a suffix.
        if args == ['describe', '--tags', '--always']:
            return 'v2026.5.16-608-g1d22b9c2d', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        result = updates._check_repo_release(tmp_path, 'test-repo')

    assert result is None, (
        '_check_repo_release should return None when HEAD is past the latest tag '
        'so the branch check can report the real commit gap (#2653)'
    )


def test_check_repo_release_not_affected_when_head_exactly_on_tag(tmp_path):
    """_check_repo_release works normally when HEAD is exactly on the latest tag."""
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.16\nv2026.5.10', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v2026.5.16', True
        # No -N-gSHA suffix: HEAD is exactly on the tag.
        if args == ['describe', '--tags', '--always']:
            return 'v2026.5.16', True
        if args == ['remote', 'get-url', 'origin']:
            return 'https://github.com/nesquena/hermes-agent.git', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        result = updates._check_repo_release(tmp_path, 'agent')

    assert result is not None
    assert result['behind'] == 0
    assert result['current_version'] == 'v2026.5.16'
    assert result['latest_version'] == 'v2026.5.16'


def test_check_repo_branch_check_runs_for_post_tag_commits(tmp_path):
    """End-to-end: when HEAD is past latest tag, _check_repo uses branch check.

    Mirrors the exact scenario in issue #2653 where Agent: v2026.5.16-593-g...
    was displayed alongside 'Up to date' in Settings.
    """
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['fetch', 'origin', '--tags', '--force']:
            return '', True
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.16', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v2026.5.16', True
        # HEAD is 608 commits past the tag.
        if args == ['describe', '--tags', '--always']:
            return 'v2026.5.16-608-g1d22b9c2d', True
        # Branch-check path follows: rev-parse upstream, default branch, rev-list.
        if args == ['rev-parse', '--abbrev-ref', '@{upstream}']:
            return '', False
        if args == ['symbolic-ref', 'refs/remotes/origin/HEAD']:
            return 'refs/remotes/origin/master', True
        if args[:2] == ['rev-list', '--count']:
            return '608', True
        # merge-base and short SHA lookups for compare URL
        if args[0] == 'merge-base':
            return 'abc1234' * 5, True
        if args[:2] == ['rev-parse', '--short']:
            return 'abc1234', True
        if args == ['remote', 'get-url', 'origin']:
            return 'https://github.com/nesquena/hermes-agent.git', True
        return '', True

    with patch.object(updates, '_run_git', side_effect=fake_git):
        info = updates._check_repo(tmp_path, 'agent')

    assert info is not None
    assert info['behind'] == 608, (
        f"expected behind=608 (branch check result), got {info['behind']!r} (#2653)"
    )
    assert info.get('release_based') is not True, (
        'post-tag HEAD should use branch check, not release-based check'
    )


# ---------------------------------------------------------------------------
# Regression tests for #2846: _select_apply_compare_ref must mirror the
# check-side decision about whether to advance to the latest tag or to the
# upstream branch. Pre-fix, the check correctly fell through to the branch
# count when HEAD was past the latest tag, but apply still aimed at the tag —
# so clicking "Update Now" no-op'd, restarted the server, and the banner
# re-appeared with the same N commits.
# ---------------------------------------------------------------------------


def test_select_apply_compare_ref_uses_tag_when_head_is_on_tag(tmp_path):
    """HEAD == latest tag → apply path advances to the tag (unchanged)."""
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.16\nv2026.5.10', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v2026.5.16', True
        if args == ['describe', '--tags', '--always']:
            return 'v2026.5.16', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        ref = updates._select_apply_compare_ref(tmp_path)

    assert ref == 'v2026.5.16'


def test_select_apply_compare_ref_falls_through_when_head_is_past_tag(tmp_path):
    """HEAD past latest tag → apply path advances to origin/<branch>, not the tag.

