goldset

Whole file

lark-parser/lark

The author described this change as “Fix lexer_callbacks silently dropped for keyword terminals”. It counts as a record because the check below fails on the code as it stood at c169b26a5 and passes on 46bbc82b3, with nothing else changed between the two runs.

Projectlark-parser/lark
Fix saved2026-07-08
Sharing licenceMIT · LICENSE
Change size+7 −2

What the code was meant to do, written into the code itself as a save note

Fix lexer_callbacks silently dropped for keyword terminals

The change

595595
596596 for type_, f in self.user_callbacks.items():
597597 if type_ in self.callback:
598- # Already a callback there, probably UnlessCallback
599- self.callback[type_] = CallChain(self.callback[type_], f, lambda t: t.type == type_)
598+ # Already a callback there, probably UnlessCallback.
599+ # Bind ``type_`` per iteration; otherwise every CallChain's
600+ # condition closes over the loop variable and checks the last
601+ # terminal's name, silently skipping the other callbacks.
602+ self.callback[type_] = CallChain(
603+ self.callback[type_], f, lambda t, type_=type_: t.type == type_
604+ )
600605 else:
601606 self.callback[type_] = f
602607

The check that tells the two apart

fail→pass·tests/test_grammar.py::TestGrammar::test_lexer_callbacks_with_keyword_terminals

Check file tests/test_grammar.py, taken without changes from the fix and copied onto the older code, so the exact same check runs against both versions.

Origin and history

The fix46bbc82b3a5218e3a7593bd94f62a815c97be6e1
The code before itc169b26a5bec9d47e590bf4be83691bcbdfe7b6b
Broken version dated2026-06-04
Modulelark.lexer
Units changedBasicLexer
Fingerprint7399096dd2eb277d
Checked2026-08-18 by goldset/0.1

Every field above is generated by our program. None of it is written by hand.

Other bugs found in lark-parser/lark