Bug #21086: server crashes when VIEW defined with a SELECT with COLLATE clause is called

  When executing INSERT over a view with calculated columns it was assuming all
  elements of the fields collection are actually Item_field instances.
  This may not be true when inserting into a view and that view has columns that are 
  such expressions that allow updating (like setting a collation for example).
  Corrected to access field information through the filed_for_view_update() function and 
  retrieve correctly the field info even for "update-friendly" non-Item_field items.

mysql-test/r/view.result

@@ -2807,3 +2807,16 @@ yadda
 yad
 DROP VIEW v1;
 DROP TABLE t1;
+CREATE TABLE t1 (s1 char);
+INSERT INTO t1 VALUES ('Z');
+CREATE VIEW v1 AS SELECT s1 collate latin1_german1_ci AS col FROM t1;
+CREATE VIEW v2 (col) AS SELECT s1 collate latin1_german1_ci FROM t1;
+INSERT INTO v1 (col) VALUES ('b');
+INSERT INTO v2 (col) VALUES ('c');
+SELECT s1 FROM t1;
+s1
+Z
+b
+c
+DROP VIEW v1, v2;
+DROP TABLE t1;

mysql-test/t/view.test

@@ -2667,3 +2667,22 @@ SELECT * FROM v1;
 DROP VIEW v1;
 
 DROP TABLE t1;
+
+#
+# Bug #21086: server crashes when VIEW defined with a SELECT with COLLATE 
+# clause is called
+#
+CREATE TABLE t1 (s1 char);
+INSERT INTO t1 VALUES ('Z');
+
+CREATE VIEW v1 AS SELECT s1 collate latin1_german1_ci AS col FROM t1;
+
+CREATE VIEW v2 (col) AS SELECT s1 collate latin1_german1_ci FROM t1;
+
+# either of these statements will cause crash
+INSERT INTO v1 (col) VALUES ('b');
+INSERT INTO v2 (col) VALUES ('c');
+
+SELECT s1 FROM t1;
+DROP VIEW v1, v2;
+DROP TABLE t1;

sql/item_strfunc.h

@@ -728,7 +728,7 @@ public:
   void fix_length_and_dec();
   bool eq(const Item *item, bool binary_cmp) const;
   const char *func_name() const { return "collate"; }
-  enum Functype func_type() const { return COLLATE_FUNC; }
+  enum Functype functype() const { return COLLATE_FUNC; }
   void print(String *str);
   Item_field *filed_for_view_update()
   {

sql/sql_base.cc

@@ -4959,12 +4959,17 @@ fill_record(THD * thd, List<Item> &fields, List<Item> &values,
             bool ignore_errors)
 {
   List_iterator_fast<Item> f(fields),v(values);
-  Item *value;
+  Item *value, *fld;
   Item_field *field;
   DBUG_ENTER("fill_record");
 
-  while ((field=(Item_field*) f++))
+  while ((fld= f++))
   {
+    if (!(field= fld->filed_for_view_update()))
+    {
+      my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), fld->name);
+      DBUG_RETURN(TRUE);
+    }
     value=v++;
     Field *rfield= field->field;
     TABLE *table= rfield->table;