feat: Use original commit message on one commit updates

src/voraus_template_updater/_update_projects.py

@@ -180,14 +180,19 @@ def _update_project(
 
     cruft.update(Path(local_repo.working_dir), checkout=project.template_branch)
 
+    template_commit_messages = _get_template_commit_messages(project, github_access_token)
     local_repo.git.add(all=True)
-    local_repo.index.commit(PR_TITLE)
+    if len(template_commit_messages) == 1:
+        local_repo.index.commit(template_commit_messages[0])
+    else:
+        local_repo.index.commit(PR_TITLE)
     local_repo.git.push("--set-upstream", "origin", branch)
 
-    pr_body = _get_pr_body(project, github_access_token)
+    pr_title = _get_pr_title(template_commit_messages)
+    pr_body = _get_pr_body(project, template_commit_messages)
 
     pull_request = remote_repo.create_pull(
-        base=remote_repo.default_branch, head=branch.name, title=PR_TITLE, body=pr_body
+        base=remote_repo.default_branch, head=branch.name, title=pr_title, body=pr_body
     )
 
     _logger.info(
@@ -198,7 +203,7 @@ def _update_project(
     return pull_request
 
 
-def _get_pr_body(project: Project, github_access_token: str) -> str:
+def _get_template_commit_messages(project: Project, github_access_token: str) -> List[str]:
     with TemporaryDirectory() as tmp_path:
         template_repo = _clone_repo(project.template_url, github_access_token, Path(tmp_path))
 
@@ -222,12 +227,33 @@ def _get_pr_body(project: Project, github_access_token: str) -> str:
             r"\(#(\d+)\)", lambda match: f"([PR]({link.format(match.groups()[0])}))", message
         )
 
+    return commit_messages
+
+
+def _get_pr_title(template_commit_messages: List[str]) -> str:
+    if len(template_commit_messages) == 1:
+        message = template_commit_messages[0]
+        return message.strip().splitlines()[0]
+
+    return PR_TITLE
+
+
+def _get_pr_body(project: Project, template_commit_messages: List[str]) -> str:
+    if len(template_commit_messages) == 1:
+        message = template_commit_messages[0]
+        lines = message.strip().splitlines()
+        if len(lines) > 1:
+            return "".join(message.strip().splitlines()[1:])
+        return ""
+
     # Indent all lines after the first line of a commit message by two spaces
     # This leads to nicer bullet points in the pull request body
-    commit_messages = ["\n  ".join(commit_message.strip().splitlines()) for commit_message in commit_messages]
+    template_commit_messages = [
+        "\n  ".join(commit_message.strip().splitlines()) for commit_message in template_commit_messages
+    ]
 
     # Construct a pull request message containing the PR header and a bullet point list of changes and their explanation
-    return PR_BODY_HEADER.format(project.template_branch) + "- " + "\n\n- ".join(commit_messages) + "\n"
+    return PR_BODY_HEADER.format(project.template_branch) + "- " + "\n\n- ".join(template_commit_messages) + "\n"
 
 
 if __name__ == "__main__":  # pragma: no cover

tests/unit/test_update_projects.py

@@ -18,6 +18,8 @@
     _check_and_update_projects,
     _clone_repo,
     _get_cruft_config,
+    _get_pr_body,
+    _get_pr_title,
 )
 
 ORGANIZATION = "dummy-organization"
@@ -318,11 +320,13 @@ def test_up_to_date_project(
     assert summary.projects[0].status == Status.UP_TO_DATE
 
 
+@pytest.mark.parametrize("is_incremental_update", [True, False], ids=["Incremental Update", "Bulk Update"])
 @patch("voraus_template_updater._update_projects.cruft.update")
 @patch("voraus_template_updater._update_projects.cruft.check")
 def test_update_project_success(
     cruft_check_mock: MagicMock,
     cruft_update_mock: MagicMock,
+    is_incremental_update: bool,
     repo_mock: MagicMock,
     cloned_repo_mocks: List[MagicMock],
     cruft_config: CruftConfig,
@@ -343,7 +347,8 @@ def _create_commit_mock(i: int) -> MagicMock:
         return commit_mock
 
     cloned_template_repo.git.rev_parse.return_value = "newest_commit"
-    cloned_template_repo.iter_commits.return_value = [_create_commit_mock(i) for i in range(2)]
+    number_new_commits = 1 if is_incremental_update else 2
+    cloned_template_repo.iter_commits.return_value = [_create_commit_mock(i) for i in range(number_new_commits)]
 
