MONDRIAN - Fixed construction of null member when ignore invalid members

       property is set and non-existent member found.

[git-p4: depot-paths = "//open/mondrian/": change = 8181]

src/main/mondrian/olap/Util.java

@@ -594,23 +594,31 @@ public static Exp lookup(
                                 createExpr(olapElement)});
                 }
             }
-            // if we're in the middle of loading the schema, the
-            // property has been set to ignore invalid members, and the member
-            // is non-existent, return the null member; find the null member
-            // by first finding a member at the same level and then
-            // getting the null member from that member's hierarchy; if
-            // we can't find a member of the specified hierarchy, then just
-            // return the null member from the first hierarchy
+            // if we're in the middle of loading the schema, the property has
+            // been set to ignore invalid members, and the member is
+            // non-existent, return the null member corresponding to the
+            // hierarchy of the element we're looking for; locate the
+            // hierarchy by incrementally truncating the name of the element
             if (q.ignoreInvalidMembers()) {
-                olapElement = schemaReader.lookupCompound(
-                    q.getCube(), nameParts, false, Category.Member, 
-                    MatchType.BEFORE);
+                int nameLen = nameParts.length - 1;
+                olapElement = null;
+                while (nameLen > 0 && olapElement == null) {
+                    String[] partialName = new String[nameLen];
+                    System.arraycopy(
+                        nameParts,
+                        0,
+                        partialName,
+                        0,
+                        nameLen);
+                    olapElement = schemaReader.lookupCompound(
+                        q.getCube(), partialName, false, Category.Unknown);
+                    nameLen--;
+                }
                 if (olapElement != null) {
                     olapElement = olapElement.getHierarchy().getNullMember();
                 } else {
-                    olapElement =
-                        q.getCube().getDimensions()[0].getHierarchy().
-                            getNullMember();
+                    throw MondrianResource.instance().MdxChildObjectNotFound.ex(
+                        fullName, q.getCube().getQualifiedName());
                 }
             } else {    
                 throw MondrianResource.instance().MdxChildObjectNotFound.ex(