Added requirements.txt hook

README.md

@@ -30,6 +30,7 @@ Add this to your `.pre-commit-config.yaml`
 - `flake8` - Run flake8 on your python files
 - `name-tests-test` - Assert that files in tests/ end in _test.py
 - `pyflakes` - Run pyflakes on your python files
+- `requirements-txt-fixer` - Sorts entries in requirements.txt
 - `trailing-whitespace` - Trims trailing whitespace.
 
 ### As a standalone package

hooks.yaml

@@ -47,6 +47,12 @@
     entry: pyflakes
     language: python
     files: \.py$
+-   id: requirements-txt-fixer
+    name: Fix requirements.txt
+    description: Sorts entries in requirements.txt
+    entry: requirements-txt-fixer
+    language: python
+    files: requirements.*\.txt$
 -   id: trailing-whitespace
     name: Trim Trailing Whitespace
     description: This hook trims trailing whitespace.

pre_commit_hooks/requirements_txt_fixer.py

@@ -0,0 +1,82 @@
+from __future__ import print_function
+
+import argparse
+
+from pre_commit_hooks.util import entry
+
+
+class Requirement(object):
+
+    def __init__(self):
+        super(Requirement, self).__init__()
+        self.value = None
+        self.comments = []
+
+    def __lt__(self, requirement):
+        # \n means top of file comment, so always return True,
+        # otherwise just do a string comparison with value.
+        if self.value == b'\n':
+            return True
+        elif requirement.value == b'\n':
+            return False
+        else:
+            return self.value < requirement.value
+
+
+def fix_requirements(f):
+    requirements = []
+    before = []
+    after = []
+
+    for line in f:
+        before.append(line)
+
+        # If the most recent requirement object has a value, then it's time to
+        # start building the next requirement object.
+        if not len(requirements) or requirements[-1].value is not None:
+            requirements.append(Requirement())
+
+        requirement = requirements[-1]
+
+        # If we see a newline before any requirements, then this is a top of
+        # file comment.
+        if len(requirements) == 1 and line.strip() == b'':
+            if len(requirement.comments) and requirement.comments[0].startswith(b'#'):
+                requirement.value = b'\n'
+            else:
+                requirement.comments.append(line)
+        elif line.startswith(b'#') or line.strip() == b'':
+            requirement.comments.append(line)
+        else:
+            requirement.value = line
+
+    for requirement in sorted(requirements):
+        for comment in requirement.comments:
+            after.append(comment)
+        after.append(requirement.value)
+
+    before_string = b''.join(before)
+    after_string = b''.join(after)
+
+    if before_string == after_string:
+        return 0
+    else:
+        f.seek(0)
+        f.write(after_string)
+        f.truncate()
+        return 1
+
+
+@entry
+def fix_requirements_txt(argv):
+    parser = argparse.ArgumentParser()
+    parser.add_argument('filenames', nargs='*', help='Filenames to fix')
+    args = parser.parse_args(argv)
+
+    retv = 0
+
+    for arg in args.filenames:
+        with open(arg, 'rb+') as f:
+            retv |= fix_requirements(f)
+
+    return retv

requirements-dev.txt

@@ -3,6 +3,6 @@
 coverage
 flake8
 mock
-pylint
+pylint<1.4
 pytest
 pre-commit

setup.py

@@ -42,6 +42,7 @@ setup(
             'debug-statement-hook = pre_commit_hooks.debug_statement_hook:debug_statement_hook',
             'end-of-file-fixer = pre_commit_hooks.end_of_file_fixer:end_of_file_fixer',
             'name-tests-test = pre_commit_hooks.tests_should_end_in_test:validate_files',
+            'requirements-txt-fixer = pre_commit_hooks.requirements_txt_fixer:fix_requirements',
             'trailing-whitespace-fixer = pre_commit_hooks.trailing_whitespace_fixer:fix_trailing_whitespace',
         ],
     },

tests/requirements_txt_fixer_test.py

@@ -0,0 +1,47 @@
+import os.path
+import pytest
+
+from pre_commit_hooks.requirements_txt_fixer import fix_requirements_txt
+from pre_commit_hooks.requirements_txt_fixer import Requirement
+
+# Input, expected return value, expected output
+TESTS = (
+    (b'foo\nbar\n', 1, b'bar\nfoo\n'),
+    (b'bar\nfoo\n', 0, b'bar\nfoo\n'),
+    (b'#comment1\nfoo\n#comment2\nbar\n', 1, b'#comment2\nbar\n#comment1\nfoo\n'),
+    (b'#comment1\nbar\n#comment2\nfoo\n', 0, b'#comment1\nbar\n#comment2\nfoo\n'),
+    (b'#comment\n\nfoo\nbar\n', 1, b'#comment\n\nbar\nfoo\n'),
+    (b'#comment\n\nbar\nfoo\n', 0, b'#comment\n\nbar\nfoo\n'),
+    (b'\nfoo\nbar\n', 1, b'bar\n\nfoo\n'),
+    (b'\nbar\nfoo\n', 0, b'\nbar\nfoo\n'),
+)
+
+
+@pytest.mark.parametrize(('input', 'expected_retval', 'output'), TESTS)
+def test_integration(input, expected_retval, output, tmpdir):
+    path = os.path.join(tmpdir.strpath, 'file.txt')
+
+    with open(path, 'wb') as file_obj:
+        file_obj.write(input)
+
+    assert fix_requirements_txt([path]) == expected_retval
+    assert open(path, 'rb').read() == output
+
+
+def test_requirement_object():
+    top_of_file = Requirement()
+    top_of_file.comments.append('#foo')
+    top_of_file.value = b'\n'
+
+    requirement_foo = Requirement()
+    requirement_foo.value = b'foo'
+
+    requirement_bar = Requirement()
+    requirement_bar.value = b'bar'
+
+    # This may look redundant, but we need to test both foo.__lt__(bar) and
+    # bar.__lt__(foo)
+    assert requirement_foo > top_of_file
+    assert top_of_file < requirement_foo
+    assert requirement_foo > requirement_bar
+    assert requirement_bar < requirement_foo