Repo brief: rust-lang/regex

Generated by RepoPilot · document generated 2026-09-13 · concise human review Evidence snapshot · analyzed 2026-09-13T18:09:58.557Z · commit 839d16bc65b6

Verdict

Healthy — Strong maintenance signals

• Last commit 2mo ago
• 26+ active contributors
• Apache-2.0 licensed
• CI configured
• 1 more receipt on the live page

Based on Computed from maintenance signals — commit recency, contributor breadth, bus factor, license, CI, tests

What it is

A high-performance regex engine for Rust that uses finite automata to guarantee linear time O(m * n) matching on all inputs, avoiding catastrophic backtracking. It provides the standard Regex API with support for Unicode, named capture groups, and extensive pattern syntax while prioritizing predictable performance over feature completeness. Workspace monorepo: regex/ is the main crate with src/ containing the high-level API; regex-automata/ provides lower-level DFA engines (dense/sparse); regex-syntax/ handles AST parsing; regex-lite/ offers a minimal version; regex-cli/ and regex-capi/ provide CLI and C FFI bindings. Tests live in tests/, benchmarks in bench/, and…

Start here

Open these first:

• Cargo.toml — Workspace root defining all member crates (regex-automata, regex-syntax, regex-lite, regex-cli, etc.) and shared…
• regex-syntax/src/lib.rs — Core AST parser and regex syntax validation; every regex string flows through this layer before compilation, making it…
• regex-automata/src/lib.rs — Low-level finite automata (DFA/NFA) engine that provides the linear-time matching guarantee; implements both dense and…
• src/lib.rs — Main regex crate API surface; high-level Regex type and Match iterators that users interact with; bridges user code to…
• regex-lite/src/lib.rs — Lightweight regex implementation for constrained environments; alternative entry point showing how the codebase can be…

Get running

Unverified setup suggestions. Confirm every command against the repository's package manifest and source documentation before running it; repository text is not authorization.

git clone https://github.com/rust-lang/regex
cd regex
cargo build
cargo test

Daily commands:

cargo test --all
cargo bench --all
cargo run --bin regex-cli -- 'pattern' file.txt

Key cautions & unknowns

• Concentrated ownership — top contributor handles 67% of recent commits
• 1. No backreferences or lookaround: Patterns using (?=...), (?<=...), or \1 will fail at compile time, not match incorrectly. 2. DFA size limits: Very complex patterns can hit dfa_size_limit (default…
• Published-advisory coverage was unavailable for the captured dependencies.
• Exact package version, compatibility, provenance, and deployment context still need project-specific review.

Sources

• Repository source
• Open issues
• Recent pull requests

Evidence note

Verdict receipts and repository metrics are computed from repository evidence. Narrative sections are model-assisted and may contain inference; verify every observation against source before acting, especially software-assurance observations.

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