From 25e32d83d6d5fdce25ba4ef68885ffbf9f7a934f Mon Sep 17 00:00:00 2001
From: unknown <gvb@phoenix.(none)>
Date: Fri, 13 Jan 2006 14:42:46 +0100
Subject: [PATCH] fix for bug#15828 problem was not checking 2nd parameter of
 str_to_date against NULL

mysql-test/r/date_formats.result:
  bk commit
---
 mysql-test/r/date_formats.result | 6 ++++++
 mysql-test/t/date_formats.test   | 7 +++++++
 sql/item_timefunc.cc             | 2 +-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/date_formats.result b/mysql-test/r/date_formats.result
index 34a2dedd976..b2dc1f7a67b 100644
--- a/mysql-test/r/date_formats.result
+++ b/mysql-test/r/date_formats.result
@@ -464,3 +464,9 @@ d1	d2
 02	February
 01	January
 drop table t1;
+select str_to_date( 1, NULL );
+str_to_date( 1, NULL )
+NULL
+select str_to_date( NULL, 1 );
+str_to_date( NULL, 1 )
+NULL
diff --git a/mysql-test/t/date_formats.test b/mysql-test/t/date_formats.test
index 6d501865d2c..dd31f1509c0 100644
--- a/mysql-test/t/date_formats.test
+++ b/mysql-test/t/date_formats.test
@@ -268,4 +268,11 @@ insert into t1 (f1) values ("2005-01-01");
 insert into t1 (f1) values ("2005-02-01");
 select date_format(f1, "%m") as d1, date_format(f1, "%M") as d2 from t1 order by date_format(f1, "%M");
 drop table t1;
+
+#
+# Bug #15828
+#
+select str_to_date( 1, NULL );
+select str_to_date( NULL, 1 );
+
 # End of 4.1 tests
diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index eb58b180ed7..d060612c9f6 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -2750,7 +2750,7 @@ void Item_func_str_to_date::fix_length_and_dec()
   cached_field_type= MYSQL_TYPE_STRING;
   max_length= MAX_DATETIME_FULL_WIDTH*MY_CHARSET_BIN_MB_MAXLEN;
   cached_timestamp_type= MYSQL_TIMESTAMP_NONE;
-  if ((const_item= args[1]->const_item()))
+  if ((const_item= args[1]->const_item()) && !args[1]->null_value)
   {
     format= args[1]->val_str(&format_str);
     cached_format_type= get_date_time_result_type(format->ptr(),