Bump fancy-regex from 0.13.0 to 0.19.2 in /engine

[dependabot]

Bumps fancy-regex from 0.13.0 to 0.19.2.

Release notes

Sourced from fancy-regex's releases.

0.19.2

Added

• Add a leftmost_longest feature (off by default) that adds a method to the RegexBuilder/RegexOptionsBuilder for building a VM which would operate in leftmost-longest match mode instead of the regular leftmost-first mode. Useful for POSIX compliance. (#281)

Changed

Fixed

0.19.1

Added

• Add a perf-dfa-full feature (off by default, mirroring the regex crate) that lets regex-automata eagerly build fully compiled dense DFAs for small patterns, for workloads that compile few regexes and match them very heavily (#272)

Changed

• Add VM instruction for case insensitive literals when in Unicode mode, to keep the build cost bounded (#268) and ensured the toy example graph output remains readable instead of being super verbose (#269)
• Compilation performance: the regex-automata dependency no longer enables the dfa-build feature by default. With dfa-build enabled, meta::Regex eagerly determinizes a full dense DFA for every small pattern, which dominated build time of simple class-containing patterns (e.g. \b(extern)\s+(crate) compiled ~4x slower than with the regex crate, which also ships without dfa-build); searches use the lazy DFA instead, with no measurable match-time difference (#272)
• Compilation performance: identical delegated fragments within one compile now share a single regex-automata engine instead of each building their own. Alternation-heavy patterns (TextMate grammar lookbehinds especially) often repeat the same fragment many times; on such patterns this removes a large share of build time (#277)

Fixed

• The playground didn't show when a literal or backreference was being matched case insensitively in the analysis tree view (#269)
• Seek patterns could become very large when recursive backrefs and subroutine calls were inlined, without bringing much benefit (#270)
• The optimize_nested_repeats pass could rewrite an optional capture group like (\w+)? into (\w*), causing an unmatched optional group to be reported as an empty match (Some("")) instead of None (#276)

0.19.0

Added

• Add BytesMode and the RegexInput trait so the matching and capture APIs can operate on strings or bytes, and allows to opt out of unicode handling if desired (#248)
  • Also allows searching within a range without slicing (#253)
  • Assertions can be overridden at runtime, if the regex builder allow_input_assertion_overrides option was used (#254)
  • Search can be performed in anchored mode, searching only at the start position specified (#263)
• Add experimental seek optimization to only invoke the VM at candidate positions where a match could occur (#246)
• Add RegexBuilder::disallow_empty_match_at_eof_after_newline to reject empty matches at the end of the haystack following a trailing newline, to match Oniguruma behavior (#247)
• Add RegexSet API for efficiently matching multiple patterns against the same text (#255)

Changed

• Case-insensitive backreference comparison of non-ASCII text now uses direct Unicode simple case folding instead of building a regex engine per comparison, which makes patterns like (?i)(\w+)\1 orders of magnitude faster on non-ASCII haystacks. The comparison is now strict fold equality over the captured text's byte-length window: a case-folded prefix of the window no longer counts as a match (previously a substring search could accept one and misalign the match end)
• Compilation performance: delegated regex-automata engines (including the whole pattern in the easy case) are now built from a directly-constructed Hir instead of a re-serialized pattern string, and RegexSet parses each pattern once for both of its set-wide engines instead of three times. This reduces compile time and peak compile memory, especially for RegexSet and small easy patterns
• Match performance: the backtracking VM's working memory (saves, backtrack stack, delegate slots) is pooled and reused across runs, making is_match/find/find_iter and RegexSet candidate verification allocation-free per call; RegexSet::find_input no longer allocates at failed candidate positions. Short and repeated matches improve substantially (up to ~30% for small patterns, ~10% for find_iter over many matches); single very long backtracking runs, where per-run setup is fully amortized anyway, can be a few percent slower
• Matches, CaptureMatches, Captures, and SubCaptureMatches are now generic over RegexInput, which is a breaking change for code that named these types explicitly (#248)
• Patterns no longer force Unicode mode during parsing, and inline (?u) / (?-u) flags are accepted when they agree with the builder configuration

Fixed

• Fix bug whereby inline flags were not overriding the builder options (#247)
• Fix bug whereby \G optimizations were applying where they shouldn't, giving wrong results (#256)
• Support Oniguruma quantifier parsing rules, whereby swapped ordering causes possessiveness, + only causes possessiveness after ?, * or + (#258)

Upgrade guide

If you previously stored i.e. Captures, you would need to change the type to Captures<str> to get the code to compile.

0.18.0

Added

• Add support for \N to mean any character except newline, for Oniguruma compatibility (#206)
• Add support for (*FAIL) backtracking control verb (#210)
• Add support for more \p{...} and \P{...} aliases, for Oniguruma compatibility (#207)
• Add support for word boundaries and zero-length fancy patterns inside variable lookbehinds (at top level) (#216)
• Add support for \R to mean general newline, matching all common line break characters, treating \r\n atomically (#220)
• Add support for the regex crate's (?R) CRLF mode flag (#238)
• Add support for subroutine calls (including recursion up to 20 levels deep, matching Oniguruma behavior) \g<1> (#230)
• Add support for Oniguruma's absent repeater (?~abc) (#233)

... (truncated)

Changelog

Sourced from fancy-regex's changelog.

