fixed bug when moving MP_Nodes, patched by Matt Hoskins, fixes bug dj…

…ango-treebeard#27

CHANGES

@@ -1,5 +1,5 @@
 
-Release 1.6X (XXX XX, 2010)
+Release 1.6X (XXX XX, 2011)
 ---------------------------
 
 * Revamped admin interface for MP and NS trees, supporting drag&drop to reorder
@@ -14,6 +14,7 @@ Release 1.6X (XXX XX, 2010)
 * Added tox support
 * Fixed the test suite to run in Python 2.4
 * Fixed drag&drop bug in the admin (fixed by jmbarbier)
+* Fixed a bug when moving MP_Nodes (fixed by Matt Hoskins)
 
 Release 1.61 (Jul 24, 2010)
 ---------------------------

treebeard/mp_tree.py

@@ -753,7 +753,39 @@ def _move_add_sibling_aux(cls, pos, newpos, newdepth, target, siblings,
 
             newpath = cls._get_path(target.path, newdepth, newpos)
 
-            for node in siblings.reverse():
+            # If the move is amongst siblings and is to the left and there
+            # are siblings to the right of its new position then to be on
+            # the safe side we temporarily dump it on the end of the list
+            tempnewpath = None
+            if movebranch and len(oldpath) == len(newpath):
+                parentoldpath = cls._get_basepath(oldpath,
+                    (len(oldpath) / cls.steplen) - 1)
+                parentnewpath = cls._get_basepath(newpath, newdepth - 1)
+                if (parentoldpath == parentnewpath and siblings and
+                        newpath < oldpath):
+                    last = target.get_last_sibling()
+                    basenum = cls._get_lastpos_in_path(last.path)
+                    tempnewpath = cls._get_path(newpath, newdepth, basenum + 2)
+                    stmts.append(cls._get_sql_newpath_in_branches(oldpath,
+                                                               tempnewpath))
+
+            # Optimisation to only move siblings which need moving
+            # (i.e. if we've got holes, allow them to compress)
+            movesiblings = []
+            priorpath = newpath
+            for node in siblings:
+                # If the path of the node is already greater than the path
+                # of the previous node it doesn't need shifting
+                if node.path > priorpath:
+                    break
+                # It does need shifting, so add to the list
+                movesiblings.append(node)
+                # Calculate the path that it would be moved to, as that's
+                # the next "priorpath"
+                priorpath = cls._inc_path(node.path)
+            movesiblings.reverse()
+
+            for node in movesiblings:
                 # moving the siblings (and their branches) at the right of the
                 # related position one step to the right
                 sql, vals = cls._get_sql_newpath_in_branches(node.path,
@@ -772,8 +804,12 @@ def _move_add_sibling_aux(cls, pos, newpos, newdepth, target, siblings,
                         target.path = vals[0] + target.path[len(vals[0]):]
             if movebranch:
                 # node to move
-                stmts.append(cls._get_sql_newpath_in_branches(oldpath,
-                                                               newpath))
+                if tempnewpath:
+                    stmts.append(cls._get_sql_newpath_in_branches(tempnewpath,
+                                                                  newpath))
+                else:
+                    stmts.append(cls._get_sql_newpath_in_branches(oldpath,
+                                                                  newpath))
         return oldpath, newpath
 
     def _fix_move_to_child(self, pos, target, newdepth):
@@ -864,7 +900,7 @@ def _get_sql_newpath_in_branches(cls, oldpath, newpath):
 
         sql2 = ["path=%s" % (sqlpath, )]
         vals = [newpath, len(oldpath) + 1]
-        if (len(oldpath) != len(newpath) and 
+        if (len(oldpath) != len(newpath) and
                 cls.get_database_engine() != 'mysql'):
             # when using mysql, this won't update the depth and it has to be
             # done in another query

treebeard/tests/tests.py

@@ -1475,6 +1475,37 @@ def _multi_move_sorted(self):
                     (4, 1, u'fgh', 2, 0)]
         self.assertEqual(self.got(), expected)
 
+    def _multi_move_sortedsibling(self):
+            # https://bitbucket.org/tabo/django-treebeard/issue/27
+            self.sorted_model.add_root(val1=3, val2=3, desc='zxy')
+            self.sorted_model.add_root(val1=1, val2=4, desc='bcd')
+            self.sorted_model.add_root(val1=2, val2=5, desc='zxy')
+            self.sorted_model.add_root(val1=3, val2=3, desc='abc')
+            self.sorted_model.add_root(val1=4, val2=1, desc='fgh')
+            self.sorted_model.add_root(val1=3, val2=3, desc='abc')
+            self.sorted_model.add_root(val1=2, val2=2, desc='qwe')
+            self.sorted_model.add_root(val1=3, val2=2, desc='vcx')
+            root_nodes = self.sorted_model.get_root_nodes()
+            target = root_nodes[0]
+            for node in root_nodes[1:]:
+
+                # because raw queries don't update django objects
+                node = self.sorted_model.objects.get(pk=node.id)
+                target = self.sorted_model.objects.get(pk=target.id)
+
+                node.val1 = node.val1 - 2
+                node.save()
+                node.move(target, 'sorted-sibling')
+            expected = [(0, 2, u'qwe', 1, 0),
+                        (0, 5, u'zxy', 1, 0),
+                        (1, 2, u'vcx', 1, 0),
+                        (1, 3, u'abc', 1, 0),
+                        (1, 3, u'abc', 1, 0),
+                        (1, 3, u'zxy', 1, 0),
+                        (1, 4, u'bcd', 1, 0),
+                        (2, 1, u'fgh', 1, 0)]
+            self.assertEqual(self.got(), expected)
+
 
 class TestMP_TreeAlphabet(TestCase):