Forward port from ZODB 3.2.

Collector 1581:  fspack can blow up when .fs is corrupted

Repaired three places where fspack referenced an undefined global while
*trying* to raise CorruptedError.  Added new checkCorruptionInPack()
test to verify the correct exception gets raised.

NEWS.txt

@@ -28,6 +28,15 @@ trying to determine the object's class path.  This was confusing.  The code
 has been changed to obtain the class path from the object's pickle, without
 trying to import application modules or classes.
 
+FileStorage
+-----------
+
+Collector 1581:  When an attempt to pack a corrupted ``Data.fs`` file was
+made, it was possible for the pack routine to die with a reference to an
+undefined global while it was trying to raise ``CorruptedError``.  It
+raises ``CorruptedError``, as it always intended, in these cases now.
+
+
 Install
 -------
 

src/ZODB/FileStorage/fspack.py

@@ -264,7 +264,7 @@ class GC(FileStorageFormatter):
             if tlen != th.tlen:
                 self.fail(pos, "redundant transaction length does not "
                           "match initial transaction length: %d != %d",
-                          u64(s), th.tlen)
+                          tlen, th.tlen)
             pos += 8
 
         self.packpos = pos
@@ -359,7 +359,7 @@ class GC(FileStorageFormatter):
             if tlen != th.tlen:
                 self.fail(pos, "redundant transaction length does not "
                           "match initial transaction length: %d != %d",
-                          u64(s), th.tlen)
+                          tlen, th.tlen)
             pos += 8
 
         for pos in extra_roots:
@@ -553,7 +553,7 @@ class FileStoragePacker(FileStorageFormatter):
             if tlen != th.tlen:
                 self.fail(pos, "redundant transaction length does not "
                           "match initial transaction length: %d != %d",
-                          u64(s), th.tlen)
+                          tlen, th.tlen)
             pos += 8
 
         return pos, new_pos

src/ZODB/tests/testFileStorage.py

@@ -167,6 +167,55 @@ class FileStorageTests(
 
         self.failUnless(self._storage._records_before_save > 20)
 
+    def checkCorruptionInPack(self):
+        # This sets up a corrupt .fs file, with a redundant transaction
+        # length mismatch.  The implementation of pack in many releases of
+        # ZODB blew up if the .fs file had such damage:  it detected the
+        # damage, but the code to raise CorruptedError referenced an undefined
+        # global.
+        import time
+
+        from ZODB.DB import DB
+        from ZODB.utils import U64, p64
+        from ZODB.FileStorage.format import CorruptedError
+
+        db = DB(self._storage)
+        conn = db.open()
+        conn.root()['xyz'] = 1
+        get_transaction().commit()
+
+        # Ensure it's all on disk.
+        db.close()
+        self._storage.close()
+
+        # Reopen before damaging.
+        self.open()
+
+        # Open .fs directly, and damage content.
+        f = open('FileStorageTests.fs', 'r+b')
+        f.seek(0, 2)
+        pos2 = f.tell() - 8
+        f.seek(pos2)
+        tlen2 = U64(f.read(8))  # length-8 of the last transaction
+        pos1 = pos2 - tlen2 + 8 # skip over the tid at the start
+        f.seek(pos1)
+        tlen1 = U64(f.read(8))  # should be redundant length-8
+        self.assertEqual(tlen1, tlen2)  # verify that it is redundant
+
+        # Now damage the second copy.
+        f.seek(pos2)
+        f.write(p64(tlen2 - 1))
+        f.close()
+
+        # Try to pack.  This used to yield
+        #     NameError: global name 's' is not defined
+        try:
+            self._storage.pack(time.time(), None)
+        except CorruptedError, detail:
+            self.assert_("redundant transaction length does not match "
+                         "initial transaction length" in str(detail))
+        else:
+            self.fail("expected CorruptedError")
 
 class FileStorageRecoveryTest(
     StorageTestBase.StorageTestBase,