[0.19.2] - 2026-09-13

Added

• Add a leftmost_longest feature (off by default) that adds a method to the RegexBuilder/RegexOptionsBuilder for building a VM which would operate in leftmost-longest match mode instead of the regular leftmost-first mode. Useful for POSIX compliance. (#281)

Changed

Fixed

• Fix a panic in capture_names() for a pattern with a zero-repeated named group such as (?<n>a){0} (#275)
• Literal bytes were being encoded as utf-8 in Ascii mode, now they match the exact byte literal

[0.19.1] - 2026-09-06

Added

• Add a perf-dfa-full feature (off by default, mirroring the regex crate) that lets regex-automata eagerly build fully compiled dense DFAs for small patterns, for workloads that compile few regexes and match them very heavily (#272)

Changed

• Add VM instruction for case insensitive literals when in Unicode mode, to keep the build cost bounded (#268) and ensured the toy example graph output remains readable instead of being super verbose (#269)
• Compilation performance: the regex-automata dependency no longer enables the dfa-build feature by default. With dfa-build enabled, meta::Regex eagerly determinizes a full dense DFA for every small pattern, which dominated build time of simple class-containing patterns (e.g. \b(extern)\s+(crate) compiled ~4x slower than with the regex crate, which also ships without dfa-build); searches use the lazy DFA instead, with no measurable match-time difference (#272)
• Compilation performance: identical delegated fragments within one compile now share a single regex-automata engine instead of each building their own. Alternation-heavy patterns (TextMate grammar lookbehinds especially) often repeat the same fragment many times; on such patterns this removes a large share of build time (#277)

Fixed

• The playground didn't show when a literal or backreference was being matched case insensitively in the analysis tree view (#269)
• Seek patterns could become very large when recursive backrefs and subroutine calls were inlined, without bringing much benefit (#270)
• The optimize_nested_repeats pass could rewrite an optional capture group like (\w+)? into (\w*), causing an unmatched optional group to be reported as an empty match (Some("")) instead of None (#276)

[0.19.0] - 2026-07-28

Added

• Add BytesMode and the RegexInput trait so the matching and capture APIs can operate on strings or bytes, and allows to opt out of unicode handling if desired (#248)
  • Also allows searching within a range without slicing (#253)
  • Assertions can be overridden at runtime, if the regex builder allow_input_assertion_overrides option was used (#254)
  • Search can be performed in anchored mode, searching only at the start position specified (#263)
• Add experimental seek optimization to only invoke the VM at candidate positions where a match could occur (#246)
• Add RegexBuilder::disallow_empty_match_at_eof_after_newline to reject empty matches at the end of the haystack following a trailing newline, to match Oniguruma behavior (#247)
• Add RegexSet API for efficiently matching multiple patterns against the same text (#255)

Changed

• Case-insensitive backreference comparison of non-ASCII text now uses direct Unicode simple case folding instead of building a regex engine per comparison, which makes patterns like (?i)(\w+)\1 orders of magnitude faster on non-ASCII haystacks. The comparison is now strict fold equality over the captured text's byte-length window: a case-folded prefix of the window no longer counts as a match (previously a substring search could accept one and misalign the match end)
• Compilation performance: delegated regex-automata engines (including the whole pattern in the easy case) are now built from a directly-constructed Hir instead of a re-serialized pattern string, and RegexSet parses each pattern once for both of its set-wide engines instead of three times. This reduces compile time and peak compile memory, especially for RegexSet and small easy patterns
• Match performance: the backtracking VM's working memory (saves, backtrack stack, delegate slots) is pooled and reused across runs, making is_match/find/find_iter and RegexSet candidate verification allocation-free per call; RegexSet::find_input no longer allocates at failed candidate positions. Short and repeated matches improve substantially (up to ~30% for small patterns, ~10% for find_iter over many matches); single very long backtracking runs, where per-run setup is fully amortized anyway, can be a few percent slower
• Matches, CaptureMatches, Captures, and SubCaptureMatches are now generic over RegexInput, which is a breaking change for code that named these types explicitly (#248)
• Patterns no longer force Unicode mode during parsing, and inline (?u) / (?-u) flags are accepted when they agree with the builder configuration

Fixed

• Fix bug whereby inline flags were not overriding the builder options (#247)
• Fix bug whereby \G optimizations were applying where they shouldn't, giving wrong results (#256)
• Support Oniguruma quantifier parsing rules, whereby swapped ordering causes possessiveness, + only causes possessiveness after ?, * or + (#258)

Upgrade guide

If you previously stored i.e. Captures, you would need to change the type to Captures<str> to get the code to compile.

[0.18.0] - 2026-04-24

Added

• Add support for \N to mean any character except newline, for Oniguruma compatibility (#206)
• Add support for (*FAIL) backtracking control verb (#210)
• Add support for more \p{...} and \P{...} aliases, for Oniguruma compatibility (#207)
• Add support for word boundaries and zero-length fancy patterns inside variable lookbehinds (at top level) (#216)
• Add support for \R to mean general newline, matching all common line break characters, treating \r\n atomically (#220)
• Add support for the regex crate's (?R) CRLF mode flag (#238)

... (truncated)

Commits

• e268485 Version 0.19.2
• ee2e3a0 Merge pull request #281 from fancy-regex/leftmost_longest
• c9fa74e add another leftmost longest test assertion
• 797768f add leftmost_longest check to agents.md
• c323111 small refactor to avoid duplicating code
• c063e72 fix bug whereby leftmost longest match wasn't being returned when later, long...
• 04d8796 Update changelog
• 515397a add missing feature flag to documentation
• ba0416f small addition to contributing guide
• 4be8648 feat: gate leftmost_longest behind optional feature flag
• Additional commits viewable in compare view

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