# ERROR: Invalid requirement: 'package==1.0+local' (from line 1 of requirements.txt)

- **ID:** `python/pip-install-error-local-version-identifier`
- **Domain:** python
- **Category:** config_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The requirement specifies a local version identifier (e.g., 1.0+local) which is not allowed in requirements files unless the package is available from a local index or direct URL.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.7 | active | — | — |
| 3.8 | active | — | — |
| 3.9 | active | — | — |
| 3.10 | active | — | — |

## Workarounds

1. **** (85% success)
   ```
   Specify the package with a direct URL: package @ https://example.com/package-1.0+local.tar.gz.
   ```
2. **** (80% success)
   ```
   Use a local index: pip install --index-url file:///path/to/index package==1.0+local.
   ```

## Dead Ends

- **** — May install a different version than intended, causing compatibility issues. (70% fail)
- **** — Does not affect local version identifiers; still invalid. (90% fail)