Bug#18239 (Possible to overload internal functions with stored functions)

Bug#21025 (misleading error message when creating functions named 'x', or 'y')
Bug#22619 (Spaces considered harmful)

This change contains a fix to report warnings or errors, and multiple tests
cases.

Before this fix, name collisions between:
- Native functions
- User Defined Functions
- Stored Functions
were not systematically reported, leading to confusing behavior.

I) Native / User Defined Function

Before this fix, is was possible to create a UDF named "foo", with the same
name as a native function "foo", but it was impossible to invoke the UDF,
since the syntax "foo()" always refer to the native function.
After this fix, creating a UDF fails with an error if there is a name
collision with a native function.

II) Native / Stored Function

Before this fix, is was possible to create a SF named "db.foo", with the same
name as a native function "foo", but this was confusing since the syntax
"foo()" would refer to the native function. To refer to the Stored Function,
the user had to use the "db.foo()" syntax.
After this fix, creating a Stored Function reports a warning if there is a
name collision with a native function.

III) User Defined Function / Stored Function

Before this fix, creating a User Defined Function "foo" and a Stored Function
"db.foo" are mutually exclusive operations. Whenever the second function is
created, an error is reported. However, the test suite did not cover this
behavior.
After this fix, the  behavior is unchanged, and is now covered by test cases.

Note that the code change in this patch depends on the fix for Bug 21114.


mysql-test/r/sp.result:
  New test cases.
mysql-test/r/udf.result:
  New test cases.
mysql-test/t/sp.test:
  New test cases.
mysql-test/t/udf.test:
  New test cases.
sql/sql_lex.cc:
  Name collisions with native functions.
sql/sql_lex.h:
  Name collisions with native functions.
sql/sql_yacc.yy:
  Name collisions with native functions.
sql/share/errmsg.txt:
  Name collisions with native functions.
mysql-test/r/sp_gis.result:
  New test cases.
mysql-test/t/sp_gis.test:
  New test cases.

1 files changed, 106 insertions, 0 deletions

diff --git a/mysql-test/t/sp.test b/mysql-test/t/sp.test
index 7c1fd59c50b..d65c4cb526f 100644
--- a/mysql-test/t/sp.test
+++ b/mysql-test/t/sp.test
@@ -11,6 +11,7 @@
 # Tests that uses 'goto' to into sp-goto.test (currently disabled)
 # Tests that destroys system tables (e.g. mysql.proc) for error testing
 #   go to sp-destruct.
+# Tests that require --with-geometry go into sp_gis.test
 
 use test;
 
@@ -2584,6 +2585,9 @@ begin
   end if;
 end|
 
+# so that from_unixtime() has a deterministic result
+set time_zone='+03:00';
+
 call bug3426(1000, @i)|
 select @i, from_unixtime(@stamped_time, '%d-%m-%Y %h:%i:%s') as time|
 call bug3426(NULL, @i)|
@@ -6585,6 +6589,108 @@ drop procedure proc_21462_b|
 
 --echo End of 5.0 tests
 
+--echo Begin of 5.1 tests
+
+#
+# BUG#18239: Possible to overload internal functions with stored functions
+#
+
+delimiter ;|
+
+--disable_warnings
+drop function if exists pi;
+--enable_warnings
+
+create function pi() returns varchar(50)
+return "pie, my favorite desert.";
+
+SET @save_sql_mode=@@sql_mode;
+
+SET SQL_MODE='IGNORE_SPACE';
+
+select pi(), pi ();
+select test.pi(), test.pi ();
+
+SET SQL_MODE='';
+
+select pi(), pi ();
+select test.pi(), test.pi ();
+
+SET @@sql_mode=@save_sql_mode;
+
+drop function pi;
+# End of BUG#18239
+
+#
+# BUG#22619: Spaces considered harmful
+#
+
+--disable_warnings
+drop function if exists test.database;
+drop function if exists test.current_user;
+drop function if exists test.md5;
+--enable_warnings
+
+create database nowhere;
+use nowhere;
+drop database nowhere;
+
+SET @save_sql_mode=@@sql_mode;
+
+SET SQL_MODE='IGNORE_SPACE';
+
+select database(), database ();
+select current_user(), current_user ();
+select md5("aaa"), md5 ("aaa");
+
+SET SQL_MODE='';
+
+select database(), database ();
+select current_user(), current_user ();
+select md5("aaa"), md5 ("aaa");
+
+use test;
+
+create function `database`() returns varchar(50)
+return "Stored function database";
+
+create function `current_user`() returns varchar(50)
+return "Stored function current_user";
+
+create function md5(x varchar(50)) returns varchar(50)
+return "Stored function md5";
+
+SET SQL_MODE='IGNORE_SPACE';
+
+select database(), database ();
+select current_user(), current_user ();
+select md5("aaa"), md5 ("aaa");
+
+select test.database(), test.database ();
+select test.current_user(), test.current_user ();
+select test.md5("aaa"), test.md5 ("aaa");
+
+SET SQL_MODE='';
+
+select database(), database ();
+select current_user(), current_user ();
+select md5("aaa"), md5 ("aaa");
+
+select test.database(), test.database ();
+select test.current_user(), test.current_user ();
+select test.md5("aaa"), test.md5 ("aaa");
+
+SET @@sql_mode=@save_sql_mode;
+
+drop function test.database;
+drop function test.current_user;
+drop function md5;
+
+use test;
+delimiter |;
+# End of BUG#22619
+
+--echo End of 5.1 tests
 
 #
 # BUG#NNNN: New bug synopsis