    Mirrors the issue #2846 repro: hermes-agent has tag v2026.5.16, master is
    608 commits ahead, the banner correctly reports 608 commits available
    (post-#2758), but pre-fix apply ran `git pull --ff-only v2026.5.16` — a
    no-op — and the banner reappeared after restart.
    """
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.16', True
        if args == ['describe', '--tags', '--abbrev=0']:
            # HEAD's nearest tag is v2026.5.16; HEAD is 608 commits past it.
            return 'v2026.5.16', True
        if args == ['describe', '--tags', '--always']:
            return 'v2026.5.16-608-g1d22b9c2d', True
        if args == ['rev-parse', '--abbrev-ref', '@{upstream}']:
            return 'origin/main', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        ref = updates._select_apply_compare_ref(tmp_path)

    assert ref == 'origin/main', (
        'apply path must advance to the upstream branch when HEAD is past the '
        'latest tag, otherwise Update Now no-ops and the banner loops (#2846)'
    )


def test_select_apply_compare_ref_no_tags_uses_upstream(tmp_path):
    """No `v*` tags → apply path uses the configured upstream (unchanged)."""
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return '', True
        if args == ['rev-parse', '--abbrev-ref', '@{upstream}']:
            return 'origin/feat/foo', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        ref = updates._select_apply_compare_ref(tmp_path)

    assert ref == 'origin/feat/foo'


def test_select_apply_compare_ref_no_tags_no_upstream_uses_default_branch(tmp_path):
    """No tags and no upstream → fall back to origin/<default-branch>."""
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return '', True
        if args == ['rev-parse', '--abbrev-ref', '@{upstream}']:
            return '', False
        if args == ['symbolic-ref', 'refs/remotes/origin/HEAD']:
            return 'refs/remotes/origin/main', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        ref = updates._select_apply_compare_ref(tmp_path)

    assert ref == 'origin/main'


def test_check_and_apply_paths_agree_when_head_is_past_tag(tmp_path):
    """Check and apply paths must agree: both fall through to origin/<branch>.

    The bug class in #2846 (and #2653 before it) was the two paths drifting
    apart — check said "you're 608 behind origin/main", apply said "advance
    to v2026.5.16". This test pins the symmetry so they can't drift again.
    """
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.16', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v2026.5.16', True
        if args == ['describe', '--tags', '--always']:
            return 'v2026.5.16-608-g1d22b9c2d', True
        if args == ['rev-parse', '--abbrev-ref', '@{upstream}']:
            return 'origin/main', True
        return '', True

    with patch.object(updates, '_run_git', side_effect=fake_git):
        check_result = updates._check_repo_release(tmp_path, 'agent')
        apply_ref = updates._select_apply_compare_ref(tmp_path)

    # Check side falls through (release check returns None → branch check runs)
    assert check_result is None, (
        '_check_repo_release should fall through when HEAD is past the latest '
        'tag (#2653)'
    )
    # Apply side picks the same branch the check would have reported against
    assert apply_ref == 'origin/main', (
        '_select_apply_compare_ref must mirror the check-side fall-through '
        'when HEAD is past the latest tag (#2846)'
    )


def test_check_repo_release_falls_through_when_head_contains_newer_tag(tmp_path):
    """#3140: main-tracking HEAD can already contain the newest release tag.

    The nearest reachable tag is older, so the tag-name gap is positive, but
    applying the latest tag would not fast-forward because HEAD already contains
    it. The release check should fall through to the branch comparison instead
    of advertising a release update.
    """
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.29.2\nv2026.5.29', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v2026.5.29', True
        if args == ['merge-base', '--is-ancestor', 'v2026.5.29.2', 'HEAD']:
            return '', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        result = updates._check_repo_release(tmp_path, 'agent')

    assert result is None, (
        'when HEAD already contains the latest release tag, the release check '
        'must fall through to the branch check instead of reporting a tag gap (#3140)'
    )


def test_select_apply_compare_ref_falls_through_when_head_contains_newer_tag(tmp_path):
    """#3140: apply path mirrors the check-side fall-through for ahead-of-tag HEAD."""
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.29.2\nv2026.5.29', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v2026.5.29', True
        if args == ['merge-base', '--is-ancestor', 'v2026.5.29.2', 'HEAD']:
            return '', True
        if args == ['rev-parse', '--abbrev-ref', '@{upstream}']:
            return 'origin/main', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        ref = updates._select_apply_compare_ref(tmp_path)

    assert ref == 'origin/main', (
        'Update Now must not target a release tag that HEAD already contains; '
        'it should use the branch comparison path instead (#3140)'
    )


def test_select_apply_compare_ref_case_d_older_tag_with_commits_and_newer_tag_exists(tmp_path):
    """Case D — HEAD on older tag + commits + newer tag exists → advance to newer tag.

