What causes "No matching highlighting definition found" in microsoft/edit?

Add the file's extension/glob to the `paths` patterns of the appropriate .lsh entrypoint.

No matching highlighting definition found

Error message

No matching highlighting definition found

What it means

When a file path is given instead of a language ID, run_render picks the first entrypoint whose glob `paths` patterns match the path. If no loaded definition's path patterns match the file, it errors; the binary cannot guess a highlighting definition for the file.

Source

Thrown at crates/lsh-bin/src/main.rs:129

    path: Option<&Path>,
    language: Option<&str>,
) -> anyhow::Result<()> {
    let assembly = generator.assemble()?;

    let entrypoint = if let Some(language) = language {
        assembly.entrypoints.iter().find(|ep| ep.name.replace('_', "-") == language).ok_or_else(
            || anyhow::anyhow!("No highlighting definition found for language {language:?}"),
        )?
    } else if let Some(path) = path {
        assembly
            .entrypoints
            .iter()
            .find(|ep| {
                ep.paths.iter().any(|pattern| {
                    glob_match(pattern.as_bytes(), path.as_os_str().as_encoded_bytes())
                })
            })
            .ok_or_else(|| anyhow::anyhow!("No matching highlighting definition found"))?
    } else {
        bail!("A language ID is required when reading from stdin");
    };

    let mut color_map = Vec::new();
    let mut unknown_kinds = Vec::new();
    for hk in &assembly.highlight_kinds {
        let color = match hk.identifier {
            "other" => "",

            "comment" => "\x1b[32m",  // Green
            "method" => "\x1b[93m",   // Bright Yellow
            "string" => "\x1b[91m",   // Bright Red
            "variable" => "\x1b[96m", // Bright Cyan

            "constant.language" => "\x1b[94m",    // Bright Blue
            "constant.numeric" => "\x1b[92m",     // Bright Green
            "keyword.control" => "\x1b[95m",      // Bright Magenta

View on GitHub (pinned to 826b4c097b)

Solutions

Add the file's extension/glob to the `paths` patterns of the appropriate .lsh entrypoint.
Explicitly pass --language <id> instead of relying on path matching.
Load the definition set that covers the file type you are rendering.

Example fix

// before (in .lsh definition)
paths = ["*.rs"]
// after
paths = ["*.rs", "*.rs.in"]

Defensive patterns

Strategy: validation

Validate before calling

fn is_covered(path: &str, entrypoint_globs: &[&str]) -> bool {
    entrypoint_globs.iter().any(|g| glob_match(g.as_bytes(), path.as_bytes()))
}
if !is_covered("foo.weird-ext", &GLOBS) { eprintln!("no definition covers this file; pass --language"); }

Try / catch

// fall back to explicit language when path matching fails
let out = Command::new("lsh").arg(file).status()
    .or_else(|_| Command::new("lsh").args(["--language", "plaintext"]).arg(file).status())?;

Prevention

Add globs for every extension your project renders to the relevant .lsh `paths`.
Default to passing --language for files with uncommon extensions.
Add a test that renders each tracked file type so gaps surface early.

When it happens

Trigger: Rendering a file whose name/extension matches none of the loaded entrypoints' path glob patterns, e.g. an extension the .lsh definitions do not declare.

Common situations: Rendering files with unusual extensions (.txt, custom extensions); definitions loaded but their `paths` globs were authored for different extensions; new file types added before updating the .lsh definition.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of microsoft/edit@826b4c097b (2026-09-06). Data as JSON: /api/errors/7e402755f207c1d8. Report an issue: GitHub.