Adding detect-raw-datetime-manipulation option

.pre-commit-hooks.yaml

@@ -105,6 +105,12 @@
     entry: detect-private-key
     language: python
     types: [text]
+-   id: detect-datetime-raw-manipulation
+    name: Detect Raw datetime manipulation
+    description: Detects the raw manipulation of datetime.
+    entry: detect-datetime-raw-manipulation
+    language: python
+    types: [text]
 -   id: double-quote-string-fixer
     name: Fix double quoted strings
     description: This hook replaces double quoted strings with single quoted strings

README.md

@@ -64,6 +64,7 @@ Add this to your `.pre-commit-config.yaml`
   - `--allow-missing-credentials` - Allow hook to pass when no credentials are
     detected.
 - `detect-private-key` - Checks for the existence of private keys.
+- `detect-datetime-raw-manipulation` - Check for raw manipulation of datetime.
 - `double-quote-string-fixer` - This hook replaces double quoted strings
   with single quoted strings.
 - `end-of-file-fixer` - Makes sure files end in a newline and only a newline.

pre_commit_hooks/detect_datetime_raw_manipulation.py

@@ -0,0 +1,43 @@
+from __future__ import print_function
+from __future__ import unicode_literals
+
+import argparse
+import re
+import sys
+
+DT_MANIPULATION_RE = re.compile(
+    r'[+-]=?\s?datetime.timedelta\(|[+-]=?\s?timedelta\(|.replace\(.*tzinfo=|datetime\(.*tzinfo=',
+)
+
+
+def _check_file(filename):
+    return_value = 0
+    with open(filename, 'r') as f:
+        for i, line in enumerate(f, 1):
+            if DT_MANIPULATION_RE.search(line):
+                if line.strip().endswith('  # safe_dt_op') or line.strip().startswith('#'):
+                    continue
+
+                sys.stdout.write('{}:{}: {}'.format(filename, i, line))
+                sys.stdout.flush()
+
+                return_value += 1
+
+    return return_value
+
+
+def main(argv=None):
+    parser = argparse.ArgumentParser()
+    parser.add_argument('filenames', nargs='*')
+    args = parser.parse_args(argv)
+
+    return_value = 0
+    for filename in args.filenames:
+        result = _check_file(filename)
+        return_value |= 1 if result > 0 else 0
+
+    return return_value
+
+
+if __name__ == '__main__':
+    exit(main())

setup.py

@@ -6,7 +6,7 @@ setup(
     name='pre_commit_hooks',
     description='Some out-of-the-box hooks for pre-commit.',
     url='https://github.com/pre-commit/pre-commit-hooks',
-    version='2.0.0',
+    version='2.1.0',
 
     author='Anthony Sottile',
     author_email='asottile@umich.edu',
@@ -47,6 +47,8 @@ setup(
             'debug-statement-hook = pre_commit_hooks.debug_statement_hook:main',
             'detect-aws-credentials = pre_commit_hooks.detect_aws_credentials:main',
             'detect-private-key = pre_commit_hooks.detect_private_key:detect_private_key',
+            'detect-datetime-raw-manipulation = '
+            'pre_commit_hooks.detect_datetime_raw_manipulation:detect_datetime_raw_manipulation',
             'double-quote-string-fixer = pre_commit_hooks.string_fixer:main',
             'end-of-file-fixer = pre_commit_hooks.end_of_file_fixer:end_of_file_fixer',
             'file-contents-sorter = pre_commit_hooks.file_contents_sorter:main',

testing/resources/detect_datetime_raw_manipulation/raw_timedelta_usage__clean.py

@@ -0,0 +1,27 @@
+import datetime
+from datetime import timedelta
+
+
+def dummy_func(inp):
+    print(inp)
+
+
+def move_time_forward():
+    now = datetime.datetime.now()
+
+    # Check commented out lines
+    # now += timedelta(days=1)
+    # now += datetime.timedelta(weeks=1)
+    #
+    # now -= timedelta(weeks=1)
+    # now -= timedelta(weeks=2)
+    #
+    # now = now.replace(hour=2)
+    # now = now.replace(tzinfo=None)
+    # now = now.replace(hour=1, tzinfo=pytz.utc)
+
+    # Test regular usage of timedelta & datetime
+    dummy_func(timedelta(days=1))
+    dummy_func(datetime.datetime(2018, 10, 11, 2, 3, 4, 450000))
+
+    print(now)

testing/resources/detect_datetime_raw_manipulation/raw_timedelta_usage__flag.py

@@ -0,0 +1,37 @@
+import datetime
+from datetime import timedelta
+
+import pytz
+
+
+def move_time_forward():
+    now = datetime.datetime.now()
+    timezone = pytz.utc
+
+    # 1
+    now = datetime.datetime(now.year, now.month, now.day, hour=8, minute=0, tzinfo=timezone)
+
+    # 2
+    now += timedelta(days=1)
+    # 3
+    now += datetime.timedelta(weeks=1)
+    # 4
+    now = now + timedelta(seconds=1)
+
+    # 5
+    now -= datetime.timedelta(weeks=1)
+    # 6
+    now -= timedelta(weeks=2)
+    # 7
+    now = now - timedelta(seconds=1)
+
+    now = now.replace(hour=2)
+    # 8
+    now = now.replace(tzinfo=None)
+    # 9
+    now = now.replace(hour=1, tzinfo=pytz.utc)
+
+    # 10
+    now = datetime.datetime(2018, 10, 11, 2, 3, 4, 450000, tzinfo=pytz.utc)
+
+    print(now)

testing/resources/detect_datetime_raw_manipulation/raw_timedelta_usage__ignore.py

@@ -0,0 +1,20 @@
+import datetime
+from datetime import timedelta
+
+import pytz
+
+
+def move_time_forward():
+    now = datetime.datetime.now()
+
+    now += timedelta(days=1)  # safe_dt_op
+    now += datetime.timedelta(weeks=1)  # safe_dt_op
+
+    now -= timedelta(weeks=1)  # safe_dt_op
+    now -= timedelta(weeks=2)  # safe_dt_op
+
+    now = now.replace(hour=2)
+    now = now.replace(tzinfo=None)  # safe_dt_op
+    now = now.replace(hour=1, tzinfo=pytz.utc)  # safe_dt_op
+
+    print(now)

tests/detect_raw_datetime_manipulation_test.py

@@ -0,0 +1,24 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+from pre_commit_hooks.detect_datetime_raw_manipulation import _check_file
+from pre_commit_hooks.detect_datetime_raw_manipulation import main
+from testing.util import get_resource_path
+
+
+def test_flagged_file():
+    rc = main([get_resource_path('detect_datetime_raw_manipulation/raw_timedelta_usage__flag.py')])
+    assert rc == 1
+
+    result = _check_file(get_resource_path('detect_datetime_raw_manipulation/raw_timedelta_usage__flag.py'))
+    assert result == 10
+
+
+def test_flagged_ignore():
+    rc = main([get_resource_path('detect_datetime_raw_manipulation/raw_timedelta_usage__ignore.py')])
+    assert rc == 0
+
+
+def test_flagged_clean():
+    rc = main([get_resource_path('detect_datetime_raw_manipulation/raw_timedelta_usage__clean.py')])
+    assert rc == 0