    Pre-Opus-#2855-fix: the check side correctly reported "behind by N" and
    suggested `latest_tag`, but the apply side's predicate consulted
    `_head_is_past_latest_tag(path, latest_tag)` which returned True (because
    `git describe --tags --always` returns `v.older-N-g...` ≠ `latest_tag`).
    So the apply side fell through to `origin/<branch>` and the pull landed
    PAST the advertised tag — silent drift between check ("advance to
    v2026.5.16") and apply ("pulled to whatever origin/main is now").

    Fix: the apply-side predicate now uses `current_tag` (HEAD's nearest tag)
    AND requires `behind == 0`, exactly mirroring the check-side rule.
    """
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.16\nv2026.5.10', True
        if args == ['describe', '--tags', '--abbrev=0']:
            # HEAD's nearest reachable tag (older one)
            return 'v2026.5.10', True
        if args == ['describe', '--tags', '--always']:
            # HEAD has 3 commits past v2026.5.10, but it does not contain
            # the newer v2026.5.16 release tag.
            return 'v2026.5.10-3-gabcdef12', True
        if args == ['merge-base', '--is-ancestor', 'v2026.5.16', 'HEAD']:
            return '', False
        if args == ['rev-parse', '--abbrev-ref', '@{upstream}']:
            return 'origin/main', True
        return '', True

    with patch.object(updates, '_run_git', side_effect=fake_git):
        apply_ref = updates._select_apply_compare_ref(tmp_path)

    # User is genuinely behind v2026.5.16 (the newer published tag) — apply
    # MUST advance to the tag, NOT fall through to origin/<branch>.
    assert apply_ref == 'v2026.5.16', (
        'case D: HEAD on older tag with commits + newer tag exists. Apply '
        'should advance to the newer tag, not silently fall through to '
        'origin/<branch>. Regression for Opus-flagged drift in #2855.'
    )


def test_check_repo_release_falls_through_when_latest_tag_is_not_ff_reachable(tmp_path):
    """Main-tracking HEAD past an older tag cannot ff to a patch release tag.

    Repro: installer puts agent on main at v2026.5.29+N-g..., maintainers cut
    v2026.5.29.2 from a side branch. Tag gap is positive, but
    ``git pull --ff-only v2026.5.29.2`` fails with diverging branches.
    The release check must fall through to the upstream branch comparison.
    """
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.29.2\nv2026.5.29', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v2026.5.29', True
        if args == ['describe', '--tags', '--always']:
            return 'v2026.5.29-265-g5921d6678', True
        if args == ['merge-base', '--is-ancestor', 'v2026.5.29.2', 'HEAD']:
            return '', False
        if args == ['merge-base', '--is-ancestor', 'HEAD', 'v2026.5.29.2']:
            return '', False
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        result = updates._check_repo_release(tmp_path, 'agent')

    assert result is None


def test_select_apply_compare_ref_falls_through_when_latest_tag_is_not_ff_reachable(tmp_path):
    """Apply path mirrors the ff-unreachable release-tag fall-through."""
    (tmp_path / '.git').mkdir()

    def fake_git(args, cwd, timeout=10):
        if args == ['tag', '--list', 'v*', '--sort=-v:refname']:
            return 'v2026.5.29.2\nv2026.5.29', True
        if args == ['describe', '--tags', '--abbrev=0']:
            return 'v2026.5.29', True
        if args == ['describe', '--tags', '--always']:
            return 'v2026.5.29-265-g5921d6678', True
        if args == ['merge-base', '--is-ancestor', 'v2026.5.29.2', 'HEAD']:
            return '', False
        if args == ['merge-base', '--is-ancestor', 'HEAD', 'v2026.5.29.2']:
            return '', False
        if args == ['rev-parse', '--abbrev-ref', '@{upstream}']:
            return 'origin/main', True
        raise AssertionError(f'unexpected git args: {args!r}')

    with patch.object(updates, '_run_git', side_effect=fake_git):
        ref = updates._select_apply_compare_ref(tmp_path)

    assert ref == 'origin/main'

