0008: Migrations are only added, and run on start
Context
Section titled “Context”Self-hosters skip versions. An upgrade that needs a manual step per version is an upgrade that doesn’t happen.
Decision
Section titled “Decision”The server applies every migration it has that the database doesn’t, in order, in one transaction, under an advisory lock, before serving. Released migrations are never edited. CI fails a pull request that edits one, that changes the schema without one, or whose migrations don’t take the base branch’s database, filled with rows, to the new schema.
Consequences
Section titled “Consequences”- Any release upgrades from any earlier one by starting it.
- Destructive schema changes take two releases: stop using, then drop.
- The filled database CI upgrades (a fixture of rows in use) has to be kept in step with the schema.