Collection version history¶

(draft)

Background: desired API features (see #13109, #13494)

• Get current + previous versions of a collection with a single API call
• Search all current + previous versions of collections with a single API call
• Stable small numeric "version number" for each version of a given collection

Implementation

• Store all versions in the collection table (much easier to do paging)
• New database column indicates current version's UUID
• New database column indicates user-friendly version number (starting at 1) -- can be assigned safely after locking "current" row for update
• Assign version number to the current version -- this way {uuid,version} can be used as a permanent reference to a specific version
• Flag "include_past_versions" for "list" API to include old versions (otherwise, filter on current_version_uuid=uuid -- might need to adjust indexes to maintain performance)
• Flag in site configuration to enable preserving old versions in database
• Update owner_uuid of all old versions when it changes in the current version
• A permission link to the current version implies permission to its entire history
• Prohibit permission links to old versions (should be handled by check "can only make links to things that are visible to you", and not including old versions)
• Old versions may not be modified except for certain fields which must be synchronized with "current" version changes (owner_uuid, trash_at, delete_at), updating owner_uuid, trash_at, delete_at does not update modified_at (???) so modified_at shows when the version was created
• Old versions with duplicate "name" does not conflict with (owner_uuid, name) uniqueness constraint
• The following changes introduce a new version: manifest_text, description (), properties ()