bk commit into 4.1 tree (evgen:1.2361) BUG#11868

[eugene]

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ChangeSet
  1.2361 05/07/16 04:34:35 evgen@stripped +3 -0
  Fix bug#11868 Update with subquery crashes server
  
  Problem was in add_not_null_conds() optimization function.
  It contains following code:
  JOIN_TAB *referred_tab= not_null_item->field->table->reginfo.join_tab;
  ...
  add_cond_and_fix(&referred_tab->select_cond, notnull);
  For UPDATE described in bug report referred_tab is 0 and dereferencing it
  crashes the server.
  

  mysql-test/r/update.result
    1.23 05/07/16 04:34:08 evgen@stripped +11 -0
    Test case for bug#11868  update with subquery fails

  mysql-test/t/update.test
    1.20 05/07/16 04:33:34 evgen@stripped +12 -0
    Test case for bug#11868  update with subquery fails

  sql/sql_select.cc
    1.421 05/07/16 04:31:51 evgen@stripped +6 -1
    Fix bug #11868 update with subquery fails
    Added check for NULL before dereferencing pointer.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	evgen
# Host:	moonbone.local
# Root:	/work/mysql-4.1-bug-11868

--- 1.420/sql/sql_select.cc	2005-07-16 03:14:29 +04:00
+++ 1.421/sql/sql_select.cc	2005-07-16 04:31:51 +04:00
@@ -3555,7 +3555,12 @@
           DBUG_ASSERT(item->type() == Item::FIELD_ITEM);
           Item_field *not_null_item= (Item_field*)item;
           JOIN_TAB *referred_tab= not_null_item->field->table->reginfo.join_tab;
-          if (referred_tab->join != join)
+          /*
+            For UPDATE queries such as:
+            UPDATE t1 SET t1.f2=(SELECT MAX(t2.f4) FROM t2 WHERE t2.f3=t1.f1);
+            not_null_item is the t1.f1, but it's referred_tab is 0.
+          */
+          if (!referred_tab || referred_tab->join != join)
             continue;
           Item *notnull;
           if (!(notnull= new Item_func_isnotnull(not_null_item)))

--- 1.22/mysql-test/r/update.result	2005-04-18 05:21:40 +04:00
+++ 1.23/mysql-test/r/update.result	2005-07-16 04:34:08 +04:00
@@ -240,3 +240,14 @@
 show warnings;
 Level	Code	Message
 drop table t1, t2;
+create table t1(f1 int, f2 int);
+create table t2(f3 int, f4 int);
+create index idx on t2(f3);
+insert into t1 values(1,0),(2,0);
+insert into t2 values(1,1),(2,2);
+UPDATE t1 SET t1.f2=(SELECT MAX(t2.f4) FROM t2 WHERE t2.f3=t1.f1);
+select * from t1;
+f1	f2
+1	1
+2	2
+drop table t1,t2;

--- 1.19/mysql-test/t/update.test	2005-04-18 05:21:41 +04:00
+++ 1.20/mysql-test/t/update.test	2005-07-16 04:33:34 +04:00
@@ -201,3 +201,15 @@
 update t1, t2 set t1.a = t2.a where t2.b = t1.b;
 show warnings;
 drop table t1, t2;
+
+#
+# Bug #11868 update with subquery fails
+#
+create table t1(f1 int, f2 int);
+create table t2(f3 int, f4 int);
+create index idx on t2(f3);
+insert into t1 values(1,0),(2,0);
+insert into t2 values(1,1),(2,2);
+UPDATE t1 SET t1.f2=(SELECT MAX(t2.f4) FROM t2 WHERE t2.f3=t1.f1);
+select * from t1;
+drop table t1,t2;