find::glob_util — glob pattern helpers

Shared pattern utilities used by both glob and grep (when grep.glob is set). If you only call glob / grep, you never need this module directly — but it is public because it is genuinely useful on its own for building patterns.

pub fn build_glob_pattern(glob: &str, recursive: bool) -> String
pub fn compile_glob(glob: &str, recursive: bool) -> Result<GlobSet, String>
pub fn try_compile_glob(glob: Option<&str>, recursive: bool) -> Result<Option<GlobSet>, String>

build_glob_pattern — the normalization rules

Turns a raw pattern string into a compiled-ready one:

1. Backslashes become forward slashes — "src\\**\\*.ts" → "src/**/*.ts" (Windows-style input works everywhere).
2. Recursive prefix — when recursive is true and the pattern has no /, does not start with **, and is not an exact brace union, it gets "**/" prepended: "*.ts" → "**/*.ts". An exact brace union like "{alpha.txt,beta.txt}" (braces only, no wildcards) is treated as a list of literal filenames and left alone.
3. Unclosed braces are closed — "*.{ts,tsx" → "*.{ts,tsx}", and nested cases like "{a,{b,c}" → "{a,{b,c}}". This is a deliberate tolerance: LLMs occasionally emit patterns without the closing }.

compile_glob — pattern → matcher

Compiles a single pattern string into a globset::GlobSet using build_glob_pattern first, with literal_separator(true) — meaning * never crosses a / boundary. Errors are prefixed Invalid glob pattern: ... or Failed to build glob matcher: ....

try_compile_glob — the optional variant

Same as compile_glob, but takes Option<&str> and returns Ok(None) when the input is None, empty, or whitespace-only — exactly the shape grep needs for its optional glob filter.

Next: grep — searching by content.