chore(repo): replace app symlink/submodule with in-repo app directory; enable committing app/Dockerfile and tooling\n\nCo-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

app/migration_pipeline/git_manager.py

@@ -0,0 +1,135 @@
+"""Git worktree + branch management for batch isolation.
+
+Each batch × track combination gets its own git worktree so that:
+  - Track A and Track B never share filesystem state.
+  - Build directories are fully independent.
+  - Every successful file migration is committed immediately to its branch.
+"""
+
+from __future__ import annotations
+
+import subprocess
+from pathlib import Path
+
+
+# ---------------------------------------------------------------------------
+# Low-level helper
+# ---------------------------------------------------------------------------
+
+def _git(args: list[str], cwd: Path | None = None) -> tuple[int, str, str]:
+    result = subprocess.run(
+        ["git"] + args,
+        capture_output=True,
+        text=True,
+        cwd=str(cwd) if cwd else None,
+    )
+    return result.returncode, result.stdout.strip(), result.stderr.strip()
+
+
+# ---------------------------------------------------------------------------
+# Branch / worktree lifecycle
+# ---------------------------------------------------------------------------
+
+def branch_name(batch_id: str, track_id: str) -> str:
+    """Canonical branch name: ``migration/<batch_id>/<track_id>``."""
+    return f"migration/{batch_id}/{track_id}"
+
+
+def setup_worktree(
+    batch_id: str,
+    track_id: str,
+    repo_root: Path,
+    workspace_root: Path,
+) -> Path:
+    """Ensure a git worktree exists for *batch_id* × *track_id*.
+
+    Creates the branch (from HEAD) if it does not yet exist.
+    Returns the worktree path.
+    """
+    branch = branch_name(batch_id, track_id)
+    worktree_path = workspace_root / batch_id / track_id
+
+    # Create the branch if needed.
+    rc, _, _ = _git(["rev-parse", "--verify", branch], cwd=repo_root)
+    if rc != 0:
+        _git(["branch", branch], cwd=repo_root)
+
+    # Remove stale worktree entry (if the directory was deleted manually).
+    _git(["worktree", "prune"], cwd=repo_root)
+
+    # Check whether the worktree is already registered.
+    _, wt_list, _ = _git(["worktree", "list", "--porcelain"], cwd=repo_root)
+    if str(worktree_path) in wt_list:
+        return worktree_path
+
+    worktree_path.parent.mkdir(parents=True, exist_ok=True)
+    rc, out, err = _git(
+        ["worktree", "add", str(worktree_path), branch],
+        cwd=repo_root,
+    )
+    if rc != 0:
+        raise RuntimeError(
+            f"git worktree add failed for {worktree_path}: {err}"
+        )
+    return worktree_path
+
+
+def teardown_worktree(
+    batch_id: str,
+    track_id: str,
+    repo_root: Path,
+    workspace_root: Path,
+) -> None:
+    """Remove the worktree (but keep the branch)."""
+    worktree_path = workspace_root / batch_id / track_id
+    _git(["worktree", "remove", "--force", str(worktree_path)], cwd=repo_root)
+    _git(["worktree", "prune"], cwd=repo_root)
+
+
+# ---------------------------------------------------------------------------
+# Per-file commit helpers
+# ---------------------------------------------------------------------------
+
+def commit_migrated_file(
+    file_path_in_worktree: Path,
+    worktree_path: Path,
+    track_id: str,
+) -> None:
+    """Stage and commit a single successfully migrated file."""
+    _git(["add", str(file_path_in_worktree)], cwd=worktree_path)
+    rel = file_path_in_worktree.relative_to(worktree_path)
+    _git(
+        ["commit", "-m", f"migrate({track_id}): {rel}"],
+        cwd=worktree_path,
+    )
+
+
+def commit_generated_tests(
+    tests_dir: Path,
+    worktree_path: Path,
+    track_id: str,
+    test_prefix: str,
+) -> None:
+    """Stage and commit generated test files and their CMakeLists entry."""
+    _git(["add", str(tests_dir)], cwd=worktree_path)
+    _git(
+        ["commit", "-m", f"test({track_id}): generated tests for {test_prefix}"],
+        cwd=worktree_path,
+    )
+
+
+def commit_batch_summary(
+    worktree_path: Path,
+    track_id: str,
+    batch_id: str,
+) -> None:
+    """Final commit for a batch (quarantine files, reports, etc.)."""
+    _git(["add", "-A"], cwd=worktree_path)
+    rc, _, _ = _git(
+        ["diff", "--cached", "--quiet"], cwd=worktree_path
+    )
+    if rc != 0:   # there are staged changes
+        _git(
+            ["commit", "-m", f"batch({track_id}): finalise {batch_id}"],
+            cwd=worktree_path,
+        )