# ERROR: Cannot install -r requirements.txt and foo==1.0 because these package versions have conflicting dependencies.

ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts

- **ID:** `python/pip-legacy-setup-py-install-removed`
- **Domain:** python
- **Category:** install_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The modern pip resolver cannot find any version set satisfying all pinned constraints, often due to over-pinned requirements or transitive version pins that contradict each other.

## Version Compatibility

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

## Workarounds

1. **** (80% success)
   ```
   Relax pins to ranges (`foo>=1.0,<2`) and re-resolve; use `pip install -r requirements.txt --dry-run` to preview.
   ```
2. **** (90% success)
   ```
   Use a resolver-aware tool: `pip-compile requirements.in` or `uv pip compile` to compute a consistent lockfile.
   ```

## Dead Ends

- **** — Installs incompatible versions and only defers the failure to runtime. (60% fail)
- **** — May break reproducibility and still conflict transitively. (50% fail)