[release/10.0] Fix balancing groups incorrectly removed from negative lookarounds #120888
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Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>
Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>
stephentoub
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MihaZupan
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artl93
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merging: Helix and OSX, per Toub. |
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Backport of #120856 to release/10.0
/cc @stephentoub @copilot
Customer Impact
Balancing groups inside of negative lookarounds get removed erroneously, erroneously changing the behavior of those (rare but possible) regexes.
Regression
Last .NET 10 preview.
Testing
Additional unit tests added.
Risk
Low. The fix is adding an extra condition to the if guarding an optimization; it simply makes the optimization apply less often.