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https://github.com/pre-commit/pre-commit-hooks.git
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a17514d55e
This change adds an advisory mode via `--check` that only warns of formatting issues with files, but does not address them. This support is desirable because--while I don't mind the automagic changes when done in a mechanical way--some individuals who I described the current behavior of these fixers to were a bit uneasy about the magic that went along with them. Adding `--check` so others can opt out (similar to `black --check`) is a compromise on this front. Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>
85 lines
2.7 KiB
Python
85 lines
2.7 KiB
Python
from __future__ import print_function
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from __future__ import unicode_literals
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import argparse
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import os
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import sys
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from typing import IO
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from typing import Optional
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from typing import Sequence
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def fix_file(file_obj, apply_fixes=True): # type: (IO[bytes], bool) -> int
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# Test for newline at end of file
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# Empty files will throw IOError here
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try:
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file_obj.seek(-1, os.SEEK_END)
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except IOError:
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return 0
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last_character = file_obj.read(1)
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# last_character will be '' for an empty file
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if last_character not in {b'\n', b'\r'} and last_character != b'':
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# Needs this seek for windows, otherwise IOError
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if apply_fixes:
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file_obj.seek(0, os.SEEK_END)
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file_obj.write(b'\n')
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return 1
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while last_character in {b'\n', b'\r'}:
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# Deal with the beginning of the file
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if file_obj.tell() == 1:
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# If we've reached the beginning of the file and it is all
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# linebreaks then we can make this file empty
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if apply_fixes:
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file_obj.seek(0)
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file_obj.truncate()
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return 1
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# Go back two bytes and read a character
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file_obj.seek(-2, os.SEEK_CUR)
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last_character = file_obj.read(1)
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# Our current position is at the end of the file just before any amount of
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# newlines. If we find extraneous newlines, then backtrack and trim them.
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position = file_obj.tell()
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remaining = file_obj.read()
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for sequence in (b'\n', b'\r\n', b'\r'):
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if remaining == sequence:
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return 0
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elif remaining.startswith(sequence):
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if apply_fixes:
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file_obj.seek(position + len(sequence))
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file_obj.truncate()
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return 1
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return 0
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def main(argv=None): # type: (Optional[Sequence[str]]) -> int
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parser = argparse.ArgumentParser()
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parser.add_argument(
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'--check', action='store_true',
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help="Don't write the files back. Returns a non-zero code if changes "
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'would be applied. Returns zero if no changes are required.',
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)
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parser.add_argument('filenames', nargs='*', help='Filenames to fix')
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args = parser.parse_args(argv)
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retv = 0
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for filename in args.filenames:
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# Read as binary so we can read byte-by-byte
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with open(filename, 'rb+') as file_obj:
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ret_for_file = fix_file(file_obj, apply_fixes=not args.check)
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if ret_for_file:
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if args.check:
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print('Would fix {}'.format(filename))
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else:
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print('Fixing {}'.format(filename))
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retv |= ret_for_file
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return retv
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if __name__ == '__main__':
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sys.exit(main())
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