[issue11277] Crash with mmap and sparse files on Mac OS X

[Steffen Daode Nurpmeso]

Steffen Daode Nurpmeso <sdaoden at googlemail.com> added the comment:

On Mon,  2 May 2011 01:22:41 +0200, STINNER Victor <report at bugs.python.org> wrote:
> @sdaoden: Can you try on Python 2.7?

@haypo: Python 2.7 is absolute horror.
But i tried and produced a (terrible - i don't know the test
framework and that test_support stuff seems to have been changed
a lot since 2.7) 2 gigabyte+ big buffer test for 2.7.
(Of course: even though Python uses int, ZLib uses uInt.)
It took some time because i fell over #1202 from 2007 unprepared.

The (nasty) test works quite well on Apple, which is not such
a big surprise, because Apple's OS X is especially designed for
artists which need to work on large files, like video+ cutters,
sound designers with sample databases etc., so i would be
terribly disappointed if that wouldn't work!  Apple even
propagandize OS X for, and makes money with that very application
task - i really couldn't understand your doubts here.

----------
Added file: http://bugs.python.org/file21855/11277-27.1.diff

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue11277>
_______________________________________
-------------- next part --------------
diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
--- a/Lib/test/test_zlib.py
+++ b/Lib/test/test_zlib.py
@@ -1,10 +1,16 @@
 import unittest
-from test import test_support
+from test.test_support import TESTFN, run_unittest, import_module, unlink, requires
+from test.test_support import precisionbigmemtest, _1G, _2G
 import binascii
 import random
-from test.test_support import precisionbigmemtest, _1G
+import sys
 
-zlib = test_support.import_module('zlib')
+try:
+    import mmap
+except ImportError:
+    mmap = None
+
+zlib = import_module('zlib')
 
 
 class ChecksumTestCase(unittest.TestCase):
@@ -66,6 +72,32 @@
                          zlib.crc32('spam',  (2**31)))
 
 
+# Issue #10276 - check that inputs >=4GB are handled correctly.
+# Backport to 2.7 due to Issue #11277: why not verify INT32_MAX on 2.7?
+# Also take care of Issue #1202 here
+class ChecksumBigBufferTestCase(unittest.TestCase):
+    @unittest.skipUnless(mmap, "mmap() is not available.")
+    def test_big_buffer(self):
+        if sys.platform[:3] == 'win' or sys.platform == 'darwin':
+            requires('largefile',
+                'test requires %s bytes and a long time to run' % str(_2G+2))
+        try:
+            with open(TESTFN, "wb+") as f:
+                f.seek(_2G-2)
+                f.write("asdf")
+                f.flush()
+                try:
+                    m = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
+                    self.assertEqual(zlib.crc32(m), -2072986226)
+                    self.assertEqual(zlib.adler32(m), -2072641121)
+                finally:
+                    m.close()
+        except (IOError, OverflowError):
+            raise unittest.SkipTest("filesystem doesn't have largefile support")
+        finally:
+            unlink(TESTFN)
+
+
 class ExceptionTestCase(unittest.TestCase):
     # make sure we generate some expected errors
     def test_badlevel(self):
@@ -546,8 +578,9 @@
 
 
 def test_main():
-    test_support.run_unittest(
+    run_unittest(
         ChecksumTestCase,
+        ChecksumBigBufferTestCase,
         ExceptionTestCase,
         CompressTestCase,
         CompressObjectTestCase