# ERROR: ResolutionImpossible: Cannot install package-a and package-b because these package versions have conflicting dependencies.

- **ID:** `python/pip-resolver-backtracking-too-deep`
- **Domain:** python
- **Category:** install_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

pip's dependency resolver (resolvelib) cannot find a set of package versions satisfying all constraints. This often occurs with transitive dependencies requiring mutually exclusive versions.

## Version Compatibility

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

## Workarounds

1. **** (80% success)
   ```
   pip install 'package-a==1.2.0' 'package-b==2.0.0'  # choose versions with compatible deps
   ```
2. **** (60% success)
   ```
   pip install --use-deprecated=legacy-resolver package-a package-b
   ```

## Dead Ends

- **** — --force-reinstall reinstalls but does not resolve version conflicts; the resolver still fails. (90% fail)
- **** — Cache clearing does not change dependency metadata; the conflict remains. (85% fail)