Merge with 4.0

mysql-test/r/func_str.result

@@ -201,6 +201,9 @@ hex(unhex("1"))	hex(unhex("12"))	hex(unhex("123"))	hex(unhex("1234"))	hex(unhex(
 select length(unhex(md5("abrakadabra")));
 length(unhex(md5("abrakadabra")))
 16
+select concat('a', quote(NULL));
+concat('a', quote(NULL))
+aNULL
 select reverse("");
 reverse("")
 
@@ -312,7 +315,7 @@ insert into t1 values ('one'),(NULL),('two'),('four');
 select a, quote(a), isnull(quote(a)), quote(a) is null, ifnull(quote(a), 'n') from t1;
 a	quote(a)	isnull(quote(a))	quote(a) is null	ifnull(quote(a), 'n')
 one	'one'	0	0	'one'
-NULL	NULL	1	1	n
+NULL	NULL	0	0	NULL
 two	'two'	0	0	'two'
 four	'four'	0	0	'four'
 drop table t1;

mysql-test/t/func_str.test

@@ -82,6 +82,12 @@ select unhex(hex("foobar")), hex(unhex("1234567890ABCDEF")), unhex("345678"), un
 select hex(unhex("1")), hex(unhex("12")), hex(unhex("123")), hex(unhex("1234")), hex(unhex("12345")), hex(unhex("123456"));
 select length(unhex(md5("abrakadabra")));
 
+#
+# Bug #6564: QUOTE(NULL
+#
+
+select concat('a', quote(NULL));
+
 #
 # Wrong usage of functions
 #

mysys/default.c

@@ -120,7 +120,7 @@ int load_defaults(const char *conf_file, const char **groups,
   uint args_used=0;
   int error= 0;
   MEM_ROOT alloc;
-  char *ptr, **res, **ext;
+  char *ptr, **res;
 
   DBUG_ENTER("load_defaults");
 
@@ -182,7 +182,6 @@ int load_defaults(const char *conf_file, const char **groups,
   }
   else if (dirname_length(conf_file))
   {
-    for (ext= (char**) f_extensions; *ext; *ext++)
     if ((error= search_default_file(&args, &alloc, NullS, conf_file,
 				    &group)) < 0)
       goto err;

sql/item_strfunc.cc

@@ -2562,9 +2562,12 @@ String* Item_func_inet_ntoa::val_str(String* str)
 
     This function is very useful when you want to generate SQL statements
 
+  NOTE
+    QUOTE(NULL) returns the string 'NULL' (4 letters, without quotes).
+
   RETURN VALUES
     str		Quoted string
-    NULL	Argument to QUOTE() was NULL or out of memory.
+    NULL	Out of memory.
 */
 
 #define get_esc_bit(mask, num) (1 & (*((mask) + ((num) >> 3))) >> ((num) & 7))
@@ -2589,7 +2592,12 @@ String *Item_func_quote::val_str(String *str)
   String *arg= args[0]->val_str(str);
   uint arg_length, new_length;
   if (!arg)					// Null argument
-    goto null;
+  {
+    str->copy("NULL", 4);			// Return the string 'NULL'
+    null_value= 0;
+    return str;
+  }
+
   arg_length= arg->length();
   new_length= arg_length+2; /* for beginning and ending ' signs */