# warning: no previously-included files matching '*.pyc' found under directory '*'
warning: no files found matching '*.json' under directory 'data'

- **ID:** `python/setuptools-manifest-in-missing-files`
- **Domain:** python
- **Category:** data_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

MANIFEST.in references files or globs that do not exist in the source tree, so the sdist silently omits data files the package needs at runtime.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.8 | active | — | — |
| 3.9 | active | — | — |
| 3.10 | active | — | — |
| 3.11 | active | — | — |
| 3.12 | active | — | — |

## Workarounds

1. **** (90% success)
   ```
   Verify paths exist relative to the project root and correct MANIFEST.in, e.g. `recursive-include src/pkg/data *.json`. Rebuild with `python -m build`.
   ```
2. **** (85% success)
   ```
   Prefer `[tool.setuptools.package-data]` in pyproject.toml to declare data files instead of relying on MANIFEST.in.
   ```

## Dead Ends

- **** — The resulting sdist lacks data files, causing runtime FileNotFoundError for users. (70% fail)
- **** — If the paths are wrong, additional globs produce more warnings without including files. (65% fail)