Enforce FormParser limits in parser callbacks#3331
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The limit checks ran while draining buffered messages, after `QuerystringParser.write()` had already tokenized the whole chunk. For a body delivered as a single chunk (e.g. via the test client or after `request.body()` cached it), every field was buffered before the limit was reached. Move the count and size checks into the callbacks so parsing stops as soon as a limit is crossed.
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Docs preview: https://e683706e-starlette.marcelotryle.workers.dev |
Kludex
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Follow-up to #3329. The
max_fieldsandmax_part_sizechecks ran while draining buffered messages, afterQuerystringParser.write()had already tokenized the whole chunk. When aapplication/x-www-form-urlencodedbody arrives as a single chunk (e.g. via the test client, or afterrequest.body()has cached it), the parser tokenizes and buffers every field before the drain loop reaches the limit check.This moves the count and size checks into the
on_field_*callbacks, which run duringwrite(), so parsing stops as soon as a limit is crossed regardless of how the body is chunked. Behaviour and error messages are unchanged; only the point at which parsing aborts moves earlier.AI Disclaimer
This PR was developed with the assistance of either Claude or Codex. I've reviewed and verified the changes.