Bug#16172 DECIMAL data type processed incorrectly

issue an error in case of DECIMAL(M,N) if N > M


mysql-test/r/type_newdecimal.result:
  Bug#16172 DECIMAL data type processed incorrectly
  result fix & test case
mysql-test/t/type_newdecimal.test:
  Bug#16172 DECIMAL data type processed incorrectly
  test fix

mysql-test/r/type_newdecimal.result

@@ -915,9 +915,13 @@ drop table t1;
 select cast('1.00000001335143196001808973960578441619873046875E-10' as decimal(30,15));
 cast('1.00000001335143196001808973960578441619873046875E-10' as decimal(30,15))
 0.000000000100000
-select ln(14000) c1, convert(ln(14000),decimal(2,3)) c2, cast(ln(14000) as decimal(2,3)) c3;
+select ln(14000) c1, convert(ln(14000),decimal(5,3)) c2, cast(ln(14000) as decimal(5,3)) c3;
 c1	c2	c3
 9.5468126085974	9.547	9.547
+select convert(ln(14000),decimal(2,3)) c1;
+ERROR 42000: For float(M,D), double(M,D) or decimal(M,D), M must be >= D (column '').
+select cast(ln(14000) as decimal(2,3)) c1;
+ERROR 42000: For float(M,D), double(M,D) or decimal(M,D), M must be >= D (column '').
 create table t1 (sl decimal(70,30));
 ERROR 42000: Too big precision 70 specified for column 'sl'. Maximum is 65.
 create table t1 (sl decimal(32,31));

mysql-test/t/type_newdecimal.test

@@ -947,8 +947,12 @@ select cast('1.00000001335143196001808973960578441619873046875E-10' as decimal(3
 #
 # Bug #11708 (conversion to decimal fails in decimal part)
 #
-select ln(14000) c1, convert(ln(14000),decimal(2,3)) c2, cast(ln(14000) as decimal(2,3)) c3;
-
+select ln(14000) c1, convert(ln(14000),decimal(5,3)) c2, cast(ln(14000) as decimal(5,3)) c3;
+--error 1427
+select convert(ln(14000),decimal(2,3)) c1;
+--error 1427
+select cast(ln(14000) as decimal(2,3)) c1;
+ 
 #
 # Bug #8449 (Silent column changes)
 #

sql/item_create.cc

@@ -450,6 +450,7 @@ Item *create_func_cast(Item *a, Cast_target cast_type, int len, int dec,
 		       CHARSET_INFO *cs)
 {
   Item *res;
+  int tmp_len;
   LINT_INIT(res);
 
   switch (cast_type) {
@@ -460,7 +461,13 @@ Item *create_func_cast(Item *a, Cast_target cast_type, int len, int dec,
   case ITEM_CAST_TIME:		res= new Item_time_typecast(a); break;
   case ITEM_CAST_DATETIME:	res= new Item_datetime_typecast(a); break;
   case ITEM_CAST_DECIMAL:
-    res= new Item_decimal_typecast(a, (len>0) ? len : 10, dec ? dec : 2);
+    tmp_len= (len>0) ? len : 10;
+    if (tmp_len < dec)
+    {
+      my_error(ER_M_BIGGER_THAN_D, MYF(0), "");
+      return 0;
+    }
+    res= new Item_decimal_typecast(a, tmp_len, dec ? dec : 2);
     break;
   case ITEM_CAST_CHAR:
     res= new Item_char_typecast(a, len, cs ? cs : 

sql/sql_yacc.yy

@@ -4359,6 +4359,8 @@ simple_expr:
                                  lex->length ? atoi(lex->length) : -1,
                                  lex->dec ? atoi(lex->dec) : 0,
                                  lex->charset);
+            if (!$$)
+              YYABORT;
 	  }
 	| CASE_SYM opt_expr WHEN_SYM when_list opt_else END
 	  { $$= new Item_func_case(* $4, $2, $5 ); }
@@ -4368,6 +4370,8 @@ simple_expr:
 				 Lex->length ? atoi(Lex->length) : -1,
                                  Lex->dec ? atoi(Lex->dec) : 0,
 				 Lex->charset);
+            if (!$$)
+              YYABORT;
 	  }
 	| CONVERT_SYM '(' expr USING charset_name ')'
 	  { $$= new Item_func_conv_charset($3,$5); }