[Python-checkins] r76464 - in python/trunk: Lib/difflib.py Lib/test/test_difflib.py Misc/NEWS

[senthil.kumaran]

Author: senthil.kumaran
Date: Mon Nov 23 19:41:31 2009
New Revision: 76464

Log:
Fix for issue1488943 - difflib.Differ() doesn't always add hints for tab
characters.



Modified:
   python/trunk/Lib/difflib.py
   python/trunk/Lib/test/test_difflib.py
   python/trunk/Misc/NEWS

Modified: python/trunk/Lib/difflib.py
==============================================================================
--- python/trunk/Lib/difflib.py	(original)
+++ python/trunk/Lib/difflib.py	Mon Nov 23 19:41:31 2009
@@ -1061,20 +1061,21 @@
         Example:
 
         >>> d = Differ()
-        >>> results = d._qformat('\tabcDefghiJkl\n', '\t\tabcdefGhijkl\n',
-        ...                      '  ^ ^  ^      ', '+  ^ ^  ^      ')
+        >>> results = d._qformat('\tabcDefghiJkl\n', '\tabcdefGhijkl\n',
+        ...                      '  ^ ^  ^      ', '  ^ ^  ^      ')
         >>> for line in results: print repr(line)
         ...
         '- \tabcDefghiJkl\n'
         '? \t ^ ^  ^\n'
-        '+ \t\tabcdefGhijkl\n'
-        '? \t  ^ ^  ^\n'
+        '+ \tabcdefGhijkl\n'
+        '? \t ^ ^  ^\n'
         """
 
         # Can hurt, but will probably help most of the time.
         common = min(_count_leading(aline, "\t"),
                      _count_leading(bline, "\t"))
         common = min(common, _count_leading(atags[:common], " "))
+        common = min(common, _count_leading(btags[:common], " "))
         atags = atags[common:].rstrip()
         btags = btags[common:].rstrip()
 

Modified: python/trunk/Lib/test/test_difflib.py
==============================================================================
--- python/trunk/Lib/test/test_difflib.py	(original)
+++ python/trunk/Lib/test/test_difflib.py	Mon Nov 23 19:41:31 2009
@@ -20,6 +20,14 @@
         diff_gen = difflib.unified_diff([], [])
         self.assertRaises(StopIteration, diff_gen.next)
 
+    def test_added_tab_hint(self):
+        # Check fix for bug #1488943
+        diff = list(difflib.Differ().compare(["\tI am a buggy"],["\t\tI am a bug"]))
+        self.assertEqual("- \tI am a buggy", diff[0])
+        self.assertEqual("?            --\n", diff[1])
+        self.assertEqual("+ \t\tI am a bug", diff[2])
+        self.assertEqual("? +\n", diff[3])
+
 patch914575_from1 = """
    1. Beautiful is beTTer than ugly.
    2. Explicit is better than implicit.

Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS	(original)
+++ python/trunk/Misc/NEWS	Mon Nov 23 19:41:31 2009
@@ -476,6 +476,8 @@
 Library
 -------
 
+- Issue #1488943: difflib.Differ() doesn't always add hints for tab characters
+
 - Issue #6123: tarfile now opens empty archives correctly and consistently
   raises ReadError on empty files.