.

wcfs/testprog/treegen.py

@@ -152,18 +152,24 @@ def Trees(zstor, r):
     defer(zctx.close)
 
     ztree = zctx.root['treegen/tree'] = XLOTree()
-    at0 = commit('treegen/tree: init')
-    xprint("start @%s root=%s" % (ashex(at0), ashex(ztree._p_oid)))
+    head = commit('treegen/tree: init')
+    xprint("start @%s root=%s" % (ashex(head), ashex(ztree._p_oid)))
+    treetxtPrev = zctx.TopoEncode(ztree)
 
     while 1:
         treetxt = r.readline()
         if treetxt == '':
             break # EOF
-
         treetxt = treetxt.rstrip()  # trim trailing \n
+
+        # skip changing DB if the same topology is requested twice
+        # (this avoids assert in commit that len(resources) == 1)
+        if treetxt == treetxtPrev:
+            xprint("%s" % ashex(head))
+            continue
+        treetxtPrev = treetxt
+
         tree = zctx.TopoDecode(treetxt)
-#       ztree = trees[treetxt] = XLOTree()
-#       zctx.zconn.add(ztree) # so that restructure can see we are working under zconn
 
         # treekv[k]=v for all k
         # do tree.keys() via walkBFS
@@ -184,11 +190,11 @@ def Trees(zstor, r):
         # restructure ztree to requested topology
         xbtree.Restructure(ztree, tree)
 
-        tid = commit("treegen/trees: %s" % treetxt)
+        head = commit("treegen/trees: %s" % treetxt)
         # XXX print more details?
         # XXX print just tid (as `zodb commit` does) ?
-        #print("txn %s -> tree(%s) %s" % (ashex(tid), ashex(ztree._p_oid), treetxt))
-        print("%s" % ashex(tid))
+        #xprint("txn %s -> tree(%s) %s" % (ashex(tid), ashex(ztree._p_oid), treetxt))
+        xprint("%s" % ashex(head))
 
 
 # AllStructs generates subset of all possible tree changes in

wcfs/δbtail_test.go

@@ -121,6 +121,7 @@ func (tg *TreeGen) Close() (err error) {
 // Commit creates new commit with underlying tree changed to tree topology.
 func (tg *TreeGen) Commit(tree string) (_ zodb.Tid, err error) {
 	defer xerr.Contextf(&err, "treegen %s: commit %s", tg.zurl, tree)
+	fmt.Printf("commit %s ...\n", tree)
 
 	_, err = io.WriteString(tg.pyin, tree + "\n")
 	if err != nil {