accept datetime instances as dates

There's no easy way to re-create a commit (i.e. for rewriting purposes), because dates must be formatted as strings, passed, then parsed back.

This patch allows parse_date() to accept datetime instances, such as those produced by from_timestamp() above.

Author: mildsunrise

Diff for: git/objects/util.py

@@ -135,6 +135,7 @@ def parse_date(string_date):
     """
     Parse the given date as one of the following
 
+        * aware datetime instance
         * Git internal format: timestamp offset
         * RFC 2822: Thu, 07 Apr 2005 22:13:13 +0200.
         * ISO 8601 2005-04-07T22:13:13
@@ -144,6 +145,10 @@ def parse_date(string_date):
     :raise ValueError: If the format could not be understood
     :note: Date can also be YYYY.MM.DD, MM/DD/YYYY and DD.MM.YYYY.
     """
+    if isinstance(string_date, datetime) and string_date.tzinfo:
+        offset = -int(string_date.utcoffset().total_seconds())
+        return int(string_date.astimezone(utc).timestamp()), offset
+
     # git time
     try:
         if string_date.count(' ') == 1 and string_date.rfind(':') == -1:

Diff for: test/test_util.py

@@ -174,6 +174,10 @@ def test_user_id(self):
         self.assertIn('@', get_user_id())
 
     def test_parse_date(self):
+        # parse_date(from_timestamp()) must return the tuple unchanged
+        for timestamp, offset in (1522827734, -7200), (1522827734, 0), (1522827734, +3600):
+            self.assertEqual(parse_date(from_timestamp(timestamp, offset)), (timestamp, offset))
+
         # test all supported formats
         def assert_rval(rval, veri_time, offset=0):
             self.assertEqual(len(rval), 2)
@@ -200,6 +204,7 @@ def assert_rval(rval, veri_time, offset=0):
         # END for each date type
 
         # and failure
+        self.assertRaises(ValueError, parse_date, datetime.now())  # non-aware datetime
         self.assertRaises(ValueError, parse_date, 'invalid format')
         self.assertRaises(ValueError, parse_date, '123456789 -02000')
         self.assertRaises(ValueError, parse_date, ' 123456789 -0200')