     with caplog.at_level(logging.INFO):
         summary = _check_and_update_projects(ORGANIZATION)
@@ -359,18 +364,31 @@ def _create_commit_mock(i: int) -> MagicMock:
     cloned_template_repo.iter_commits.assert_called_once_with(f"{cruft_config.commit}..newest_commit")
 
     cloned_project_repo.git.add.assert_called_with(all=True)
-    cloned_project_repo.index.commit.assert_called_with(PR_TITLE)
+    if is_incremental_update:
+        cloned_project_repo.index.commit.assert_called_with(
+            "Commit title ([PR](some-template-url/pull/0))\n\nDescription 0\n"
+        )
+    else:
+        cloned_project_repo.index.commit.assert_called_with(PR_TITLE)
     cloned_project_repo.git.push.assert_called_with("--set-upstream", "origin", branch_mock)
 
-    expected_pr_body = (
-        "Contains the following changes to get up-to-date with the newest version of the template's 'dev' branch."
-        "\n\n"
-        "- Commit title ([PR](some-template-url/pull/0))\n  \n  Description 0\n\n"
-        "- Commit title ([PR](some-template-url/pull/1))\n  \n  Description 1\n"
-    )
+    if is_incremental_update:
+        expected_pr_body = "Description 0"
+    else:
+        expected_pr_body = (
+            "Contains the following changes to get up-to-date with the newest version of the template's 'dev' branch."
+            "\n\n"
+            "- Commit title ([PR](some-template-url/pull/0))\n  \n  Description 0\n\n"
+            "- Commit title ([PR](some-template-url/pull/1))\n  \n  Description 1\n"
+        )
+
+    if is_incremental_update:
+        expected_pr_title = "Commit title ([PR](some-template-url/pull/0))"
+    else:
+        expected_pr_title = PR_TITLE
 
     repo_mock.create_pull.assert_called_once_with(
-        base=repo_mock.default_branch, head=branch_mock.name, title=PR_TITLE, body=expected_pr_body
+        base=repo_mock.default_branch, head=branch_mock.name, title=expected_pr_title, body=expected_pr_body
     )
 
     assert caplog.record_tuples[1] == (
@@ -384,3 +402,43 @@ def _create_commit_mock(i: int) -> MagicMock:
     assert summary.projects[0].status == Status.UPDATED_THIS_RUN
     assert summary.projects[0].pull_request is not None
     assert summary.projects[0].pull_request.html_url == "https://some-pr.com"
+
+
+@pytest.mark.parametrize(
+    argnames=["commit_messages", "expected_title"],
+    argvalues=[
+        ([], PR_TITLE),
+        (["Lorem ipsum"], "Lorem ipsum"),
+        (["Lorem ipsum\n\ndolor sit amet\n"], "Lorem ipsum"),
+        (["Lorem ipsum\ndolor sit amet\n"], "Lorem ipsum"),
+        (["Lorem ipsum\n\ndolor sit amet\n", "Commit title\n Commit body.\n"], PR_TITLE),
+    ],
+)
+def test_get_pr_title(commit_messages: List[str], expected_title: str) -> None:
+    assert _get_pr_title(commit_messages) == expected_title
+
+
+@pytest.mark.parametrize(
+    argnames=["commit_messages", "expected_body"],
+    argvalues=[
+        (
+            [],
+            "Contains the following changes to get up-to-date with the newest version of the template's 'dev' branch."
+            "\n\n- \n",
+        ),  # Empty commit should never happen. But this test shows, that we do not crash.
+        (["Lorem ipsum"], ""),
+        (["Lorem ipsum\n\ndolor sit amet"], "dolor sit amet"),
+        (["Lorem ipsum\ndolor sit amet\n"], "dolor sit amet"),
+        (
+            ["Lorem ipsum", "Commit title\n\nCommit body.\n"],
+            "Contains the following changes to get up-to-date with the newest version of the template's 'dev' branch."
+            "\n\n"
+            "- Lorem ipsum\n\n"
+            "- Commit title\n  \n  Commit body.\n",
+        ),
+    ],
+)
+def test_get_pr_body(commit_messages: List[str], expected_body: str) -> None:
+    project = MagicMock()
+    project.template_branch = "dev"
+    assert _get_pr_body(project, commit_messages) == expected_body