.

bigfile/_file_zodb.pyx

@@ -58,8 +58,8 @@ from wendelin.lib.zodb import zconn_at
 # _ZBigFile is base class for ZBigFile that provides BigFile-line base.
 #
 # The other base line is from Persistent. It is not possible to inherit from
-# both Persistent and BigFile at the same time since both types are C types and
-# their layouts conflict.
+# both Persistent and BigFile at the same time since both are C types and their
+# layouts conflict.
 #
 # _ZBigFile:
 #
@@ -141,8 +141,9 @@ cdef wcfs.PyConn pywconnOf(zconn):
 
 
 # ZSync keeps wconn in sync with zconn.
-# XXX -> make generic and usefor _ZBigFileH too?
-# XXX naming?
+# XXX -> make generic and use for _ZBigFileH too?
+#        -> y: ZSync base + ZSyncWConn, ZSyncBigFileH
+# XXX naming? -> ZKeepInSync ?
 class ZSync:
     # .zconn
     # .wconn

lib/tests/test_zodb.py

@@ -305,6 +305,46 @@ def test_zconn_at():
     assert zconn_at(conn_at0) == at0
 
 
+# verify that ZODB.Connection.onResyncCallback works
+@func
+def test_zodb_onresync():
+    stor = testdb.getZODBStorage()
+    defer(stor.close)
+    db  = DB(stor)
+
+    class T:
+        def __init__(t):
+            t.nresync = 0
+        def on_connection_resync(t):
+            t.nresync += 1
+
+    t = T()
+
+    conn = db.open()
+    conn.onResyncCallback(t)
+    assert t.nresync == 0
+
+    # abort makes conn to enter new transaction
+    transaction.abort()
+    assert t.nresync == 1
+
+    # close/reopen -> new transaction
+    conn.close()
+    assert t.nresync == 1
+    conn_ = db.open()
+    assert conn_ is conn
+    assert t.nresync == 2
+
+    # commit -> new transaction
+    root = conn.root()
+    root['r'] = 1
+    assert t.nresync == 2
+    transaction.commit()
+    assert t.nresync == 3
+
+    conn.close()
+
+
 # ---- misc ----
 
 # zsync syncs ZODB storage.