# packaging.requirements.InvalidRequirement: Expected end or semicolon (after version specifier)
    foo >= 1.0 < 2.0
        ~~~~^

- **ID:** `python/setuptools-invalid-version-specifier`
- **Domain:** python
- **Category:** config_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

A version constraint combines two operators without a comma, e.g. '>= 1.0 < 2.0'. PEP 440 requires a comma between specifiers.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.x | active | — | — |

## Workarounds

1. **** (99% success)
   ```
   # bad
foo >= 1.0 < 2.0
# good
foo>=1.0,<2.0
   ```
2. **** (95% success)
   ```
   # equivalent to >=1.0,<2.0 for a 1.x series
foo~=1.0
   ```

## Dead Ends

- **** — Quoting does not change the grammar the parser enforces. (90% fail)
- **** — Older packaging also rejects the same malformed specifier. (85% fail)