From 99f1606e942985d4a803c2914eb25fe4fc61c338 Mon Sep 17 00:00:00 2001
From: "gkodinov/kgeorge@magare.gmz" <>
Date: Thu, 11 Oct 2007 11:29:26 +0300
Subject: [PATCH] Bug #31440: 'select 1 regex null' asserts debug server

The special case with NULL as a regular expression
was handled at prepare time. But in this special case
the item was not marked as fixed. This caused an assertion
at execution time.
Fixed my marking the item as fixed even when known to
return NULL at prepare time.
---
 mysql-test/r/func_regexp.result |  5 +++++
 mysql-test/t/func_regexp.test   | 11 ++++++++++-
 sql/item_cmpfunc.cc             |  1 +
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/func_regexp.result b/mysql-test/r/func_regexp.result
index 584c8a9b820..2366947d2a7 100644
--- a/mysql-test/r/func_regexp.result
+++ b/mysql-test/r/func_regexp.result
@@ -98,3 +98,8 @@ R2
 R3
 deallocate prepare stmt1;
 drop table t1;
+End of 4.1 tests
+SELECT 1 REGEXP NULL;
+1 REGEXP NULL
+NULL
+End of 5.0 tests
diff --git a/mysql-test/t/func_regexp.test b/mysql-test/t/func_regexp.test
index 23070c71fe9..5eff404bc0f 100644
--- a/mysql-test/t/func_regexp.test
+++ b/mysql-test/t/func_regexp.test
@@ -74,4 +74,13 @@ execute stmt1 using @a;
 deallocate prepare stmt1;
 drop table t1;
 
-# End of 4.1 tests
+--echo End of 4.1 tests
+
+
+#
+# Bug #31440: 'select 1 regex null' asserts debug server
+#
+
+SELECT 1 REGEXP NULL;
+
+--echo End of 5.0 tests
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 1599bcc1571..a5ede9e757c 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -4285,6 +4285,7 @@ Item_func_regex::fix_fields(THD *thd, Item **ref)
     if (args[1]->null_value)
     {						// Will always return NULL
       maybe_null=1;
+      fixed= 1;
       return FALSE;
     }
     int error;