pre-commit-hooks: python3.6+

pre_commit_hooks/fix_encoding_pragma.py

@@ -1,18 +1,13 @@
-from __future__ import absolute_import
-from __future__ import print_function
-from __future__ import unicode_literals
-
 import argparse
-import collections
 from typing import IO
+from typing import NamedTuple
 from typing import Optional
 from typing import Sequence
-from typing import Union
 
 DEFAULT_PRAGMA = b'# -*- coding: utf-8 -*-'
 
 
-def has_coding(line):  # type: (bytes) -> bool
+def has_coding(line: bytes) -> bool:
     if not line.strip():
         return False
     return (
@@ -25,30 +20,30 @@ def has_coding(line):  # type: (bytes) -> bool
     )
 
 
-class ExpectedContents(
-        collections.namedtuple(
-            'ExpectedContents', ('shebang', 'rest', 'pragma_status', 'ending'),
-        ),
-):
-    """
-    pragma_status:
-    - True: has exactly the coding pragma expected
-    - False: missing coding pragma entirely
-    - None: has a coding pragma, but it does not match
-    """
-    __slots__ = ()
+class ExpectedContents(NamedTuple):
+    shebang: bytes
+    rest: bytes
+    # True: has exactly the coding pragma expected
+    # False: missing coding pragma entirely
+    # None: has a coding pragma, but it does not match
+    pragma_status: Optional[bool]
+    ending: bytes
 
     @property
-    def has_any_pragma(self):  # type: () -> bool
+    def has_any_pragma(self) -> bool:
         return self.pragma_status is not False
 
-    def is_expected_pragma(self, remove):  # type: (bool) -> bool
+    def is_expected_pragma(self, remove: bool) -> bool:
         expected_pragma_status = not remove
         return self.pragma_status is expected_pragma_status
 
 
-def _get_expected_contents(first_line, second_line, rest, expected_pragma):
-    # type: (bytes, bytes, bytes, bytes) -> ExpectedContents
+def _get_expected_contents(
+        first_line: bytes,
+        second_line: bytes,
+        rest: bytes,
+        expected_pragma: bytes,
+) -> ExpectedContents:
     ending = b'\r\n' if first_line.endswith(b'\r\n') else b'\n'
 
     if first_line.startswith(b'#!'):
@@ -60,7 +55,7 @@ def _get_expected_contents(first_line, second_line, rest, expected_pragma):
         rest = second_line + rest
 
     if potential_coding.rstrip(b'\r\n') == expected_pragma:
-        pragma_status = True  # type: Optional[bool]
+        pragma_status: Optional[bool] = True
     elif has_coding(potential_coding):
         pragma_status = None
     else:
@@ -72,8 +67,11 @@ def _get_expected_contents(first_line, second_line, rest, expected_pragma):
     )
 
 
-def fix_encoding_pragma(f, remove=False, expected_pragma=DEFAULT_PRAGMA):
-    # type: (IO[bytes], bool, bytes) -> int
+def fix_encoding_pragma(
+        f: IO[bytes],
+        remove: bool = False,
+        expected_pragma: bytes = DEFAULT_PRAGMA,
+) -> int:
     expected = _get_expected_contents(
         f.readline(), f.readline(), f.read(), expected_pragma,
     )
@@ -103,21 +101,20 @@ def fix_encoding_pragma(f, remove=False, expected_pragma=DEFAULT_PRAGMA):
     return 1
 
 
-def _normalize_pragma(pragma):  # type: (Union[bytes, str]) -> bytes
-    if not isinstance(pragma, bytes):
-        pragma = pragma.encode('UTF-8')
-    return pragma.rstrip()
+def _normalize_pragma(pragma: str) -> bytes:
+    return pragma.encode().rstrip()
 
 
-def main(argv=None):  # type: (Optional[Sequence[str]]) -> int
+def main(argv: Optional[Sequence[str]] = None) -> int:
     parser = argparse.ArgumentParser(
         'Fixes the encoding pragma of python files',
     )
     parser.add_argument('filenames', nargs='*', help='Filenames to fix')
     parser.add_argument(
         '--pragma', default=DEFAULT_PRAGMA, type=_normalize_pragma,
-        help='The encoding pragma to use.  Default: {}'.format(
-            DEFAULT_PRAGMA.decode(),
+        help=(
+            f'The encoding pragma to use.  '
+            f'Default: {DEFAULT_PRAGMA.decode()}'
         ),
     )
     parser.add_argument(
@@ -141,9 +138,7 @@ def main(argv=None):  # type: (Optional[Sequence[str]]) -> int
             retv |= file_ret
             if file_ret:
                 print(
-                    fmt.format(
-                        pragma=args.pragma.decode(), filename=filename,
-                    ),
+                    fmt.format(pragma=args.pragma.decode(), filename=filename),
                 )
 
     return retv