fix(worktrees): reuse project root for current branch (#77)

src/takopi/worktrees.py

@@ -4,7 +4,13 @@ from pathlib import Path
 
 from .config import ProjectConfig, ProjectsConfig
 from .context import RunContext
-from .utils.git import git_is_worktree, git_ok, git_run, resolve_default_base
+from .utils.git import (
+    git_is_worktree,
+    git_ok,
+    git_run,
+    git_stdout,
+    resolve_default_base,
+)
 
 
 class WorktreeError(RuntimeError):
@@ -23,7 +29,10 @@ def resolve_run_cwd(
         raise WorktreeError(f"unknown project {context.project!r}")
     if context.branch is None:
         return project.path
-    return ensure_worktree(project, context.branch)
+    branch = _sanitize_branch(context.branch)
+    if _matches_project_branch(project.path, branch):
+        return project.path
+    return ensure_worktree(project, branch)
 
 
 def ensure_worktree(project: ProjectConfig, branch: str) -> Path:
@@ -112,6 +121,13 @@ def _sanitize_branch(branch: str) -> str:
     return cleaned
 
 
+def _matches_project_branch(root: Path, branch: str) -> bool:
+    current = git_stdout(["branch", "--show-current"], cwd=root)
+    if not current:
+        return False
+    return current == branch
+
+
 def _ensure_within_root(root: Path, path: Path) -> None:
     root_resolved = root.resolve(strict=False)
     path_resolved = path.resolve(strict=False)

tests/test_worktrees.py

@@ -34,6 +34,29 @@ def test_resolve_run_cwd_rejects_invalid_branch(tmp_path: Path) -> None:
         resolve_run_cwd(ctx, projects=projects)
 
 
+def test_resolve_run_cwd_uses_root_when_branch_matches(
+    monkeypatch, tmp_path: Path
+) -> None:
+    projects = _projects_config(tmp_path)
+
+    def _fake_stdout(args, **_kwargs):
+        if args == ["branch", "--show-current"]:
+            return "main"
+        return None
+
+    def _unexpected(*_args, **_kwargs):
+        raise AssertionError("unexpected")
+
+    monkeypatch.setattr("takopi.worktrees.git_stdout", _fake_stdout)
+    monkeypatch.setattr(
+        "takopi.worktrees.ensure_worktree",
+        _unexpected,
+    )
+
+    ctx = RunContext(project="z80", branch="main")
+    assert resolve_run_cwd(ctx, projects=projects) == tmp_path
+
+
 def test_ensure_worktree_creates_from_base(monkeypatch, tmp_path: Path) -> None:
     project = ProjectConfig(
         alias="z80",