Bug#14171: Wrong internal default value for a BINARY field.

A BINARY field is represented by the Field_string class. The space character
is used as the filler for unused characters in such a field. But a BINARY field 
should use \x00 instead.

Field_string:reset() now detects whether the current field is a BINARY one
and if so uses the \x00 character as a default value filler.

mysql-test/r/type_binary.result

@@ -136,4 +136,13 @@ insert into t1 values(NULL, 0x412020);
 ERROR 22001: Data too long for column 'vb' at row 1
 drop table t1;
 set @@sql_mode= @old_sql_mode;
+create table t1(f1 int, f2 binary(2) not null, f3 char(2) not null);
+insert into t1 set f1=1;
+Warnings:
+Warning	1364	Field 'f2' doesn't have a default value
+Warning	1364	Field 'f3' doesn't have a default value
+select hex(f2), hex(f3) from t1;
+hex(f2)	hex(f3)
+0000	
+drop table t1;
 End of 5.0 tests

mysql-test/t/type_binary.test

@@ -91,4 +91,12 @@ insert into t1 values(NULL, 0x412020);
 drop table t1;
 set @@sql_mode= @old_sql_mode;
 
+#
+# Bug#14171: Wrong default value for a BINARY field
+#
+create table t1(f1 int, f2 binary(2) not null, f3 char(2) not null);
+insert into t1 set f1=1;
+select hex(f2), hex(f3) from t1;
+drop table t1;
+
 --echo End of 5.0 tests

sql/field.h

@@ -1034,7 +1034,8 @@ public:
   bool zero_pack() const { return 0; }
   int reset(void)
   {
-    charset()->cset->fill(charset(),ptr,field_length,' ');
+    charset()->cset->fill(charset(),ptr,field_length,
+                          (has_charset() ? ' ' : 0));
     return 0;
   }
   int store(const char *to,uint length,CHARSET_INFO *charset);