fix: hold the pipeline's fixed outputs for a run

The pipeline locked only --output-dir while it also writes database.json,
install/, README.md and docs/. A run on a scratch output directory could
start beside the run on dist/ and rewrite them. Every run now holds the
repository's .lock first.

scripts/artifacts.py

@@ -217,6 +217,33 @@ def hold_artifact_lock(directory: str) -> Iterator[None]:
             else:
                 os.environ[HELD_LOCK_ENV] = previous
 
+
+# What a pipeline run writes at fixed paths, whatever its --output-dir.
+REPOSITORY_OUTPUTS = ("database.json", "install/", "README.md", "CONTRIBUTING.md", "docs/")
+
+
+@contextlib.contextmanager
+def hold_repository_outputs(root: str = ".") -> Iterator[None]:
+    """Hold the outputs a pipeline writes at fixed paths, for the whole run.
+
+    The output-directory lock let a run on tmp/packtest start beside a run
+    on dist/: both rewrote database.json, and the second to reach the
+    manifest step found install/ held after minutes of work, or, when the
+    steps did not overlap, rewrote the committed manifests from its own
+    state. The lock file is the repository root's .lock.
+    """
+    stack = contextlib.ExitStack()
+    try:
+        stack.enter_context(artifact_lock(root))
+    except ArtifactLockBusy as exc:
+        raise ArtifactLockBusy(
+            f"another pipeline run is writing {', '.join(REPOSITORY_OUTPUTS)} "
+            f"(lock: {os.path.join(root, '.lock')}). Wait for it to finish."
+        ) from exc
+    with stack:
+        yield
+
+
 def _build_timestamp(db: dict | None = None) -> str:
     """Timestamp for generated artifacts.
 

scripts/common.py

@@ -2810,6 +2810,7 @@ from artifacts import (  # noqa: E402,F401
     ArtifactLockBusy,
     artifact_lock,
     hold_artifact_lock,
+    hold_repository_outputs,
     _TIMESTAMP_PATTERNS,
     _strip_timestamps,
 )

scripts/pipeline.py

@@ -68,6 +68,7 @@ from common import (
     artifact_lock,
     github_token,
     hold_artifact_lock,
+    hold_repository_outputs,
     load_data_dir_registry,
 )
 from refresh_data_dirs import hold_data_dirs
@@ -700,13 +701,20 @@ def main() -> None:
     # hold lasts until this process exits: taken step by step, it let another
     # run purge the packs between the build and the integrity check, which
     # then reported every platform SKIP and passed.
+    # database.json, install/, README.md and docs/ sit at fixed paths, so
+    # every run holds them too: a run on a scratch --output-dir otherwise
+    # rewrote them beside the run on dist/.
     held = contextlib.ExitStack()
-    if not args.skip_packs:
-        try:
+    try:
+        held.enter_context(
+            hold_repository_outputs(str(Path(__file__).resolve().parent.parent))
+        )
+        if not args.skip_packs:
             held.enter_context(hold_artifact_lock(args.output_dir))
-        except ArtifactLockBusy as exc:
-            print(f"ERROR: {exc}", file=sys.stderr)
-            sys.exit(1)
+    except ArtifactLockBusy as exc:
+        held.close()
+        print(f"ERROR: {exc}", file=sys.stderr)
+        sys.exit(1)
 
     all_ok = True
     total_start = time.monotonic()