Description

When oxfmt is run with target paths or glob patterns, but a .prettierignore (or .gitignore) rule excludes all matched files, the error message is:

Expected at least one target file

This message implies that no files were found matching the given paths/globs, when in reality files do exist and match — they are just being excluded by an ignore rule. This makes the root cause extremely difficult to diagnose, especially when .prettierignore was set up for a previous Prettier-based workflow and the user is unaware that oxfmt reads it by default.

Reproduction

1. Create a project with some .md files
2. Add a .prettierignore with the following rules:

   /**/*.*
   !*.svg
   

3. Run:

   npx oxfmt '**/*.md'

4. Observe:

   Expected at least one target file
   

The same happens with npx oxfmt . or even npx oxfmt README.md — any invocation where files exist but are fully excluded by the ignore file. Note that .md files are excluded by the /**/*.* rule and are not re-included by the !*.svg negation, so all targets end up excluded.

Expected behavior

The error message should indicate why no files were processed. For example:

No files to format. All matched files were excluded by ignore rules.
Ignore sources: .prettierignore, .gitignore
Hint: Use --ignore-path to override the default ignore files, or --no-error-on-unmatched-pattern to suppress this error.

Or at minimum:

Expected at least one target file (all candidates were excluded by .prettierignore)

This would immediately point the user toward the root cause.

Context

This is a common scenario when migrating from Prettier to Biome + oxfmt. Projects that used Biome for JS/TS formatting often have a .prettierignore like:

/**/*.*
!*.svg

This is intended to prevent Prettier from running on most files while still allowing SVGs to be formatted. When oxfmt is later added to format non-JS files (Markdown, YAML, CSS), the leftover .prettierignore silently blocks everything that isn't an SVG, with no hint in the error output.

The --ignore-path flag is the correct workaround, but discovering it requires significant debugging since the error message gives no hint about ignore files being involved.

Environment

• oxfmt version: 0.41.0
• OS: Linux (x64)
• Node.js: v25