Adds remove-tabs hook

Inpired by initial work done by Lucas-C:
https://github.com/Lucas-C/pre-commit-hooks

.pre-commit-hooks.yaml

@@ -173,6 +173,12 @@
     entry: requirements-txt-fixer
     language: python
     files: requirements.*\.txt$
+-   id: remove-tabs
+    name: Check docstring is first
+    description: Remove tabs from files and replaces them with spaces.
+    entry: remove-tabs
+    language: python
+    types: [text]
 -   id: sort-simple-yaml
     name: Sort simple YAML files
     language: python

README.md

@@ -93,6 +93,7 @@ Add this to your `.pre-commit-config.yaml`
     - `--no-sort-keys` - when autofixing, retain the original key ordering (instead of sorting the keys)
     - `--top-keys comma,separated,keys` - Keys to keep at the top of mappings.
 - `requirements-txt-fixer` - Sorts entries in requirements.txt and removes incorrect entry for `pkg-resources==0.0.0`
+- `remove-tabs` - Replace tabs by whitespaces before committing
 - `sort-simple-yaml` - Sorts simple YAML files which consist only of top-level keys, preserving comments and blocks.
 - `trailing-whitespace` - Trims trailing whitespace.
     - To preserve Markdown [hard linebreaks](https://github.github.com/gfm/#hard-line-break)

pre_commit_hooks/remove_tabs.py

@@ -0,0 +1,53 @@
+from __future__ import print_function
+
+import argparse
+import sys
+from typing import Any
+
+
+def contains_tabs(filename):  # type: (str) -> bool
+    with open(filename, mode='rb') as file_checked:
+        return b'\t' in file_checked.read()
+
+
+def removes_tabs_in_file(filename, whitespaces_count):
+    # type: (str, int) -> None
+    with open(filename, mode='rb') as file_processed:
+        lines = file_processed.readlines()
+    lines = [line.replace(b'\t', b' ' * whitespaces_count) for line in lines]
+    with open(filename, mode='wb') as file_processed:
+        for line in lines:
+            file_processed.write(line)
+
+
+def main(argv=None):  # type: (Any) -> int
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        '--whitespaces-count', type=int, required=True,
+        help='number of whitespaces to substitute tabs with',
+    )
+    parser.add_argument('filenames', nargs='*', help='Filenames to fix')
+
+    args = parser.parse_args(argv)
+
+    return_code = 0
+    for filename in args.filenames:
+        if contains_tabs(filename):
+            print('Substituting tabs in: {} by {} whitespaces'.format(
+                filename, args.whitespaces_count,
+            ))
+            removes_tabs_in_file(filename, args.whitespaces_count)
+            return_code = 1
+
+    if return_code:
+        print('')
+        print('Tabs have been successfully removed. Now aborting the commit.')
+        print(
+            'You can check the changes made. Then simply '
+            '"git add --update ." and re-commit',
+        )
+    return return_code
+
+
+if __name__ == '__main__':
+    sys.exit(main())

tests/remove_tabs_test.py

@@ -0,0 +1,31 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import pytest
+
+from pre_commit_hooks.remove_tabs import main as remove_tabs
+
+
+@pytest.mark.parametrize(
+    ('input_s', 'expected'),
+    (
+        ('foo \t\nbar', 'foo     \nbar'),
+        ('bar\n\tbaz\n', 'bar\n    baz\n'),
+    ),
+)
+def test_remove_tabs(input_s, expected, tmpdir):
+    path = tmpdir.join('file.txt')
+    path.write(input_s)
+    assert remove_tabs(('--whitespaces-count=4', path.strpath)) == 1
+    assert path.read() == expected
+
+
+@pytest.mark.parametrize(('arg'), ('', '--', 'a.b', 'a/b'))
+def test_badopt(arg):
+    with pytest.raises(SystemExit) as excinfo:
+        remove_tabs(['--whitespaces-count', arg])
+    assert excinfo.value.code == 2
+
+
+def test_nothing_to_fix():
+    assert remove_tabs(['--whitespaces-count=4', __file__]) == 0