Bug#28318 (CREATE FUNCTION (UDF) requires a schema) -- part II

The root cause of the issue was that the CREATE FUNCTION grammar,
for User Defined Functions, was using the sp_name rule.
The sp_name rule is intended for fully qualified stored procedure names,
like either ident.ident, or just ident but with a default database
implicitly selected.

A UDF does not have a fully qualified name, only a name (ident), and should
not use the sp_name grammar fragment during parsing.

The fix is to re-organize the CREATE FUNCTION grammar, to better separate:
- creating UDF (no definer, can have AGGREGATE, simple ident)
- creating Stored Functions (definer, no AGGREGATE, fully qualified name)

With the test case provided, another issue was exposed which is also fixed:
the DROP FUNCTION statement was using sp_name and also failing when no database
is implicitly selected, when droping UDF functions.
The fix is also to change the grammar so that DROP FUNCTION works with
both the ident.ident syntax (to drop a stored function), or just the ident
syntax (to drop either a UDF or a Stored Function, in the current database)

mysql-test/r/sp-error.result

@@ -1211,7 +1211,7 @@ ERROR 42S02: Unknown table 'c' in field list
 drop procedure bug15091;
 drop function if exists bug16896;
 create aggregate function bug16896() returns int return 1;
-ERROR 42000: AGGREGATE is not supported for stored functions
+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 '() returns int return 1' at line 1
 DROP PROCEDURE IF EXISTS bug14702;
 CREATE IF NOT EXISTS PROCEDURE bug14702()
 BEGIN
@@ -1457,7 +1457,7 @@ CREATE DATABASE mysqltest;
 USE mysqltest;
 DROP DATABASE mysqltest;
 SELECT inexistent(), 1 + ,;
-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 '' at line 1
+ERROR 42000: FUNCTION inexistent does not exist
 SELECT inexistent();
 ERROR 42000: FUNCTION inexistent does not exist
 SELECT .inexistent();

mysql-test/r/udf.result

@@ -95,10 +95,10 @@ FR
 DROP TABLE bug19904;
 CREATE DEFINER=CURRENT_USER() FUNCTION should_not_parse
 RETURNS STRING SONAME "should_not_parse.so";
-ERROR HY000: Incorrect usage of SONAME and DEFINER
+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 'RETURNS STRING SONAME "should_not_parse.so"' at line 2
 CREATE DEFINER=someone@somewhere FUNCTION should_not_parse
 RETURNS STRING SONAME "should_not_parse.so";
-ERROR HY000: Incorrect usage of SONAME and DEFINER
+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 'RETURNS STRING SONAME "should_not_parse.so"' at line 2
 create table t1(f1 int);
 insert into t1 values(1),(2);
 explain select myfunc_int(f1) from t1 order by 1;

mysql-test/t/sp-error.test

@@ -1744,7 +1744,7 @@ drop procedure bug15091;
 drop function if exists bug16896;
 --enable_warnings
 
---error ER_SP_NO_AGGREGATE
+--error ER_PARSE_ERROR
 create aggregate function bug16896() returns int return 1;
 
 
@@ -2099,7 +2099,10 @@ DROP DATABASE IF EXISTS mysqltest;
 CREATE DATABASE mysqltest;
 USE mysqltest;
 DROP DATABASE mysqltest;
---error ER_PARSE_ERROR
+# Both ER_SP_DOES_NOT_EXIST and ER_PARSE_ERROR are valid here,
+# the result is implementation dependent:
+# See Bug#29816 for details
+--error ER_SP_DOES_NOT_EXIST
 SELECT inexistent(), 1 + ,;
 --error ER_SP_DOES_NOT_EXIST
 SELECT inexistent();

mysql-test/t/udf.test

@@ -113,11 +113,11 @@ DROP TABLE bug19904;
 # Bug#21269: DEFINER-clause is allowed for UDF-functions
 #
 
---error ER_WRONG_USAGE
+--error ER_PARSE_ERROR
 CREATE DEFINER=CURRENT_USER() FUNCTION should_not_parse
 RETURNS STRING SONAME "should_not_parse.so";
 
---error ER_WRONG_USAGE
+--error ER_PARSE_ERROR
 CREATE DEFINER=someone@somewhere FUNCTION should_not_parse
 RETURNS STRING SONAME "should_not_parse.so";
 #

sql/sql_parse.cc

@@ -4016,12 +4016,6 @@ end_with_restore_list:
     if (check_access(thd,INSERT_ACL,"mysql",0,1,0,0))
       break;
 #ifdef HAVE_DLOPEN
-    if (sp_find_routine(thd, TYPE_ENUM_FUNCTION, lex->spname,
-                        &thd->sp_func_cache, FALSE))
-    {
-      my_error(ER_UDF_EXISTS, MYF(0), lex->spname->m_name.str);
-      goto error;
-    }
     if (!(res = mysql_create_function(thd, &lex->udf)))
       send_ok(thd);
 #else

sql/sql_yacc.yy

@@ -1121,8 +1121,6 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 
 %type <cast_type> cast_type
 
