.

bigfile/_file_zodb.pyx

@@ -57,6 +57,7 @@ from cpython cimport PyCapsule_New
 from ZODB.Connection import Connection as ZConnection
 from ZODB.utils import u64
 from wendelin.lib.zodb import zconn_at
+import weakref
 
 
 # _ZBigFile is base class for ZBigFile that provides BigFile-line base.
@@ -155,18 +156,18 @@ cdef wcfs.PyConn pywconnOf(zconn):
 
 
 # ZSync keeps wconn in sync with zconn.
-# XXX -> make generic and use for _ZBigFileH too?
-#        -> y: ZSync base + ZSyncWConn, ZSyncBigFileH
-# XXX naming? -> ZKeepInSync ?
+#
+# wconn will be closed once zconn is destroyed (not closed, which returns it
+# back into DB pool).
 class ZSync:
-    # .zconn
-    # .wconn
+    # .zconn_ref    weakref[zodb.Connection]
+    # .wconn        (py) wcfs.Connection
 
     def __init__(zsync, zconn, wconn):
         #print('ZSync %r %r' % (zconn, wconn))
         assert zconn.open
-        zsync.zconn = zconn     # XXX -> weakref
-        zsync.wconn = wconn
+        zsync.wconn     = wconn
+        zsync.zconn_ref = weakref.ref(zconn, zsync.on_zconn_dealloc)
 
         # NOTE zconn.onOpenCallback is not enough: zconn.at can change even
         # without zconn.close/zconn.open, e.g.:
@@ -175,11 +176,14 @@ class ZSync:
         # tm.commit()   # zconn.at updated again
         zconn.onResyncCallback(zsync)
 
-    # TODO zconn dealloc -> wconn.close
+    # .zconn dealloc -> wconn.close
+    def on_zconn_dealloc(zsync, _):
+        zsync.wconn.close()
 
     # DB resyncs .zconn onto new database view.
     # -> resync .wconn to updated database view of ZODB connection.
     def on_connection_resync(zsync):
         #print('\nZZZSync.resync %r %r' % (zsync.zconn, zsync.wconn))
         #import traceback; traceback.print_stack()
-        zsync.wconn.resync(zconn_at(zsync.zconn))
+        zconn = zsync.zconn_ref()
+        zsync.wconn.resync(zconn_at(zconn))