# ERROR: File "setup.py" not found. Cannot perform editable install without a build backend.

- **ID:** `python/pip-editable-install-missing-pyproject`
- **Domain:** python
- **Category:** config_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

pip install -e . requires either setup.py or a [build-system] table in pyproject.toml to define an editable-capable backend.

## Version Compatibility

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

## Workarounds

1. **** (95% success)
   ```
   Add a build-system table to pyproject.toml: [build-system]\nrequires = ["setuptools>=61", "wheel"]\nbuild-backend = "setuptools.build_meta"
   ```
2. **** (90% success)
   ```
   Use a hatchling backend for pure-Python projects: [build-system]\nrequires = ["hatchling"]\nbuild-backend = "hatchling.build"
   ```
3. **** (92% success)
   ```
   Migrate to a PEP 621 [project] table and re-run pip install -e .
   ```

## Dead Ends

- **** — An empty setup.py declares no package metadata, so the editable install produces no importable package. (85% fail)
- **** — Disabling isolation does not provide a build backend; the error persists. (90% fail)
- **** — Installs a copy, so source edits are not reflected, defeating the purpose of -e. (70% fail)