Fix catastrophic backtracking in not_alphanum_paragraph_v1 regex#284
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Chessing234 wants to merge 1 commit intoallenai:mainfrom
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Fix catastrophic backtracking in not_alphanum_paragraph_v1 regex#284Chessing234 wants to merge 1 commit intoallenai:mainfrom
Chessing234 wants to merge 1 commit intoallenai:mainfrom
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Remove nested quantifier `[...]+` inside `(...)+` that causes exponential backtracking on long emoji sequences. The outer `)+` already handles repetition. Fixes allenai#123
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Bug
The
not_alphanum_paragraph_v1tagger's regex contains a nested quantifier pattern[emoji-ranges]+inside(...)+, creating a classic(X+)+catastrophic backtracking scenario. As reported in #123, ~44 emoji characters cause 64 seconds of processing, and ~68 emoji characters cause the tagger to hang indefinitely.Root cause
Line 21 of
python/dolma/taggers/punctuation.py: the inner+on the emoji character class is redundant because the outer group)+already handles matching multiple characters. Together they form a nested quantifier that causes the regex engine to explore exponentially many partitions.Fix
Remove the inner
+(1-character deletion). The outer)+still matches one-or-more of any character in the alternation (punctuation, whitespace, or emoji), preserving the regex's matching semantics while eliminating exponential backtracking.Closes #123