A Dart regex that cannot be made to hang

Short summary

Dart's default RegExp uses backtracking, making it vulnerable to ReDoS attacks where a 31-character input can take over 5 seconds. The re2 package provides FFI bindings to Google's RE2 library, which matches in linear time by rejecting backreferences and lookaround at construction time. Re2Set compiles multiple patterns into one automaton for single-pass matching, useful for rule engines and WAFs.

• •Dart's RegExp takes 5.15s on a 31-char ReDoS input; RE2 handles it in 25 microseconds
• •re2 package rejects backreferences/lookaround at construction, guaranteeing linear-time matching
• •Re2Set compiles multiple patterns into one automaton for efficient multi-pattern scanning

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