From 67a3d9e4d0356665728298097578931c7c5bae1f Mon Sep 17 00:00:00 2001
From: Ramil Kalimullin <ramil@mysql.com>
Date: Fri, 15 Aug 2008 10:53:25 +0500
Subject: [PATCH] Fix for bug#37337: Function returns different results

Problem: REGEXP in functions/PSs may return wrong results
due to improper initialization.

Fix: initialize required REGEXP params.


sql/item_cmpfunc.cc:
  Fix for bug#37337: Function returns different results

  prev_regexp is used in the Item_func_regex::regcomp()
  to store previous regex and to avoid re-initialization
  if given the same pattern.
  Shoud be deleted in the Item_func_regex::cleanup() where we
  clean up the regexp structure.
---
 mysql-test/r/func_regexp.result | 18 ++++++++++++++++++
 mysql-test/t/func_regexp.test   | 17 +++++++++++++++++
 sql/item_cmpfunc.cc             |  1 +
 3 files changed, 36 insertions(+)

diff --git a/mysql-test/r/func_regexp.result b/mysql-test/r/func_regexp.result
index 794ae79973a..b64f0b7f1c1 100644
--- a/mysql-test/r/func_regexp.result
+++ b/mysql-test/r/func_regexp.result
@@ -115,3 +115,21 @@ SELECT 1 REGEXP NULL;
 1 REGEXP NULL
 NULL
 End of 5.0 tests
+CREATE TABLE t1(a INT, b CHAR(4));
+INSERT INTO t1 VALUES (1, '6.1'), (1, '7.0'), (1, '8.0');
+PREPARE stmt1 FROM "SELECT a FROM t1 WHERE a=1 AND '7.0' REGEXP b LIMIT 1";
+EXECUTE stmt1;
+a
+1
+EXECUTE stmt1;
+a
+1
+EXECUTE stmt1;
+a
+1
+EXECUTE stmt1;
+a
+1
+DEALLOCATE PREPARE stmt1;
+DROP TABLE t1;
+End of 5.1 tests
diff --git a/mysql-test/t/func_regexp.test b/mysql-test/t/func_regexp.test
index 1b35fab9d54..f3677b8f5b0 100644
--- a/mysql-test/t/func_regexp.test
+++ b/mysql-test/t/func_regexp.test
@@ -65,3 +65,20 @@ drop table t1;
 SELECT 1 REGEXP NULL;
 
 --echo End of 5.0 tests
+
+
+#
+# Bug #37337: Function returns different results
+#
+CREATE TABLE t1(a INT, b CHAR(4));
+INSERT INTO t1 VALUES (1, '6.1'), (1, '7.0'), (1, '8.0');
+PREPARE stmt1 FROM "SELECT a FROM t1 WHERE a=1 AND '7.0' REGEXP b LIMIT 1";
+EXECUTE stmt1;
+EXECUTE stmt1;
+EXECUTE stmt1;
+EXECUTE stmt1;
+DEALLOCATE PREPARE stmt1;
+DROP TABLE t1;
+
+
+--echo End of 5.1 tests
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index c76bbececef..64a2049a37b 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -4592,6 +4592,7 @@ void Item_func_regex::cleanup()
   {
     my_regfree(&preg);
     regex_compiled=0;
+    prev_regexp.length(0);
   }
   DBUG_VOID_RETURN;
 }