Bug#17226: Variable set in cursor on first iteration is assigned

           second iterations value

During assignment to the BLOB variable in routine body the value
wasn't copied.

Author: kroki@mysql.com

mysql-test/r/sp-vars.result

@@ -1075,3 +1075,18 @@ SELECT f1();
 f1()
 abc
 DROP FUNCTION f1;
+DROP PROCEDURE IF EXISTS p1;
+CREATE PROCEDURE p1()
+BEGIN
+DECLARE v_char VARCHAR(255);
+DECLARE v_text TEXT DEFAULT '';
+SET v_char = 'abc';
+SET v_text = v_char;
+SET v_char = 'def';
+SET v_text = concat(v_text, '|', v_char);
+SELECT v_text;
+END|
+CALL p1();
+v_text
+abc|def
+DROP PROCEDURE p1;

mysql-test/t/sp-vars.test

@@ -1271,3 +1271,39 @@ SELECT f1();
 #
 
 DROP FUNCTION f1;
+
+
+#
+# Bug#17226: Variable set in cursor on first iteration is assigned
+# second iterations value
+#
+# The problem was in incorrect handling of local variables of type
+# TEXT (BLOB).
+#
+--disable_warnings
+DROP PROCEDURE IF EXISTS p1;
+--enable_warnings
+
+delimiter |;
+CREATE PROCEDURE p1()
+BEGIN
+  DECLARE v_char VARCHAR(255);
+  DECLARE v_text TEXT DEFAULT '';
+
+  SET v_char = 'abc';
+
+  SET v_text = v_char;
+
+  SET v_char = 'def';
+
+  SET v_text = concat(v_text, '|', v_char);
+
+  SELECT v_text;
+END|
+delimiter ;|
+
+CALL p1();
+
+DROP PROCEDURE p1;
+
+# End of 5.0 tests.

sql/field_conv.cc

@@ -675,9 +675,14 @@ void field_conv(Field *to,Field *from)
   {						// Be sure the value is stored
     Field_blob *blob=(Field_blob*) to;
     from->val_str(&blob->value);
-    if (!blob->value.is_alloced() &&
-	from->real_type() != MYSQL_TYPE_STRING &&
-        from->real_type() != MYSQL_TYPE_VARCHAR)
+    /*
+      Copy value if copy_blobs is set, or source is not a string and
+      we have a pointer to its internal string conversion buffer.
+    */
+    if (to->table->copy_blobs ||
+        (!blob->value.is_alloced() &&
+         from->real_type() != MYSQL_TYPE_STRING &&
+         from->real_type() != MYSQL_TYPE_VARCHAR))
       blob->value.copy();
     blob->store(blob->value.ptr(),blob->value.length(),from->charset());
     return;