Merge rev 37790 from 3.4 branch.

More on collector 1847 (ZEO cache tracing).

simul.py hit NameErrors when startup cache verification
found data in the cache to invalidate.

The cache's loadBefore() implementation called _trace()
incorrectly, passing the tid where the version argument
belonged.

src/ZEO/cache.py

@@ -203,7 +203,7 @@ class ClientCache(object):
     def loadBefore(self, oid, tid):
         L = self.noncurrent.get(oid)
         if L is None:
-            self._trace(0x24, oid, tid)
+            self._trace(0x24, oid, "", tid)
             return None
         # A pair with None as the second element is less than any pair with
         # the same first tid.  Dubious:  this relies on that None is less
@@ -214,15 +214,15 @@ class ClientCache(object):
         # Therefore the largest start_tid < tid must be at L[i-1].  If i is 0,
         # there is no start_tid < tid:  we don't have any data old enougn.
         if i == 0:
-            self._trace(0x24, oid, tid)
+            self._trace(0x24, oid, "", tid)
             return
         lo, hi = L[i-1]
         assert lo < tid
         if tid > hi:    # we don't have any data in the right range
-            self._trace(0x24, oid, tid)
+            self._trace(0x24, oid, "", tid)
             return None
         o = self.fc.access((oid, lo))
-        self._trace(0x26, oid, tid)
+        self._trace(0x26, oid, "", tid)
         return o.data, o.start_tid, o.end_tid
 
     ##

src/ZEO/simul.py

@@ -397,7 +397,7 @@ class CircularCacheSimulation(Simulation):
         if tid == z64:
             # This is part of startup cache verification:  forget everything
             # about this oid.
-            self._remove_noncurrent_revisions(oid, version)
+            self._remove_noncurrent_revisions(oid)
 
         cur_tid = self.current.get(oid)
         if cur_tid is None:
@@ -410,7 +410,7 @@ class CircularCacheSimulation(Simulation):
         del self.current[oid]
         if tid == z64:
             # Startup cache verification:  forget this oid entirely.
-            self._remove(oid, current_tid)
+            self._remove(oid, cur_tid)
             return
 
         # Our current data becomes non-current data.