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

- **ID:** `python/setuptools-version-parse-error-invalid-requirement`
- **Domain:** python
- **Category:** data_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

A requirement string contains two version specifiers without a comma (e.g. `>=1.0<2.0`), which the PEP 508 parser rejects.

## 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)
   ```
   Insert a comma between specifiers: `foo>=1.0,<2.0` in install_requires / pyproject.toml.
   ```
2. **** (90% success)
   ```
   Validate requirements with `python -c "from packaging.requirements import Requirement; Requirement('foo>=1.0,<2.0')"` before packaging.
   ```

## Dead Ends

- **** — They are not shell metacharacters inside a Python string; escaping does nothing. (90% fail)
- **** — The string is genuinely malformed regardless of parser version. (80% fail)