From f8f021fd6ba2f654b9b6a3731bc9fea84885687c Mon Sep 17 00:00:00 2001
From: unknown <mhansson/martin@linux-st28.site>
Date: Thu, 4 Oct 2007 09:15:26 +0200
Subject: [PATCH] Bug #30942: select str_to_date from derived table returns
 varying results

The function str_to_date has a field to say whether it's invoked constant
arguments. But this member was not initialized, causing the function to
think that it could use a cache of the format type when said cache was in
fact not initialized.
Fixed by initializing the field to false.


mysql-test/r/type_date.result:
  Bug#30942: Test result
mysql-test/t/type_date.test:
  Bug#30942: Test case
sql/item_timefunc.h:
  Bug#30942: Initialized const_item to false
---
 mysql-test/r/type_date.result | 10 ++++++++++
 mysql-test/t/type_date.test   | 13 +++++++++++++
 sql/item_timefunc.h           |  2 +-
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/type_date.result b/mysql-test/r/type_date.result
index 9f51fc0371c..53fe9710eba 100644
--- a/mysql-test/r/type_date.result
+++ b/mysql-test/r/type_date.result
@@ -136,3 +136,13 @@ d	dt	ts
 0000-00-00	0000-00-00 00:00:00	0000-00-00 00:00:00
 2001-11-11	2001-11-11 00:00:00	2001-11-11 00:00:00
 drop table t1;
+CREATE TABLE t1 (
+a INT
+);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (NULL);
+SELECT str_to_date( '', a ) FROM t1;
+str_to_date( '', a )
+0000-00-00 00:00:00
+NULL
+DROP TABLE t1;
diff --git a/mysql-test/t/type_date.test b/mysql-test/t/type_date.test
index 02cd07e3c16..aeb88f3acc2 100644
--- a/mysql-test/t/type_date.test
+++ b/mysql-test/t/type_date.test
@@ -136,3 +136,16 @@ insert into t1 values (9912101,9912101,9912101);
 insert into t1 values (11111,11111,11111);
 select * from t1;
 drop table t1;
+
+#
+# Bug #30942: select str_to_date from derived table returns varying results
+#
+CREATE TABLE t1 (
+  a INT
+);
+
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (NULL);
+
+SELECT str_to_date( '', a ) FROM t1;
+DROP TABLE t1;
diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
index 8e925a0156f..cb69bd200e6 100644
--- a/sql/item_timefunc.h
+++ b/sql/item_timefunc.h
@@ -1030,7 +1030,7 @@ class Item_func_str_to_date :public Item_str_func
   bool const_item;
 public:
   Item_func_str_to_date(Item *a, Item *b)
-    :Item_str_func(a, b)
+    :Item_str_func(a, b), const_item(false)
   {}
   String *val_str(String *str);
   bool get_date(MYSQL_TIME *ltime, uint fuzzy_date);