[kolkov]

Summary

• Remove 0x80–0xFF single-byte range from coversAllNonASCII path in NFA compiler
• This range caused negated classes (\S, \D, \W, [^x]) to match individual bytes of valid multi-byte UTF-8 runes — e.g. \S{2} matched single Cyrillic К (2 bytes)
• Invalid UTF-8 byte handling deferred to fix: invalid UTF-8 bytes silently skipped instead of matching as U+FFFD #179 (look-ahead design)
• Random-fuzz divergence: 0.75% → 0.21%

Test plan

• 7 MatchString tests: single rune vs multi-repetition (2-byte Cyrillic, 3-byte CJK, 4-byte emoji)
• 6 FindAllString tests: rune-counted matches, not byte-split fragments
• 3 FindAllStringIndex tests: byte-correct boundaries
• Full suite green (go test ./... -short)
• Lint clean, gofmt clean

Fixes #174

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[github-actions]

Benchmark Comparison

Comparing main → PR #180

Summary: geomean 95.17n 92.96n -2.32%

⚠️ Potential regressions detected:

geomean                               ³                +0.00%               ³
geomean                               ³                +0.00%               ³
geomean              30.01n         30.04n        +0.12%
geomean                         ³                +0.00%               ³
geomean                         ³                +0.00%               ³
AhoCorasickManyPatterns/coregex_10_patterns-4           37.12n ± ∞ ¹    39.35n ± ∞ ¹    +6.01% (p=0.008 n=5)
AhoCorasickManyPatterns/coregex_25_patterns-4           44.54n ± ∞ ¹    47.42n ± ∞ ¹    +6.47% (p=0.008 n=5)
AhoCorasickManyPatterns/coregex_50_patterns-4           38.80n ± ∞ ¹    40.71n ± ∞ ¹    +4.92% (p=0.008 n=5)
AnchoredLiteralVsStdlib/stdlib_long-4                   373.7n ± ∞ ¹    376.1n ± ∞ ¹    +0.64% (p=0.008 n=5)
ASCIIOptimization_Issue79/short_WithASCII-4             223.5n ± ∞ ¹    223.8n ± ∞ ¹    +0.13% (p=0.024 n=5)

Full results available in workflow artifacts. CI runners have ~10-20% variance.
For accurate benchmarks, run locally: ./scripts/bench.sh --compare