Function add_action 

pub async fn add_action(
    pool: &PgPool,
    actor: &Actor,
    change_id: Uuid,
    revision_id: Uuid,
    action: LineAction,
    successor_number: Option<&str>,
) -> AppResult<()>

Adds an action line to a draft change: the released revision is obsoleted (obsolete) or obsoleted and its item declared superseded by successor_number (supersede) when the change is released. Allowed in every group; groups with obsolete_requires_change demand it.

Invariants

• Permission: CAD editor who is the author (or an administrator); the change is a draft (409); the revision is visible (“not found” otherwise) and in a group the actor may edit (403), released (409) and in no other open change (409); every reviewer of the change can see it (409 each). A supersede line needs a visible successor item that is not the item itself (400) and does not close a circle (409); an obsolete line takes no successor (400).
• Locks: the change row (FOR UPDATE), the revision row, the table item_supersessions for a supersede line.
• Audit: change.add_item with the action, only when the line is new or changed.
• Notifications / webhooks: none.
• Atomic: one transaction.