BUG#952583: Server crashes in Item_field::fix_after_pullout on INSERT .. SELECT

- Take into account that there may exist Item_field objects with context==NULL.

mysql-test/r/subselect_sj.result

@@ -2628,4 +2628,15 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 drop table t0,t1,t3;
 set optimizer_switch= @tmp_923246;
+#
+# BUG#952583: Server crashes in Item_field::fix_after_pullout on INSERT .. SELECT
+# 
+CREATE TABLE t1 ( a INT );
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (3),(4);
+INSERT INTO t1
+SELECT * FROM ( SELECT * FROM t1 ) AS alias
+WHERE a IN ( SELECT b FROM t2 );
+DROP TABLE t1, t2;
 set optimizer_switch=@subselect_sj_tmp;

mysql-test/r/subselect_sj_jcl6.result

@@ -2642,6 +2642,17 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 drop table t0,t1,t3;
 set optimizer_switch= @tmp_923246;
+#
+# BUG#952583: Server crashes in Item_field::fix_after_pullout on INSERT .. SELECT
+# 
+CREATE TABLE t1 ( a INT );
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (3),(4);
+INSERT INTO t1
+SELECT * FROM ( SELECT * FROM t1 ) AS alias
+WHERE a IN ( SELECT b FROM t2 );
+DROP TABLE t1, t2;
 set optimizer_switch=@subselect_sj_tmp;
 #
 # BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off

mysql-test/t/subselect_sj.test

@@ -2331,5 +2331,19 @@ explain select * from t3 where a in (select kp1 from t1 where kp1<20);
 drop table t0,t1,t3;
 set optimizer_switch= @tmp_923246;
 
+--echo #
+--echo # BUG#952583: Server crashes in Item_field::fix_after_pullout on INSERT .. SELECT
+--echo # 
+CREATE TABLE t1 ( a INT );
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (3),(4);
+
+INSERT INTO t1
+SELECT * FROM ( SELECT * FROM t1 ) AS alias
+WHERE a IN ( SELECT b FROM t2 );
+
+DROP TABLE t1, t2;
+
 # The following command must be the last one the file 
 set optimizer_switch=@subselect_sj_tmp;

sql/item.cc

@@ -2436,6 +2436,8 @@ void Item_field::fix_after_pullout(st_select_lex *new_parent, Item **ref)
 {
   if (new_parent == get_depended_from())
     depended_from= NULL;
+  if (context)
+  {
     Name_resolution_context *ctx= new Name_resolution_context();
     ctx->outer_context= NULL; // We don't build a complete name resolver
     ctx->table_list= NULL;    // We rely on first_name_resolution_table instead
@@ -2447,6 +2449,7 @@ void Item_field::fix_after_pullout(st_select_lex *new_parent, Item **ref)
     ctx->resolve_in_select_list=      context->resolve_in_select_list;
     ctx->security_ctx=                context->security_ctx;
     this->context=ctx;
+  }
 }