Ref T12335. See that task for discussion. Here are the behavioral changes:
- Statuses can be flagged with locked, which means that tasks in that status are locked to further discussion and interaction.
- A new "CAN_INTERACT" permission facilitates this. For most objects, "CAN_INTERACT" is just the same as "CAN_VIEW".
- For tasks, "CAN_INTERACT" is everyone if the status is a normal status, and no one if the status is a locked status.
- If a user doesn't have "Interact" permission:
- They can not submit the comment form.
- The comment form is replaced with text indicating "This thing is locked.".
- The "Edit" workflow prompts them.
This is a mixture of advisory and hard policy checks but sholuld represent a reasonable starting point.