Pre-commit fails looking for python 3.6 interpreter in python 3.7.8 venv

An unexpected error has occurred: CalledProcessError: 
Command: ('/Users/as/.pyenv/versions/3.7.8/envs/ctixs/bin/python3.7', '-mvirtualenv', '/Users/as/.cache/pre-commit/repo2jxgpyes/py_env-python3.6', '-p', 'python3.6')
Return code: 1
Expected return code: 0
Output:
    RuntimeError: failed to find interpreter for Builtin discover of python_spec='python3.6'

Errors: (none)

Traceback (most recent call last):
  File "/Users/as/.pyenv/versions/3.7.8/envs/ctixs/lib/python3.7/site-packages/pre_commit/error_handler.py", line 46, in error_handler
    yield
  File "/Users/as/.pyenv/versions/3.7.8/envs/ctixs/lib/python3.7/site-packages/pre_commit/main.py", line 316, in main
    return run(args.config, store, args)
  File "/Users/as/.pyenv/versions/3.7.8/envs/ctixs/lib/python3.7/site-packages/pre_commit/commands/run.py", line 295, in run
    install_hook_envs(hooks, store)
  File "/Users/as/.pyenv/versions/3.7.8/envs/ctixs/lib/python3.7/site-packages/pre_commit/repository.py", line 215, in install_hook_envs
    hook.install()
  File "/Users/as/.pyenv/versions/3.7.8/envs/ctixs/lib/python3.7/site-packages/pre_commit/repository.py", line 93, in install
    self.prefix, self.language_version, self.additional_dependencies,
  File "/Users/as/.pyenv/versions/3.7.8/envs/ctixs/lib/python3.7/site-packages/pre_commit/languages/python.py", line 161, in install_environment
    _make_venv(env_dir, python)
  File "/Users/as/.pyenv/versions/3.7.8/envs/ctixs/lib/python3.7/site-packages/pre_commit/languages/python.py", line 173, in make_venv
    cmd_output(*cmd, env=env, cwd='/')
  File "/Users/as/.pyenv/versions/3.7.8/envs/ctixs/lib/python3.7/site-packages/pre_commit/util.py", line 153, in cmd_output
    returncode, cmd, retcode, output=(stdout, stderr),
pre_commit.util.CalledProcessError: Command: ('/Users/as/.pyenv/versions/3.7.8/envs/ctixs/bin/python3.7', '-mvirtualenv', '/Users/as/.cache/pre-commit/repo2jxgpyes/py_env-python3.6', '-p', 'python3.6')
Return code: 1
Expected return code: 0
Output:
    RuntimeError: failed to find interpreter for Builtin discover of python_spec='python3.6'

Errors: (none)

[rkm]

Can you post your full config, please? This seems similar to #1375, and I’ve also seen this myself when a hook is set to look for a different python version than is available.

[asottile]

please don’t report here, report to virtualenv – thanks!