The migration rows answer "did this run". They cannot answer "is this
application installed", and the difference is not academic: an install that
stopped partway leaves every migration reading applied and a row saying the
install never finished. Until now nothing printed that row.
[order] 1.0.0 failed at order-1793800000000
applied order-1793800000000 2026-09-10 21:02:07
The application list is the union of the two sources rather than either one.
Reading it from sys_app alone would drop an application whose migrations ran
under plain `migrate`, which records no row; reading it from the migration
rows alone drops one whose code has been taken out of the binary, which is
when somebody most wants to see it named - that one now gets a group of its
own, empty, saying why.
A database from before sys_app existed prints exactly what it printed before.
`migrate status` has to keep working on a database that has not been migrated
at all, which is when it is most wanted.
Four degradations turn the new assertions red: dropping the sys_app-only
applications from the listing, printing no summary, not narrowing sys_app by
--app, and reporting an unfinished install as an installed one.
--app rejects a code nothing was registered under, on all three paths. It used
to take a typo as "nothing matched" and report success: migrate said the app
was unknown and still exited 0, while --dry-run and status printed the same
words an up-to-date database produces.
zhangwenjian