Fix bug with multiline regexp and right anchor #13200
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byroot
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Apr 29, 2025
https://bugs.ruby-lang.org/issues/21291 This seems to be an optimization bug. With `ONIG_DONT_OPTIMIZE` defined, `"aa\n" =~ /$.*/m` returns 2 as the author expected. But with optimizations turned on it does not find a match. The optimization involves setting `ANCHOR_ANYCHAR_STAR_ML`, which ultimately limits the regexp search to the starting position. But in this case, because of the right anchor, we won't find a match at the starting position. We need to keep searching, and that is what happens when the optimization is disable. This commit adds the anchor information to the env, so we can skip the optimization when we've seen a right anchor prior to the quantifier.
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https://bugs.ruby-lang.org/issues/21291
This seems to be an optimization bug. With
ONIG_DONT_OPTIMIZEdefined,"aa\n" =~ /$.*/mreturns 2 as the bug report author expected. But with optimizations turned on it does not find a match.The optimization involves setting
ANCHOR_ANYCHAR_STAR_ML, which ultimately limits the regexp search to the starting position. But in this case, because of the right anchor, we won't find a match at the starting position. We need to keep searching, and that is what happens when the optimization is disabled.This commit adds the anchor information to the env, so we can skip the optimization when we've seen a right anchor prior to the quantifier.