moonbitlang / core / 3138

96%

push

github

perf(string): delay StringBuilder allocation in Regex::replace_by

replace_by was always creating a StringBuilder and materializing a
new string, even when the regex didn't match anything. For large
input strings with no matches, this turned a cheap check into an
O(n) copy.

Fix: delay buffer creation until the first match is found. When
there are no matches, return the original string view directly
without any allocation.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

12 of 12 new or added lines in 1 file covered. (100.0%)

13825 of 14440 relevant lines covered (95.74%)

176034.47 hits per line