buildstream/_gitsourcebase.py: Fix case where HEAD is tagged

`git rev-list --boundary HEAD..HEAD` does not return any boundary.
So in this case we need to manually tag the HEAD as a boundary.

buildstream/_gitsourcebase.py

@@ -296,19 +296,24 @@ class GitMirror(SourceFetcher):
             shallow = set()
             for _, commit_ref, _ in self.tags:
 
-                _, out = self.source.check_output([self.source.host_git, 'rev-list',
-                                                   '--ancestry-path', '--boundary',
-                                                   '{}..{}'.format(commit_ref, self.ref)],
-                                                  fail="Failed to get git history {}..{} in directory: {}"
-                                                  .format(commit_ref, self.ref, fullpath),
-                                                  fail_temporarily=True,
-                                                  cwd=self.mirror)
-                for line in out.splitlines():
-                    rev = line.lstrip('-')
-                    if line[0] == '-':
-                        shallow.add(rev)
-                    else:
-                        included.add(rev)
+                if commit_ref == self.ref:
+                    # rev-list does not work in case of same rev
+                    shallow.add(self.ref)
+                else:
+                    _, out = self.source.check_output([self.source.host_git, 'rev-list',
+                                                       '--ancestry-path', '--boundary',
+                                                       '{}..{}'.format(commit_ref, self.ref)],
+                                                      fail="Failed to get git history {}..{} in directory: {}"
+                                                      .format(commit_ref, self.ref, fullpath),
+                                                      fail_temporarily=True,
+                                                      cwd=self.mirror)
+                    self.source.warn("refs {}..{}: {}".format(commit_ref, self.ref, out.splitlines()))
+                    for line in out.splitlines():
+                        rev = line.lstrip('-')
+                        if line[0] == '-':
+                            shallow.add(rev)
+                        else:
+                            included.add(rev)
 
             shallow -= included
             included |= shallow

tests/sources/git.py

@@ -883,6 +883,117 @@ def test_git_describe(cli, tmpdir, datafiles, ref_storage, tag_type):
     assert p.returncode != 0
 
 
+@pytest.mark.skipif(HAVE_GIT is False, reason="git is not available")
+@pytest.mark.datafiles(os.path.join(DATA_DIR, 'template'))
+@pytest.mark.parametrize("ref_storage", [('inline'), ('project.refs')])
+@pytest.mark.parametrize("tag_type", [('annotated'), ('lightweight')])
+def test_git_describe_head_is_tagged(cli, tmpdir, datafiles, ref_storage, tag_type):
+    project = str(datafiles)
+
+    project_config = _yaml.load(os.path.join(project, 'project.conf'))
+    project_config['ref-storage'] = ref_storage
+    _yaml.dump(_yaml.node_sanitize(project_config), os.path.join(project, 'project.conf'))
+
+    repofiles = os.path.join(str(tmpdir), 'repofiles')
+    os.makedirs(repofiles, exist_ok=True)
+    file0 = os.path.join(repofiles, 'file0')
+    with open(file0, 'w') as f:
+        f.write('test\n')
+
+    repo = create_repo('git', str(tmpdir))
+
+    def tag(name):
+        if tag_type == 'annotated':
+            repo.add_annotated_tag(name, name)
+        else:
+            repo.add_tag(name)
+
+    ref = repo.create(repofiles)
+    tag('uselesstag')
+
+    file1 = os.path.join(str(tmpdir), 'file1')
+    with open(file1, 'w') as f:
+        f.write('test\n')
+    repo.add_file(file1)
+
+    file2 = os.path.join(str(tmpdir), 'file2')
+    with open(file2, 'w') as f:
+        f.write('test\n')
+    repo.branch('branch2')
+    repo.add_file(file2)
+
+    repo.checkout('master')
+    file3 = os.path.join(str(tmpdir), 'file3')
+    with open(file3, 'w') as f:
+        f.write('test\n')
+    repo.add_file(file3)
+
+    tagged_ref = repo.merge('branch2')
+    tag('tag')
+
+    config = repo.source_config()
+    config['track'] = repo.latest_commit()
+    config['track-tags'] = True
+
+    # Write out our test target
+    element = {
+        'kind': 'import',
+        'sources': [
+            config
+        ],
+    }
+    element_path = os.path.join(project, 'target.bst')
+    _yaml.dump(element, element_path)
+
+    if ref_storage == 'inline':
+        result = cli.run(project=project, args=['source', 'track', 'target.bst'])
+        result.assert_success()
+    else:
+        result = cli.run(project=project, args=['source', 'track', 'target.bst', '--deps', 'all'])
+        result.assert_success()
+
+    if ref_storage == 'inline':
+        element = _yaml.load(element_path)
+        tags = _yaml.node_sanitize(element['sources'][0]['tags'])
+        assert len(tags) == 1
+        for tag in tags:
+            assert 'tag' in tag
+            assert 'commit' in tag
+            assert 'annotated' in tag
+            assert tag['annotated'] == (tag_type == 'annotated')
+
+        assert set([(tag['tag'], tag['commit']) for tag in tags]) == set([('tag', repo.rev_parse('tag^{commit}'))])
+
+    checkout = os.path.join(str(tmpdir), 'checkout')
+
+    result = cli.run(project=project, args=['build', 'target.bst'])
+    result.assert_success()
+    result = cli.run(project=project, args=['checkout', 'target.bst', checkout])
+    result.assert_success()
+
+    if tag_type == 'annotated':
+        options = []
+    else:
+        options = ['--tags']
+    describe = subprocess.check_output(['git', 'describe'] + options,
+                                       cwd=checkout).decode('ascii')
+    assert describe.startswith('tag')
+
+    tags = subprocess.check_output(['git', 'tag'],
+                                   cwd=checkout).decode('ascii')
+    tags = set(tags.splitlines())
+    assert tags == set(['tag'])
+
+    rev_list = subprocess.check_output(['git', 'rev-list', '--all'],
+                                       cwd=checkout).decode('ascii')
+
+    assert set(rev_list.splitlines()) == set([tagged_ref])
+
+    p = subprocess.run(['git', 'log', repo.rev_parse('uselesstag')],
+                       cwd=checkout)
+    assert p.returncode != 0
+
+
 @pytest.mark.skipif(HAVE_GIT is False, reason="git is not available")
 @pytest.mark.datafiles(os.path.join(DATA_DIR, 'template'))
 def test_git_describe_relevant_history(cli, tmpdir, datafiles):