Merged revisions 82732,82734,82738 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/release27-maint

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  r82732 | r.david.murray | 2010-07-09 09:16:00 -0400 (Fri, 09 Jul 2010) | 13 lines

  Merged revisions 82730 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/branches/py3k

  'merge' in the sense that this is the same fix by the same author.

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    r82730 | r.david.murray | 2010-07-09 08:23:21 -0400 (Fri, 09 Jul 2010) | 4 lines

    7846: limit fnmatch pattern cache to _MAXCACHE=100 entries.

    Patch by Andrew Clegg.
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  r82734 | r.david.murray | 2010-07-09 09:17:45 -0400 (Fri, 09 Jul 2010) | 9 lines

  Merged revisions 82731 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/branches/py3k

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    r82731 | r.david.murray | 2010-07-09 09:14:03 -0400 (Fri, 09 Jul 2010) | 2 lines

    Fix sort order mistake in Misc/ACKS.
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  r82738 | r.david.murray | 2010-07-09 09:25:56 -0400 (Fri, 09 Jul 2010) | 2 lines

  Add missing NEWS entry for 7646.
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diff --git a/Lib/fnmatch.py b/Lib/fnmatch.py
index 4c149eb..b1c37f5 100644
--- a/Lib/fnmatch.py
+++ b/Lib/fnmatch.py
@@ -15,6 +15,7 @@
 __all__ = ["filter", "fnmatch","fnmatchcase","translate"]
 
 _cache = {}
+_MAXCACHE = 100
 
 def fnmatch(name, pat):
     """Test whether FILENAME matches PATTERN.
@@ -44,6 +45,8 @@
     pat=os.path.normcase(pat)
     if not pat in _cache:
         res = translate(pat)
+        if len(_cache) >= _MAXCACHE:
+            _cache.clear()
         _cache[pat] = re.compile(res)
     match=_cache[pat].match
     if os.path is posixpath:
@@ -66,6 +69,8 @@
 
     if not pat in _cache:
         res = translate(pat)
+        if len(_cache) >= _MAXCACHE:
+            _cache.clear()
         _cache[pat] = re.compile(res)
     return _cache[pat].match(name) is not None
 
diff --git a/Lib/test/test_fnmatch.py b/Lib/test/test_fnmatch.py
index 3a55b85..015c580 100644
--- a/Lib/test/test_fnmatch.py
+++ b/Lib/test/test_fnmatch.py
@@ -3,7 +3,7 @@
 from test import test_support
 import unittest
 
-from fnmatch import fnmatch, fnmatchcase
+from fnmatch import fnmatch, fnmatchcase, _MAXCACHE, _cache
 
 
 class FnmatchTestCase(unittest.TestCase):
@@ -49,6 +49,15 @@
         check('AbC', 'abc', 0, fnmatchcase)
         check('abc', 'AbC', 0, fnmatchcase)
 
+    def test_cache_clearing(self):
+        # check that caches do not grow too large
+        # http://bugs.python.org/issue7846
+
+        # string pattern cache
+        for i in range(_MAXCACHE + 1):
+            fnmatch('foo', '?' * i)
+
+        self.assertTrue(len(_cache) <= _MAXCACHE)
 
 def test_main():
     test_support.run_unittest(FnmatchTestCase)