Govern task context and advance execution pointer

tools/web/check-build-modifier-desktop.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+import hashlib
+import json
+import os
+import pathlib
+import sys
+import tempfile
+
+import bpy
+
+
+def report():
+    obj = bpy.data.objects.get("WebGapBuildObject")
+    if obj is None or obj.type != "MESH":
+        raise RuntimeError("WebGapBuildObject is missing")
+    modifiers = [modifier for modifier in obj.modifiers if modifier.type == "BUILD"]
+    if len(modifiers) != 1:
+        raise RuntimeError(f"expected exactly one BUILD modifier, found {len(modifiers)}")
+    modifier = modifiers[0]
+    return {"meshId": "mesh:" + obj.data.name, "modifier": {"name": modifier.name, "type": modifier.type, "typeCode": bpy.types.Modifier.bl_rna.properties["type"].enum_items[modifier.type].value, "start": round(float(modifier.frame_start), 6), "length": round(float(modifier.frame_duration), 6), "randomize": bool(modifier.use_random_order), "reverse": bool(modifier.use_reverse), "seed": int(modifier.seed), "showViewport": bool(modifier.show_viewport), "showRender": bool(modifier.show_render), "showEditMode": bool(modifier.show_in_editmode), "showOnCage": bool(modifier.show_on_cage)}}
+
+
+def main():
+    arguments = sys.argv[sys.argv.index("--") + 1 :]
+    if len(arguments) != 2:
+        raise SystemExit("usage: blender -b --python check-build-modifier-desktop.py -- FIXTURE REPORT")
+    fixture, output = (pathlib.Path(value).resolve() for value in arguments)
+    bpy.ops.wm.open_mainfile(filepath=str(fixture), load_ui=False)
+    before = report()
+    descriptor, temporary = tempfile.mkstemp(prefix="m16-build-modifier-reopen-", suffix=".blend", dir=fixture.parent)
+    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"build modifier save/reopen drift: {before} != {after}")
+    value = {"schemaVersion": 1, "task": "M16-GAP-00034", "operation": "BUILD_MODIFIER_DESKTOP", "fixture": str(fixture), "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(), "modifier": 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"build-modifier-desktop-ok mesh={after['meshId']} start={after['modifier']['start']} saveReopen=exact")
+
+
+if __name__ == "__main__":
+    main()