Bug#24736: UDF functions parsed as Stored Functions

Before this fix, a call to a User Defined Function (UDF) could,
under some circumstances, be interpreted as a call to a Stored function
instead. This occurred if a native function was invoked in the parameters
for the UDF, as in "select my_udf(abs(x))".

The root cause of this defect is the introduction, by the fix for Bug 21809,
of st_select_lex::udf_list, and it's usage in the parser in sql_yacc.yy
in the rule function_call_generic (in 5.1).

While the fix itself for Bug 21809 is correct in 5.0, the code change
merged into the 5.1 release created the issue, because the calls in 5.1 to :
- lex->current_select->udf_list.push_front(udf)
- lex->current_select->udf_list.pop()
are not balanced in case of native functions, causing the udf_list,
which is really a stack, to be out of sync with the internal stack
maintained by the bison parser.

Instead of moving the call to udf_list.pop(), which would have fixed the
symptom, this patch goes further and removes the need for udf_list.

This is motivated by two reasons:

a) Maintaining a stack in the MySQL code in sync with the stack maintained
internally in sql_yacc.cc (not .yy) is extremely dependent of the
implementation of yacc/bison, and extremely difficult to maintain.
It's also totally dependent of the structure of the grammar, and has a risk
to break with regression defects each time the grammar itself is changed.

b) The previous code did report construct like "foo(expr AS name)" as
syntax errors (ER_PARSER_ERROR), which is incorrect, and misleading.
The syntax is perfectly valid, as this expression is valid when "foo" is
a UDF. Whether this syntax is legal or not depends of the semantic of "foo".

With this change:

a) There is only one stack (in bison), and no List<udf_func> to maintain.

b) "foo(expr AS name)", when used incorrectly, is reported as semantic error:
- ER_WRONG_PARAMETERS_TO_NATIVE_FCT (for native functions)
- ER_WRONG_PARAMETERS_TO_STORED_FCT (for stored functions)
This is achieved by the changes implemented in item_create.cc


mysql-test/r/parser.result:
  New tests
mysql-test/r/udf.result:
  New tests
mysql-test/t/parser.test:
  New tests
mysql-test/t/udf.test:
  New tests
sql/item_create.cc:
  Semantic checks for named parameters, as in "foo(expr AS name)".
sql/share/errmsg.txt:
  New error message
sql/sql_lex.cc:
  Remove usage of udf_list.
sql/sql_lex.h:
  Remove usage of udf_list.
sql/sql_yacc.yy:
  Remove usage of udf_list.

1 files changed, 24 insertions, 2 deletions

diff --git a/mysql-test/r/udf.result b/mysql-test/r/udf.result
index 69c860d8f85..52c59e6feb0 100644
--- a/mysql-test/r/udf.result
+++ b/mysql-test/r/udf.result
@@ -132,9 +132,9 @@ a	c
 1	1
 2	2
 SELECT a, fn(MIN(b) xx) as c FROM t1 GROUP BY a;
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'xx) as c FROM t1 GROUP BY a' at line 1
+ERROR 42000: Incorrect parameters in the call to stored function 'fn'
 SELECT myfunc_int(fn(MIN(b) xx)) as c FROM t1 GROUP BY a;
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'xx)) as c FROM t1 GROUP BY a' at line 1
+ERROR 42000: Incorrect parameters in the call to stored function 'fn'
 SELECT myfunc_int(test.fn(MIN(b) xx)) as c FROM t1 GROUP BY a;
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'xx)) as c FROM t1 GROUP BY a' at line 1
 SELECT myfunc_int(fn(MIN(b)) xx) as c FROM t1 GROUP BY a;
@@ -185,6 +185,28 @@ DROP VIEW v1;
 DROP TABLE t1;
 DROP FUNCTION fn;
 End of 5.0 tests.
+select myfunc_double(3);
+myfunc_double(3)
+51.00
+select myfunc_double(3 AS three);
+myfunc_double(3 AS three)
+51.00
+select myfunc_double(abs(3));
+myfunc_double(abs(3))
+51.00
+select myfunc_double(abs(3) AS named_param);
+myfunc_double(abs(3) AS named_param)
+51.00
+select abs(myfunc_double(3));
+abs(myfunc_double(3))
+51.00
+select abs(myfunc_double(3 AS three));
+abs(myfunc_double(3 AS three))
+51.00
+select myfunc_double(abs(3 AS wrong));
+ERROR 42000: Incorrect parameters in the call to native function 'abs'
+select abs(myfunc_double(3) AS wrong);
+ERROR 42000: Incorrect parameters in the call to native function 'abs'
 DROP FUNCTION metaphon;
 DROP FUNCTION myfunc_double;
 DROP FUNCTION myfunc_nonexist;