# packaging.version.InvalidVersion: Invalid version: '1.0.0.post'

- **ID:** `python/pip-version-parse-legacy-epoch`
- **Domain:** python
- **Category:** data_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

A package published a version string that violates PEP 440 (e.g. trailing '.post' without a number), causing packaging.version to raise during resolution.

## 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)
   ```
   pip install https://files.pythonhosted.org/packages/.../somepkg-1.0.0-py3-none-any.whl
   ```
2. **** (70% success)
   ```
   pip install --upgrade pip packaging
pip install somepkg
   ```

## Dead Ends

- **** — The malformed version is not a pre-release; parsing still fails before any filter applies. (90% fail)
- **** — If the index metadata includes the malformed version, pip still parses all versions and errors. (75% fail)