looks like most of the issues are because we're losing insert ordering

on cycles.  so lets reintroduce the organize as tree component, which
works here.   still need to make it meaningful by teaching the save/delete state
actions to receive a set of items to match up

diff --git a/lib/sqlalchemy/orm/unitofwork.py b/lib/sqlalchemy/orm/unitofwork.py
index 432e2e238817074c9dc33287a75f6ec32bac505a..9f888f8672408d6025f248e301e8ea9f3e6995f9 100644 (file)
--- a/lib/sqlalchemy/orm/unitofwork.py
+++ b/lib/sqlalchemy/orm/unitofwork.py
@@ -219,8 +219,21 @@ class UOWTransaction(object):
         print "------------------------"
         print self.dependencies
         print sort
-        for rec in sort:
-            rec.execute(self)
+        
+        if cycles:
+            # organize into a tree so that groups of nodes can be 
+            # merged together, allowing better maintenance of insert
+            # ordering and other things
+            (head, children) = topological.organize_as_tree(self.dependencies, sort)
+            stack = [(head, children)]
+            
+            while stack:
+                node, children = stack.pop()
+                node.execute(self)
+                stack += children
+        else:
+            for rec in sort:
+                rec.execute(self)
             
 
     def finalize_flush_changes(self):

diff --git a/lib/sqlalchemy/topological.py b/lib/sqlalchemy/topological.py
index bcf47bd6492bf4a4c2b3236d61690b24dddc32bc..7253cdc4d89d1ad632e2f1faed2bef330e4b64d0 100644 (file)
--- a/lib/sqlalchemy/topological.py
+++ b/lib/sqlalchemy/topological.py
@@ -114,3 +114,50 @@ def find_cycles(tuples, allitems):
             else:
                 node = stack.pop()
     return output
+
+
+def organize_as_tree(tuples, allitems):
+    """Given a list of sorted nodes from a topological sort, organize the
+    nodes into a tree structure, with as many non-dependent nodes
+    set as siblings to each other as possible.
+
+    returns nodes as tuples (item, children).
+    """
+
+    nodes = allitems
+    edges = _EdgeCollection(tuples)
+    children = util.defaultdict(list)
+    
+    if not nodes:
+        return None
+    # a list of all currently independent subtrees as a tuple of
+    # (root_node, set_of_all_tree_nodes, set_of_all_cycle_nodes_in_tree)
+    # order of the list has no semantics for the algorithmic
+    independents = []
+    # in reverse topological order
+    for node in reversed(nodes):
+        # nodes subtree and cycles contain the node itself
+        subtree = set([node])
+        # get a set of dependent nodes of node and its cycles
+        nodealldeps = edges.outgoing(node)
+        if nodealldeps:
+            # iterate over independent node indexes in reverse order so we can efficiently remove them
+            for index in xrange(len(independents) - 1, -1, -1):
+                child, childsubtree = independents[index]
+                # if there is a dependency between this node and an independent node
+                if (childsubtree.intersection(nodealldeps)):
+                    # prepend child to nodes children
+                    # (append should be fine, but previous implemetation used prepend)
+                    children[node][0:0] = [(child, children[child])]
+                    # merge childs subtree and cycles
+                    subtree.update(childsubtree)
+                    # remove the child from list of independent subtrees
+                    independents[index:index+1] = []
+        # add node as a new independent subtree
+        independents.append((node, subtree))
+    # choose an arbitrary node from list of all independent subtrees
+    head = independents.pop()[0]
+    # add all other independent subtrees as a child of the chosen root
+    # used prepend [0:0] instead of extend to maintain exact behaviour of previous implementation
+    children[head][0:0] = [(i[0], children[i[0]]) for i in independents]
+    return (head, children[head])

diff --git a/test/orm/test_unitofworkv2.py b/test/orm/test_unitofworkv2.py
index 5dd334d6e860a23f3d85abf355702fc4734aed47..e532b14fe6bc63c655873960336cd5690830b615 100644 (file)
--- a/test/orm/test_unitofworkv2.py
+++ b/test/orm/test_unitofworkv2.py
@@ -371,4 +371,26 @@ class SingleCycleTest(UOWTest):
         
         sess.delete(n1)
         sess.delete(n3)
-        sess.flush()
\ No newline at end of file
+        sess.flush()
+        
+    def test_bidirectional_multilevel_save(self):
+        mapper(Node, nodes, properties={
+            'children':relationship(Node, 
+                backref=backref('parent', remote_side=nodes.c.id)
+            )
+        })
+        sess = create_session()
+        n1 = Node(data='n1')
+        n1.children.append(Node(data='n11'))
+        n1.children.append(Node(data='n12'))
+        n1.children.append(Node(data='n13'))
+        n1.children[1].children.append(Node(data='n121'))
+        n1.children[1].children.append(Node(data='n122'))
+        n1.children[1].children.append(Node(data='n123'))
+        sess.add(n1)
+        sess.flush()
+#        self.assert_sql_execution(
+#                testing.db,
+ #               sess.flush,
+ #       )
+        
\ No newline at end of file