# ERROR: Invalid requirement: 'Requires-Python: >=3.8'

- **ID:** `python/pip-requires-python-invalid-metadata`
- **Domain:** python
- **Category:** config_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

A requirements.txt file contains package metadata lines (like Requires-Python or Name:) pasted from a PKG-INFO; pip's requirement parser rejects them.

## Version Compatibility

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

## Workarounds

1. **** (98% success)
   ```
   # requirements.txt should look like:
requests>=2.31
numpy==1.26.4
# Remove any 'Name:', 'Version:', 'Requires-Python:' lines.
   ```
2. **** (95% success)
   ```
   pip freeze > requirements.txt
# verify each line parses
python - <<'PY'
from packaging.requirements import Requirement
for i, l in enumerate(open('requirements.txt'),1):
    l=l.strip()
    if l and not l.startswith('#'):
        Requirement(l)
print('ok')
PY
   ```

## Dead Ends

- **** — If other metadata lines remain, parsing still fails; also hides the actual intent of the file. (60% fail)
- **** — --no-deps skips dependency resolution, not requirement parsing; the invalid line still errors. (90% fail)