BUG#19140: Create index caused crash

mysql-test/r/ndb_partition_key.result:
  New test case to ensure path in code is tested
mysql-test/r/partition.result:
  New test case for bug
mysql-test/t/ndb_partition_key.test:
  New test case to ensure path in code is tested
mysql-test/t/partition.test:
  New test case for bug
sql/sql_partition.cc:
  Use stack variable, not variable on lex object, caused havoc when doing a create index.
sql/sql_table.cc:
  Editorial changes + added a comment to a path in code I didn't remember myself what it was good for.

mysql-test/r/ndb_partition_key.result

@@ -197,3 +197,7 @@ ENGINE=NDB
 PARTITION BY KEY(c3);
 ALTER TABLE t1 ADD COLUMN c4 INT AFTER c1;
 DROP TABLE t1;
+CREATE TABLE t1 (a int)
+PARTITION BY KEY(a)
+(PARTITION p0 ENGINE = NDB);
+DROP TABLE t1;

mysql-test/r/partition.result

@@ -886,4 +886,9 @@ s1
 2
 3
 drop table t1;
+create table t1 (a int) engine=memory
+partition by key(a);
+insert into t1 values (1);
+create index inx1 on t1(a);
+drop table t1;
 End of 5.1 tests

mysql-test/t/ndb_partition_key.test

@@ -196,3 +196,10 @@ CREATE TABLE t1 (
 
 ALTER TABLE t1 ADD COLUMN c4 INT AFTER c1;
 DROP TABLE t1;
+
+CREATE TABLE t1 (a int)
+PARTITION BY KEY(a)
+(PARTITION p0 ENGINE = NDB);
+DROP TABLE t1;
+
+

mysql-test/t/partition.test

@@ -9,6 +9,11 @@
 drop table if exists t1;
 --enable_warnings
 
+create table t1 (a int)
+partition by key(a)
+(partition p0 engine = MEMORY);
+drop table t1;
+
 #
 # Partition by key no partition defined => OK
 #
@@ -1009,4 +1014,13 @@ select auto_increment from information_schema.tables where table_name='t1';
 select * from t1;
 drop table t1;
 
+#
+# BUG 19140 Partitions: Create index for partitioned table crashes
+#
+create table t1 (a int) engine=memory
+partition by key(a);
+insert into t1 values (1);
+create index inx1 on t1(a);
+drop table t1;
+
 --echo End of 5.1 tests

sql/sql_partition.cc

@@ -4509,7 +4509,7 @@ the generated partition syntax in a correct manner.
       if (alter_info->flags & ALTER_REMOVE_PARTITIONING)
       {
         DBUG_PRINT("info", ("Remove partitioning"));
-        if (!(thd->lex->create_info.used_fields & HA_CREATE_USED_ENGINE))
+        if (!(create_info->used_fields & HA_CREATE_USED_ENGINE))
         {
           DBUG_PRINT("info", ("No explicit engine used"));
           create_info->db_type= table->part_info->default_engine_type;
@@ -4526,7 +4526,7 @@ the generated partition syntax in a correct manner.
           beneath.
         */
         thd->work_part_info= table->part_info;
-        if (thd->lex->create_info.used_fields & HA_CREATE_USED_ENGINE &&
+        if (create_info->used_fields & HA_CREATE_USED_ENGINE &&
             create_info->db_type != table->part_info->default_engine_type)
         {
           /*

sql/sql_table.cc

@@ -3105,8 +3105,8 @@ bool mysql_create_table_internal(THD *thd,
     }
     DBUG_PRINT("info", ("db_type = %d",
                          ha_legacy_type(part_info->default_engine_type)));
-    if (part_info->check_partition_info( &engine_type, file,
-                             create_info->max_rows))
+    if (part_info->check_partition_info(&engine_type, file,
+                                        create_info->max_rows))
       goto err;
     part_info->default_engine_type= engine_type;
 
@@ -3165,6 +3165,12 @@ bool mysql_create_table_internal(THD *thd,
     }
     else if (create_info->db_type != engine_type)
     {
+      /*
+        We come here when we don't use a partitioned handler.
+        Since we use a partitioned table it must be "native partitioned".
+        We have switched engine from defaults, most likely only specified
+        engines in partition clauses.
+      */
       delete file;
       if (!(file= get_new_handler((TABLE_SHARE*) 0, thd->mem_root, engine_type)))
       {