Bug #20442523 CRASH WHEN CREATE TABLE VIOLATES FOREIGN KEY CONSTRAINT

Problem:

This is a coding mistake during error handling.  When the specified foreign
key constraint is wrong because of data type mismatch, the resulting
foreign key object will not have valid foreign->id (it will be NULL.)

Solution:

While removing the foreign key object from dictionary cache during error
handling, ensure that foreign->id is not null before using it.

rb#8204 approved by Sunny.

storage/innobase/dict/dict0dict.c

 /*****************************************************************************
 
-Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -2530,7 +2530,7 @@ dict_foreign_remove_from_cache(
 
 		rbt = foreign->referenced_table->referenced_rbt;
 
-		if (rbt != NULL) {
+		if (rbt != NULL && foreign->id != NULL) {
 			const ib_rbt_node_t*	node
 				= rbt_lookup(rbt, foreign->id);
 			dict_foreign_t*	val = *(dict_foreign_t**) node->value;
@@ -2549,7 +2549,7 @@ dict_foreign_remove_from_cache(
 			       foreign);
 		rbt = foreign->foreign_table->foreign_rbt;
 
-		if (rbt != NULL) {
+		if (rbt != NULL && foreign->id != NULL) {
 			const ib_rbt_node_t*	node
 				= rbt_lookup(rbt, foreign->id);
 			dict_foreign_t*	val = *(dict_foreign_t**) node->value;