rust parsing_error ai_generated true

regex::Error: CompiledTooBig: compiled regex exceeds size limit

ID: rust/rust-regex-compile-error

Also available as: JSON · Markdown
85%Fix Rate
87%Confidence
50Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1 active — — —

Root Cause

The regex pattern is either invalid or exceeds the default size limit. Simplify the pattern or increase the limit.

generic

Workarounds

  1. 88% success Increase the size limit with RegexBuilder 
    use regex::RegexBuilder;
let re = RegexBuilder::new(pattern)
    .size_limit(10 * (1 << 20)) // 10MB
    .build()?;

    Sources: https://docs.rs/regex/latest/regex/struct.RegexBuilder.html

  2. 90% success Use lazy_static or once_cell to compile regex once 
    use std::sync::LazyLock;
static RE: LazyLock<regex::Regex> = LazyLock::new(|| {
    regex::Regex::new(r"pattern").unwrap()
});

    Sources: https://docs.rs/regex/latest/regex/#example-avoid-compiling-the-same-regex-in-a-loop

Dead Ends

Common approaches that don't work:

  1. Set the size limit to usize::MAX 70% fail

    Massive regexes consume excessive memory and CPU; potential denial of service

Error Chain

Leads to:
Preceded by:
Frequently confused with: