From fabefc3c5b9e174e4eef2cb351a6ed8c81d721b0 Mon Sep 17 00:00:00 2001 From: Raymond Hettinger Date: Sat, 21 Jun 2014 11:57:36 -0700 Subject: Issue 21635: Fix caching in difflib.SequenceMatcher.get_matching_blocks(). --- Lib/difflib.py | 4 ++-- Lib/test/test_difflib.py | 9 +++++++++ Misc/NEWS | 4 ++++ 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/Lib/difflib.py b/Lib/difflib.py index 38dfef4..7eb42a9 100644 --- a/Lib/difflib.py +++ b/Lib/difflib.py @@ -511,8 +511,8 @@ class SequenceMatcher: non_adjacent.append((i1, j1, k1)) non_adjacent.append( (la, lb, 0) ) - self.matching_blocks = non_adjacent - return map(Match._make, self.matching_blocks) + self.matching_blocks = list(map(Match._make, non_adjacent)) + return self.matching_blocks def get_opcodes(self): """Return list of 5-tuples describing how to turn a into b. diff --git a/Lib/test/test_difflib.py b/Lib/test/test_difflib.py index 325449a..0ba8f0e 100644 --- a/Lib/test/test_difflib.py +++ b/Lib/test/test_difflib.py @@ -76,6 +76,15 @@ class TestSFbugs(unittest.TestCase): diff_gen = difflib.unified_diff([], []) self.assertRaises(StopIteration, next, diff_gen) + def test_matching_blocks_cache(self): + # Issue #21635 + s = difflib.SequenceMatcher(None, "abxcd", "abcd") + first = s.get_matching_blocks() + second = s.get_matching_blocks() + self.assertEqual(second[0].size, 2) + self.assertEqual(second[1].size, 2) + self.assertEqual(second[2].size, 0) + 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"])) diff --git a/Misc/NEWS b/Misc/NEWS index b8e7219..a94d073 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -29,6 +29,10 @@ Library - Issue #21491: socketserver: Fix a race condition in child processes reaping. +- Issue #21635: The difflib SequenceMatcher.get_matching_blocks() method + cache didn't match the actual result. The former was a list of tuples + and the latter was a list of named tuples. + - Issue #21722: The distutils "upload" command now exits with a non-zero return code when uploading fails. Patch by Martin Dengler. -- cgit v0.12