Merge lp:~prafulla-t/drizzle/dr-bug-592473 into lp:~drizzle-trunk/drizzle/development

[Patrick Crews]

Contains a fix for https://bugs.launchpad.net/drizzle/+bug/592473
Crash/segfault in drizzled::subselect_single_select_engine::exec (this=0x19a7008) at drizzled/item/subselect.cc:2204

I have tested this patch with the randgen + regular test suite with no issues.
Tested various grammars against patched vs. unpatched drizzle with no differences in result sets (other than the original crash)
Also tested execution times with no reported differences.

[lp:~prafulla-t/drizzle/dr-bug-592473]

1641. By PrafullaT on 2010-07-03

Reverting some un-necessary changes.

[Brian Aker (brianaker)]

review: Approve

=== modified file 'drizzled/join.cc'
--- drizzled/join.cc	2010-06-25 19:38:04 +0000
+++ drizzled/join.cc	2010-07-03 03:10:43 +0000
@@ -497,6 +497,7 @@
     {           /* Impossible cond */
       zero_result_cause=  having_value == Item::COND_FALSE ?
                            "Impossible HAVING" : "Impossible WHERE";
+      tables = 0;
       goto setup_subq_exit;
     }
   }
@@ -516,6 +517,7 @@
       if (res == HA_ERR_KEY_NOT_FOUND)
       {
         zero_result_cause= "No matching min/max row";
+        tables = 0;
         goto setup_subq_exit;
       }
       if (res > 1)
@@ -526,10 +528,12 @@
       if (res < 0)
       {
         zero_result_cause= "No matching min/max row";
+        tables = 0;
         goto setup_subq_exit;
       }
       zero_result_cause= "Select tables optimized away";
       tables_list= 0;       // All tables resolved
+      const_tables= tables;
       /*
         Extract all table-independent conditions and replace the WHERE
         clause with them. All other conditions were computed by optimizer::sum_query