Fixed a serious bug that caused cache failures when run

with Python optimization turned on.

NEWS.txt

+
+Whats new in ZODB 3.8.6 (2010-??-??)
+====================================
+
+Bug Fixed:
+
+- Fixed a serious bug that caused cache failures when run
+  with Python optimization turned on.
+
+  https://bugs.launchpad.net/zodb/+bug/544305
+
 Whats new in ZODB 3.8.5 (2009-12-16)
 ====================================
 

src/ZEO/cache.py

@@ -416,7 +416,8 @@ class ClientCache(object):
             return None
         self.f.seek(ofs)
         read = self.f.read
-        assert read(1) == 'a', (ofs, self.f.tell(), oid)
+        status = read(1)
+        assert status == 'a', (ofs, self.f.tell(), oid)
         size, saved_oid, tid, end_tid, lver, ldata = unpack(
             ">I8s8s8shI", read(34))
         assert saved_oid == oid, (ofs, self.f.tell(), oid, saved_oid)
@@ -456,7 +457,8 @@ class ClientCache(object):
 
         self.f.seek(ofs)
         read = self.f.read
-        assert read(1) == 'a', (ofs, self.f.tell(), oid, before_tid)
+        status = read(1)
+        assert status == 'a', (ofs, self.f.tell(), oid, before_tid)
         size, saved_oid, saved_tid, end_tid, lver, ldata = unpack(
             ">I8s8s8shI", read(34))
         assert saved_oid == oid, (ofs, self.f.tell(), oid, saved_oid)
@@ -490,7 +492,8 @@ class ClientCache(object):
             return None
         self.f.seek(ofs)
         read = self.f.read
-        assert self.f.read(1) == 'a', (ofs, self.f.tell(), oid)
+        status = read(1)
+        assert status == 'a', (ofs, self.f.tell(), oid)
         size, saved_oid, saved_tid, end_tid, lver, ldata = unpack(
             ">I8s8s8shI", read(34))
         assert saved_oid == oid, (ofs, self.f.tell(), oid, saved_oid)
@@ -525,7 +528,8 @@ class ClientCache(object):
             if ofs:
                 seek(ofs)
                 read = self.f.read
-                assert read(1) == 'a', (ofs, self.f.tell(), oid)
+                status = read(1)
+                assert status == 'a', (ofs, self.f.tell(), oid)
                 size, saved_oid, saved_tid, end_tid = unpack(
                     ">I8s8s8s", read(28))
                 assert saved_oid == oid, (ofs, self.f.tell(), oid, saved_oid)
@@ -644,7 +648,8 @@ class ClientCache(object):
 
         self.f.seek(ofs)
         read = self.f.read
-        assert read(1) == 'a', (ofs, self.f.tell(), oid)
+        status = read(1)
+        assert status == 'a', (ofs, self.f.tell(), oid)
         size, saved_oid, saved_tid, end_tid, lver = unpack(
             ">I8s8s8sh", read(30))
         assert saved_oid == oid, (ofs, self.f.tell(), oid, saved_oid)
@@ -680,7 +685,8 @@ class ClientCache(object):
             self._lock.acquire()
             try:
                 seek(ofs)
-                assert read(1) == 'a', (ofs, self.f.tell(), oid)
+                status = read(1)
+                assert status == 'a', (ofs, self.f.tell(), oid)
                 size, saved_oid, tid, end_tid, lver = unpack(
                     ">I8s8s8sh", read(30))
                 assert saved_oid == oid, (ofs, self.f.tell(), oid, saved_oid)