dmesg came back empty, and the evidence that actually settles it was in the original log the whole time. Step 7 `Run migrations` succeeded, then step 9's globalSetup applied all six migrations again from scratch. Both point at the same database — migrate.js reads PGHOST/PGDATABASE and the job sets those and TEST_PG* to the same service and the same redefined_test — so had step 7 migrated it, globalSetup would have printed "No migrations to run!", which is what a local run prints.
It found an empty database. The wipe was already happening before the tests started, which makes this a database being reset repeatedly rather than a container dying partway through a heavy run, and accounts cleanly for the empty dmesg: a restart is not a kill.
The suspect moves from memory pressure to the runner's handling of `services:`, where act_runner has been uneven across releases. The diagnostics change with it: A3 is dropped because it was designed to catch starvation, A2 is demoted to a fallback, and the new first check needs nothing but the Gitea UI — compare step 7 and step 9's migration output in any failing run.
The superseded hypothesis is kept rather than deleted. A future reader finding memory ruled out is better served by seeing why it was suspected and what refuted it than by a document that never mentions it.
Refs #154
The diagnosis so far, what has been ruled out, and the three read-only checks that would confirm or refute it — with slots to paste the output into and a note against each saying what the answer means.
Written as a working document rather than a summary because the decisive check has a timing constraint that is easy to miss: the Postgres service container is deleted when the job finishes, so watching it has to happen during the run. Discovering that after the fact costs another full run.
It also records the negative result deliberately. If the container is healthy throughout, the hypothesis is wrong and the document says which suspect is next, rather than leaving an abandoned theory for the next reader to re-derive.
Refs #154
bermudalamb