From 12c9d028ed0a1803019f3796014e75c74d9de2f6 Mon Sep 17 00:00:00 2001
From: "Gregory P. Smith" <greg@krypto.org>
Date: Sat, 14 May 2011 15:15:49 -0700
Subject: [PATCH 1/3] Fixes Issue #12059: Properly handle missing hash
 functions even when the expected builtin modules are not present.

This includes a unittest for __get_builtin_constructor() in the face
of such an error.
---
 Lib/hashlib.py           | 43 +++++++++++++++++++++-------------------
 Lib/test/test_hashlib.py | 18 +++++++++++++++++
 2 files changed, 41 insertions(+), 20 deletions(-)

diff --git a/Lib/hashlib.py b/Lib/hashlib.py
index 0d7e3250d5b..0ebeed5a46e 100644
--- a/Lib/hashlib.py
+++ b/Lib/hashlib.py
@@ -64,26 +64,29 @@ __all__ = __always_supported + ('new', 'algorithms_guaranteed',
 
 
 def __get_builtin_constructor(name):
-    if name in ('SHA1', 'sha1'):
-        import _sha1
-        return _sha1.sha1
-    elif name in ('MD5', 'md5'):
-        import _md5
-        return _md5.md5
-    elif name in ('SHA256', 'sha256', 'SHA224', 'sha224'):
-        import _sha256
-        bs = name[3:]
-        if bs == '256':
-            return _sha256.sha256
-        elif bs == '224':
-            return _sha256.sha224
-    elif name in ('SHA512', 'sha512', 'SHA384', 'sha384'):
-        import _sha512
-        bs = name[3:]
-        if bs == '512':
-            return _sha512.sha512
-        elif bs == '384':
-            return _sha512.sha384
+    try:
+        if name in ('SHA1', 'sha1'):
+            import _sha1
+            return _sha1.sha1
+        elif name in ('MD5', 'md5'):
+            import _md5
+            return _md5.md5
+        elif name in ('SHA256', 'sha256', 'SHA224', 'sha224'):
+            import _sha256
+            bs = name[3:]
+            if bs == '256':
+                return _sha256.sha256
+            elif bs == '224':
+                return _sha256.sha224
+        elif name in ('SHA512', 'sha512', 'SHA384', 'sha384'):
+            import _sha512
+            bs = name[3:]
+            if bs == '512':
+                return _sha512.sha512
+            elif bs == '384':
+                return _sha512.sha384
+    except ImportError:
+         pass  # no extension module, this hash is unsupported.
 
     raise ValueError('unsupported hash type %s' % name)
 
diff --git a/Lib/test/test_hashlib.py b/Lib/test/test_hashlib.py
index fe316fdd39a..17d752b893e 100644
--- a/Lib/test/test_hashlib.py
+++ b/Lib/test/test_hashlib.py
@@ -118,6 +118,24 @@ class HashLibTestCase(unittest.TestCase):
         else:
             self.assertTrue(0 == "hashlib didn't reject bogus hash name")
 
+    def test_get_builtin_constructor(self):
+        get_builtin_constructor = hashlib.__dict__[
+                '__get_builtin_constructor']
+        self.assertRaises(ValueError, get_builtin_constructor, 'test')
+        try:
+            import _md5
+        except ImportError:
+            pass
+        # This forces an ImportError for "import _md5" statements
+        sys.modules['_md5'] = None
+        try:
+            self.assertRaises(ValueError, get_builtin_constructor, 'md5')
+        finally:
+            if '_md5' in locals():
+                sys.modules['_md5'] = _md5
+            else:
+                del sys.modules['_md5']
+
     def test_hexdigest(self):
         for name in self.supported_hash_names:
             h = hashlib.new(name)

From a3221f82099d1b000387bf2d75e906ccd6801262 Mon Sep 17 00:00:00 2001
From: "Gregory P. Smith" <greg@krypto.org>
Date: Sat, 14 May 2011 15:35:19 -0700
Subject: [PATCH 2/3] fix whitespace

---
 Lib/hashlib.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/hashlib.py b/Lib/hashlib.py
index 0ebeed5a46e..91080955ddd 100644
--- a/Lib/hashlib.py
+++ b/Lib/hashlib.py
@@ -86,7 +86,7 @@ def __get_builtin_constructor(name):
             elif bs == '384':
                 return _sha512.sha384
     except ImportError:
-         pass  # no extension module, this hash is unsupported.
+        pass  # no extension module, this hash is unsupported.
 
     raise ValueError('unsupported hash type %s' % name)
 

From 1161a9ca4059ab34f637574e7498ba79ecd6efea Mon Sep 17 00:00:00 2001
From: Nadeem Vawda <nadeem.vawda@gmail.com>
Date: Sun, 15 May 2011 00:48:24 +0200
Subject: [PATCH 3/3] Fix copy-paste mistake in new zlib test.

---
 Lib/test/test_zlib.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
index 0909aa17b21..599ce24f41d 100644
--- a/Lib/test/test_zlib.py
+++ b/Lib/test/test_zlib.py
@@ -528,9 +528,11 @@ class CompressObjectTestCase(BaseCompressTestCase, unittest.TestCase):
         if size < _4G + 100:
             self.skipTest("not enough free memory, need at least 4 GB")
         data = b'x' * size
+        c = zlib.compressobj(1)
+        d = zlib.decompressobj()
         try:
-            self.assertRaises(OverflowError, zlib.compress, data, 1)
-            self.assertRaises(OverflowError, zlib.decompress, data)
+            self.assertRaises(OverflowError, c.compress, data)
+            self.assertRaises(OverflowError, d.decompress, data)
         finally:
             data = None