The c2pa.creativeWork action carries fields that c2pa.actions.v2 does not allow

Part of #3596034 (closed).

Problem/Motivation

On upload, c2pa_sign_create_manifest() adds title, creator and description to the c2pa.creativeWork action. The C2PA 2.x action schema has no such fields. c2patool 0.10.2 rejects the whole manifest:

could not decode assertion c2pa.actions.v2 ... unknown field `title`

c2patool 0.20 and later accept it but drop title and creator, so that data is lost without an error.

Steps to reproduce

  1. Install c2patool 0.28.2 and upload an image.
  2. Run c2patool file.jpg. The c2pa.creativeWork action has description only.

Proposed resolution

Move the three fields into the action parameters, which the schema leaves open. The values stay the same.

Definition of done

  • The action has no top-level title, creator or description
  • parameters holds all three, with the same values as before
  • Kernel test checks the three parameters

Testing instructions

  1. Upload an image with c2patool 0.28.2. c2patool file.jpg shows parameters.title (file name), parameters.creator (User ID: #<uid>) and parameters.description.
  2. Repeat with c2patool 0.10.2. Signing succeeds.

AI Compliance

🤖 Generated with the help of an LLM, reviewed and approved by me before posting.