feat: pull base branch before worktree creation (#4)

* feat: pull base branch before creating new worktree

* chore: update CHANGELOG.md

* chore: fix formatting

Author: ewilazarus

CHANGELOG.md

@@ -9,6 +9,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Changed
 - Increased `prune` unit test coverage
+- Base branch is pulled from origin (best-effort) before creating a new worktree
 
 ### Fixed
 - Removed line breaks from `prune`, `reset`, `root` and `up` commands' help messages

src/git_workspace/git.py

@@ -111,6 +111,20 @@ def fetch_origin(cwd: Path) -> None:
         raise GitFetchError(f"Failed to fetch from origin: {result.stderr.strip()}")
 
 
+def pull_branch(branch: str, cwd: Path) -> None:
+    """
+    Fast-forwards a local branch to match origin without checking it out.
+
+    Best-effort: failures are logged as warnings and silently ignored so that
+    offline or no-remote scenarios don't block worktree creation.
+    """
+    logger.debug("pulling branch %r in %s", branch, cwd)
+    cmd = ["git", "fetch", "origin", f"{branch}:{branch}"]
+    result = subprocess.run(cmd, cwd=cwd, capture_output=True, text=True)
+    if result.returncode != 0:
+        logger.warning("failed to pull branch %r in %s: %s", branch, cwd, result.stderr.strip())
+
+
 def local_branch_exists(branch: str, cwd: Path) -> bool:
     """
     Returns whether a local branch exists

src/git_workspace/worktree.py

@@ -142,6 +142,7 @@ def _create_new(
             branch,
             resolved_base_branch,
         )
+        git.pull_branch(resolved_base_branch, cwd=workspace.dir)
         dir = workspace.paths.worktree(branch)
         git.create_worktree_new(
             dir,

tests/unit/test_git.py

@@ -129,6 +129,24 @@ def test_raises_git_fetch_error_on_failure(self, mock_subprocess_run: MagicMock)
             git.fetch_origin(CWD)
 
 
+class TestPullBranch:
+    def test_builds_correct_command(self, mock_subprocess_run: MagicMock) -> None:
+        git.pull_branch(BASE_BRANCH, CWD)
+
+        assert mock_subprocess_run.call_args.args[0] == [
+            "git",
+            "fetch",
+            "origin",
+            f"{BASE_BRANCH}:{BASE_BRANCH}",
+        ]
+        assert mock_subprocess_run.call_args.kwargs["cwd"] == CWD
+
+    def test_does_not_raise_on_failure(self, mock_subprocess_run: MagicMock) -> None:
+        mock_subprocess_run.return_value.returncode = 1
+
+        git.pull_branch(BASE_BRANCH, CWD)  # should not raise
+
+
 class TestLocalBranchExists:
     def test_builds_correct_command(self, mock_subprocess_run: MagicMock) -> None:
         git.local_branch_exists(BRANCH, CWD)

tests/unit/test_worktree.py

@@ -167,6 +167,35 @@ def test_returns_cwd_result_when_no_branch(
         assert result is worktree
 
 
+class TestCreateNew:
+    @pytest.fixture
+    def mock_git(self, mocker: MockerFixture) -> MagicMock:
+        mocker.patch("git_workspace.worktree.git.pull_branch")
+        mocker.patch("git_workspace.worktree.git.create_worktree_new")
+        return mocker.MagicMock()
+
+    def test_pulls_base_branch_before_creating_worktree(
+        self, mocker: MockerFixture, workspace: MagicMock, mock_git: MagicMock
+    ) -> None:
+        mock_pull = mocker.patch("git_workspace.worktree.git.pull_branch")
+        mocker.patch("git_workspace.worktree.git.create_worktree_new")
+
+        Worktree._create_new(workspace, BRANCH, BASE_BRANCH)
+
+        mock_pull.assert_called_once_with(BASE_BRANCH, cwd=workspace.dir)
+
+    def test_uses_manifest_base_branch_when_none_provided(
+        self, mocker: MockerFixture, workspace: MagicMock, mock_git: MagicMock
+    ) -> None:
+        mock_pull = mocker.patch("git_workspace.worktree.git.pull_branch")
+        mocker.patch("git_workspace.worktree.git.create_worktree_new")
+        workspace.manifest.base_branch = BASE_BRANCH
+
+        Worktree._create_new(workspace, BRANCH, None)
+
+        mock_pull.assert_called_once_with(BASE_BRANCH, cwd=workspace.dir)
+
+
 class TestDelete:
     @pytest.fixture
     def mock_git_remove_worktree(self, mocker: MockerFixture) -> MagicMock: