diff --git a/pre_commit/commands/hook_impl.py b/pre_commit/commands/hook_impl.py index 5ff4555e..4843fc77 100644 --- a/pre_commit/commands/hook_impl.py +++ b/pre_commit/commands/hook_impl.py @@ -147,15 +147,44 @@ def _pre_push_ns( return None +_EXPECTED_ARG_LENGTH_BY_HOOK = { + 'commit-msg': 1, + 'post-checkout': 3, + 'pre-commit': 0, + 'pre-merge-commit': 0, + 'pre-push': 2, +} + + +def _check_args_length(hook_type: str, args: Sequence[str]) -> None: + if hook_type == 'prepare-commit-msg': + if len(args) < 1 or len(args) > 3: + raise SystemExit( + f'hook-impl for {hook_type} expected 1, 2, or 3 arguments ' + f'but got {len(args)}: {args}', + ) + elif hook_type in _EXPECTED_ARG_LENGTH_BY_HOOK: + expected = _EXPECTED_ARG_LENGTH_BY_HOOK[hook_type] + if len(args) != expected: + arguments_s = 'argument' if expected == 1 else 'arguments' + raise SystemExit( + f'hook-impl for {hook_type} expected {expected} {arguments_s} ' + f'but got {len(args)}: {args}', + ) + else: + raise AssertionError(f'unexpected hook type: {hook_type}') + + def _run_ns( hook_type: str, color: bool, args: Sequence[str], stdin: bytes, ) -> Optional[argparse.Namespace]: + _check_args_length(hook_type, args) if hook_type == 'pre-push': return _pre_push_ns(color, args, stdin) - elif hook_type in {'prepare-commit-msg', 'commit-msg'}: + elif hook_type in {'commit-msg', 'prepare-commit-msg'}: return _ns(hook_type, color, commit_msg_filename=args[0]) elif hook_type in {'pre-merge-commit', 'pre-commit'}: return _ns(hook_type, color) diff --git a/tests/commands/hook_impl_test.py b/tests/commands/hook_impl_test.py index 032fa8fa..ddf65b77 100644 --- a/tests/commands/hook_impl_test.py +++ b/tests/commands/hook_impl_test.py @@ -89,6 +89,51 @@ def test_run_legacy_recursive(tmpdir): call() +@pytest.mark.parametrize( + ('hook_type', 'args'), + ( + ('pre-commit', []), + ('pre-merge-commit', []), + ('pre-push', ['branch_name', 'remote_name']), + ('commit-msg', ['.git/COMMIT_EDITMSG']), + ('post-checkout', ['old_head', 'new_head', '1']), + # multiple choices for commit-editmsg + ('prepare-commit-msg', ['.git/COMMIT_EDITMSG']), + ('prepare-commit-msg', ['.git/COMMIT_EDITMSG', 'message']), + ('prepare-commit-msg', ['.git/COMMIT_EDITMSG', 'commit', 'deadbeef']), + ), +) +def test_check_args_length_ok(hook_type, args): + hook_impl._check_args_length(hook_type, args) + + +def test_check_args_length_error_too_many_plural(): + with pytest.raises(SystemExit) as excinfo: + hook_impl._check_args_length('pre-commit', ['run', '--all-files']) + msg, = excinfo.value.args + assert msg == ( + 'hook-impl for pre-commit expected 0 arguments but got 2: ' + "['run', '--all-files']" + ) + + +def test_check_args_length_error_too_many_singluar(): + with pytest.raises(SystemExit) as excinfo: + hook_impl._check_args_length('commit-msg', []) + msg, = excinfo.value.args + assert msg == 'hook-impl for commit-msg expected 1 argument but got 0: []' + + +def test_check_args_length_prepare_commit_msg_error(): + with pytest.raises(SystemExit) as excinfo: + hook_impl._check_args_length('prepare-commit-msg', []) + msg, = excinfo.value.args + assert msg == ( + 'hook-impl for prepare-commit-msg expected 1, 2, or 3 arguments ' + 'but got 0: []' + ) + + def test_run_ns_pre_commit(): ns = hook_impl._run_ns('pre-commit', True, (), b'') assert ns is not None