# ERROR: Invalid constraint line in constraints.txt: 'package1' - Expected a version specifier

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

## Root Cause

A constraint file must contain package names with version specifiers (e.g., package1>=1.0), but a bare package name was found.

## Version Compatibility

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

## Workarounds

1. **** (95% success)
   ```
   echo 'package1>=1.0' >> constraints.txt
   ```
2. **** (90% success)
   ```
   sed -i '/^package1$/d' constraints.txt
   ```

## Dead Ends

- **** — Comments are ignored; the invalid line still causes error. (100% fail)
- **** — Constraints files have different syntax; using them as requirements may fail. (60% fail)