GET /api/v3/cards?ids= accepts at most 20 ids. Above that the request
fails with 400 "each value in ids must be a mongodb id" — which blames
the ids when the real problem is how many there are. Express/NestJS
parse the query string with qs, whose default arrayLimit is 20; past it
the repeated params stop being an array and become an object keyed "0",
"1", …, and @IsMongoId({ each: true }) then rejects every value.
I had chunked at 40, having read the controller and its DTO and found no
documented ceiling. The limit is not there — it is in the query parser
underneath them, which I did not think to check. Verified live: 20 ids
return 200, 21 return 400 with identical ids.
The worse half of this was mine alone. The crawler caught assembleBoard
failures and dropped them, so every board over 20 cards vanished from
the index while the crawl reported "failures: none". Board errors now go
into Snapshot.failures and are surfaced by refresh_index.
Impact of both fixes on a full re-crawl: 205 files -> 255, and the
reported board (27 cards, 18 files) reads fully. The two failures that
remain are genuine 403s — boards this account cannot see — and are now
visible rather than silent.
Thanks to the bug report, which had the root cause exactly right.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
A full crawl made the instance answer 4 of 26 course pages with an nginx
503 "temporarily unavailable" front-page — it pushes back when several
hundred requests arrive quickly. Nothing retried, so the index was
quietly incomplete: 22 courses and 153 files rather than 26 and 205,
with the failures recorded per course rather than surfaced as a problem.
The client now retries 429/500/502/503/504 and transient network errors
with exponential backoff plus jitter (so parallel crawl workers do not
retry in lockstep), honouring Retry-After when sent. Every call here is
an idempotent GET, so retrying is safe. 401 and 404 are deliberately not
retried: an expired token will not recover, and neither will a bad id.
Re-crawled after the fix: 26 courses, 205 files, zero failures.
Also: `schulcloud --help` printed 'Unknown command "--help"' because a
leading flag was parsed as the command name.
63 tests.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
