Govern task context and advance execution pointer

tools/web/check-grease-pencil-desktop.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+import hashlib
+import json
+import pathlib
+import sys
+import tempfile
+import os
+import bpy
+
+def report():
+    data = bpy.data.grease_pencils.get("GreasePencilData")
+    if data is None: raise RuntimeError("GreasePencilData is missing")
+    layers = []
+    for layer in data.layers:
+        frames = sorted(int(frame.frame_number) for frame in layer.frames)
+        layers.append({"name": layer.name, "frames": frames})
+    return {"name": data.name, "layers": layers}
+
+def main():
+    args = sys.argv[sys.argv.index("--") + 1:]
+    if len(args) != 2: raise SystemExit("usage: blender -b --python check-grease-pencil-desktop.py -- FIXTURE REPORT")
+    fixture, output = (pathlib.Path(value).resolve() for value in args)
+    bpy.ops.wm.open_mainfile(filepath=str(fixture), load_ui=False); before = report(); descriptor, temporary = tempfile.mkstemp(prefix="m16-gp-reopen-", suffix=".blend"); os.close(descriptor)
+    try: bpy.ops.wm.save_as_mainfile(filepath=temporary, check_existing=False, compress=True); bpy.ops.wm.open_mainfile(filepath=temporary, load_ui=False); after = report()
+    finally: pathlib.Path(temporary).unlink(missing_ok=True)
+    if before != after: raise RuntimeError(f"Grease Pencil save/reopen drift: {before} != {after}")
+    value = {"schemaVersion": 1, "task": "M16-GAP-00009", "operation": "GREASE_PENCIL_DATABLOCK_DESKTOP", "fixture": str(fixture), "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(), "greasePencil": after, "saveReopen": "EXACT", "blenderVersion": bpy.app.version_string}; output.parent.mkdir(parents=True, exist_ok=True); output.write_text(json.dumps(value, indent=2, sort_keys=True) + "\n", encoding="utf-8"); print(f"grease-pencil-desktop-ok layers={len(after['layers'])} saveReopen=exact")
+if __name__ == "__main__": main()