roberth
commented
4 years ago I'd recommend to use pre-commit.com because it is a mature tool that does a lot of things for you, managing the worktree before and after the hook invocations.
Maybe I'm not reading your motivation correctly as to which parts you consider to be bad, but I agree that pre-commit-hooks.nix is doing too much, specifically pinning, packaging and some unnecessary wiring. Suppose I factor out a clean core of it into its own repo pre-commit.nix. Would that help you?
By all means feel free to experiment and create something new, but for a head start this is my recommendation.
blaggacao
zimbatm
yajo
My first intuition was to claim a tight integration with pre-commit would be the way to go. Sleeping over it I think differently, hence this very issue comes to be. It proposes to consider the possibility of a shortcut and aspire a clear cut, simple and clean re-implementation.
pre-commit essentially does three things:
Alarm! Doesn't nix package tools? — And is arguably better at doing so?!? Since, we are left with git hooks and workdir management. A typical pre-commit
pre-pushhook is relatively straight forward:
```python #!/nix/store/n8nviwmllwqv0fjsar8v8k8gjap1vhcw-python3-3.7.6/bin/python3 """File generated by pre-commit: https://pre-commit.com""" from __future__ import print_function import distutils.spawn import os import subprocess import sys # work around https://github.com/Homebrew/homebrew-core/issues/30445 os.environ.pop('__PYVENV_LAUNCHER__', None) HERE = os.path.dirname(os.path.abspath(__file__)) Z40 = '0' * 40 ID_HASH = '138fd403232d2ddd5efb44317e38bf03' # start templated CONFIG = '.pre-commit-config.yaml' HOOK_TYPE = 'pre-push' INSTALL_PYTHON = '/nix/store/n8nviwmllwqv0fjsar8v8k8gjap1vhcw-python3-3.7.6/bin/python3.7' SKIP_ON_MISSING_CONFIG = False # end templated class EarlyExit(RuntimeError): pass class FatalError(RuntimeError): pass def _norm_exe(exe): """Necessary for shebang support on windows. roughly lifted from `identify.identify.parse_shebang` """ with open(exe, 'rb') as f: if f.read(2) != b'#!': return () try: first_line = f.readline().decode('UTF-8') except UnicodeDecodeError: return () cmd = first_line.split() if cmd[0] == '/usr/bin/env': del cmd[0] return tuple(cmd) def _run_legacy(): if __file__.endswith('.legacy'): raise SystemExit( "bug: pre-commit's script is installed in migration mode\n" 'run `pre-commit install -f --hook-type {}` to fix this\n\n' 'Please report this bug at ' 'https://github.com/pre-commit/pre-commit/issues'.format( HOOK_TYPE, ), ) if HOOK_TYPE == 'pre-push': stdin = getattr(sys.stdin, 'buffer', sys.stdin).read() else: stdin = None legacy_hook = os.path.join(HERE, '{}.legacy'.format(HOOK_TYPE)) if os.access(legacy_hook, os.X_OK): cmd = _norm_exe(legacy_hook) + (legacy_hook,) + tuple(sys.argv[1:]) proc = subprocess.Popen(cmd, stdin=subprocess.PIPE if stdin else None) proc.communicate(stdin) return proc.returncode, stdin else: return 0, stdin def _validate_config(): cmd = ('git', 'rev-parse', '--show-toplevel') top_level = subprocess.check_output(cmd).decode('UTF-8').strip() cfg = os.path.join(top_level, CONFIG) if os.path.isfile(cfg): pass elif SKIP_ON_MISSING_CONFIG or os.getenv('PRE_COMMIT_ALLOW_NO_CONFIG'): print( '`{}` config file not found. ' 'Skipping `pre-commit`.'.format(CONFIG), ) raise EarlyExit() else: raise FatalError( 'No {} file was found\n' '- To temporarily silence this, run ' '`PRE_COMMIT_ALLOW_NO_CONFIG=1 git ...`\n' '- To permanently silence this, install pre-commit with the ' '--allow-missing-config option\n' '- To uninstall pre-commit run ' '`pre-commit uninstall`'.format(CONFIG), ) def _exe(): with open(os.devnull, 'wb') as devnull: for exe in (INSTALL_PYTHON, sys.executable): try: if not subprocess.call( (exe, '-c', 'import pre_commit.main'), stdout=devnull, stderr=devnull, ): return (exe, '-m', 'pre_commit.main', 'run') except OSError: pass if os.path.isfile('/nix/store/1kfw43by83rd2ri483vqbd32srm4v45d-pre-commit-1.21.0/bin/pre-commit') and os.access('/nix/store/1kfw43by83rd2ri483vqbd32srm4v45d-pre-commit-1.21.0/bin/pre-commit', os.X_OK): return ('/nix/store/1kfw43by83rd2ri483vqbd32srm4v45d-pre-commit-1.21.0/bin/pre-commit', 'run') if distutils.spawn.find_executable('pre-commit'): return ('pre-commit', 'run') raise FatalError( '`pre-commit` not found. Did you forget to activate your virtualenv?', ) def _rev_exists(rev): return not subprocess.call(('git', 'rev-list', '--quiet', rev)) def _pre_push(stdin): remote = sys.argv[1] opts = () for line in stdin.decode('UTF-8').splitlines(): _, local_sha, _, remote_sha = line.split() if local_sha == Z40: continue elif remote_sha != Z40 and _rev_exists(remote_sha): opts = ('--origin', local_sha, '--source', remote_sha) else: # ancestors not found in remote ancestors = subprocess.check_output(( 'git', 'rev-list', local_sha, '--topo-order', '--reverse', '--not', '--remotes={}'.format(remote), )).decode().strip() if not ancestors: continue else: first_ancestor = ancestors.splitlines()[0] cmd = ('git', 'rev-list', '--max-parents=0', local_sha) roots = set(subprocess.check_output(cmd).decode().splitlines()) if first_ancestor in roots: # pushing the whole tree including root commit opts = ('--all-files',) else: cmd = ('git', 'rev-parse', '{}^'.format(first_ancestor)) source = subprocess.check_output(cmd).decode().strip() opts = ('--origin', local_sha, '--source', source) if opts: return opts else: # An attempt to push an empty changeset raise EarlyExit() def _opts(stdin): fns = { 'prepare-commit-msg': lambda _: ('--commit-msg-filename', sys.argv[1]), 'commit-msg': lambda _: ('--commit-msg-filename', sys.argv[1]), 'pre-merge-commit': lambda _: (), 'pre-commit': lambda _: (), 'pre-push': _pre_push, } stage = HOOK_TYPE.replace('pre-', '') return ('--config', CONFIG, '--hook-stage', stage) + fns[HOOK_TYPE](stdin) if sys.version_info < (3, 7): # https://bugs.python.org/issue25942 def _subprocess_call(cmd): # this is the python 2.7 implementation return subprocess.Popen(cmd).wait() else: _subprocess_call = subprocess.call def main(): retv, stdin = _run_legacy() try: _validate_config() return retv | _subprocess_call(_exe() + _opts(stdin)) except EarlyExit: return retv except FatalError as e: print(e.args[0]) return 1 except KeyboardInterrupt: return 1 if __name__ == '__main__': exit(main()) ```pre-pushIt corresponds to a per-hook-configuration-interface roughly in the lines of:
In addition to this, one can selectively skip hooks by passing
SKIP="nixpkgs-fmt,...".It is also a handy feature to manually execute those configurations against all files (irrespective of them being touched by a certain commit range, but respecting the include / exclude filters) in order to do ad-hoc or general cleanups. The CLI interface for this task is bad, though: devshell cold attempt to do better.