-%type <udf_type> udf_func_type
-
 %type <symbol> FUNC_ARG0 FUNC_ARG1 FUNC_ARG2 FUNC_ARG3 keyword keyword_sp
 
 %type <lex_user> user grant_user
@@ -1181,11 +1179,12 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 	statement sp_suid
 	sp_c_chistics sp_a_chistics sp_chistic sp_c_chistic xa
         load_data opt_field_or_var_spec fields_or_vars opt_load_data_set_spec
-        definer view_replace_or_algorithm view_replace view_algorithm_opt
-        view_algorithm view_or_trigger_or_sp view_or_trigger_or_sp_tail
+        view_replace_or_algorithm view_replace view_algorithm_opt
+        view_algorithm view_or_trigger_or_sp definer_tail
 	view_suid view_tail view_list_opt view_list view_select
-	view_check_option trigger_tail sp_tail
+	view_check_option trigger_tail sp_tail sf_tail udf_tail
         case_stmt_specification simple_case_stmt searched_case_stmt
+        definer_opt no_definer definer
 END_OF_INPUT
 
 %type <NONE> call sp_proc_stmts sp_proc_stmts1 sp_proc_stmt
@@ -1570,15 +1569,14 @@ sp_name:
 	| ident
 	  {
             LEX *lex= Lex;
-            LEX_STRING db= {0,0};
-            THD *thd= YYTHD;
+            LEX_STRING db;
 
 	    if (check_routine_name($1))
             {
 	      my_error(ER_SP_WRONG_NAME, MYF(0), $1.str);
 	      MYSQL_YYABORT;
 	    }
-            if (thd->db && thd->copy_db_to(&db.str, &db.length))
+            if (lex->copy_db_to(&db.str, &db.length))
               MYSQL_YYABORT;
 	    $$= new sp_name(db, $1, false);
             if ($$)
@@ -1586,131 +1584,6 @@ sp_name:
 	  }
 	;
 
-create_function_tail:
-	  RETURNS_SYM udf_type UDF_SONAME_SYM TEXT_STRING_sys
-	  {
-	    LEX *lex=Lex;
-            if (lex->definer != NULL)
-            {
-              /*
-                 DEFINER is a concept meaningful when interpreting SQL code.
-                 UDF functions are compiled.
-                 Using DEFINER with UDF has therefore no semantic,
-                 and is considered a parsing error.
-              */
-	      my_error(ER_WRONG_USAGE, MYF(0), "SONAME", "DEFINER");
-              MYSQL_YYABORT;
-            }
-	    lex->sql_command = SQLCOM_CREATE_FUNCTION;
-	    lex->udf.name = lex->spname->m_name;
-	    lex->udf.returns=(Item_result) $2;
-	    lex->udf.dl=$4.str;
-	  }
-	| '('
-	  {
-            THD *thd= YYTHD;
-	    LEX *lex= thd->lex;
-            Lex_input_stream *lip= thd->m_lip;
-	    sp_head *sp;
-
-            /* 
-              First check if AGGREGATE was used, in that case it's a
-              syntax error.
-            */
-            if (lex->udf.type == UDFTYPE_AGGREGATE)
-            {
-              my_error(ER_SP_NO_AGGREGATE, MYF(0));
-              MYSQL_YYABORT;
-            }
-
-	    if (lex->sphead)
-	    {
-	      my_error(ER_SP_NO_RECURSIVE_CREATE, MYF(0), "FUNCTION");
-	      MYSQL_YYABORT;
-	    }
-
-            if (!lex->spname->m_db.length)
-            {
-              my_message(ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR), MYF(0));
-              MYSQL_YYABORT;
-            }
-
-	    /* Order is important here: new - reset - init */
-	    sp= new sp_head();
-	    sp->reset_thd_mem_root(thd);
-	    sp->init(lex);
-            sp->init_sp_name(thd, lex->spname);
-
-	    sp->m_type= TYPE_ENUM_FUNCTION;
-	    lex->sphead= sp;
-	    /*
-	     * We have to turn of CLIENT_MULTI_QUERIES while parsing a
-	     * stored procedure, otherwise yylex will chop it into pieces
-	     * at each ';'.
-	     */
-	    sp->m_old_cmq= thd->client_capabilities & CLIENT_MULTI_QUERIES;
-	    thd->client_capabilities &= ~CLIENT_MULTI_QUERIES;
-	    lex->sphead->m_param_begin= lip->tok_start+1;
-	  }
-          sp_fdparam_list ')'
-	  {
-            THD *thd= YYTHD;
-	    LEX *lex= thd->lex;
-            Lex_input_stream *lip= thd->m_lip;
-
-	    lex->sphead->m_param_end= lip->tok_start;
-	  }
-	  RETURNS_SYM
-	  {
-	    LEX *lex= Lex;
-	    lex->charset= NULL;
-	    lex->length= lex->dec= NULL;
-	    lex->interval_list.empty();
-	    lex->type= 0;
-	  }
-	  type
-	  {
-	    LEX *lex= Lex;
-	    sp_head *sp= lex->sphead;
-
-            if (sp->fill_field_definition(YYTHD, lex,
-                                          (enum enum_field_types) $8,
-                                          &sp->m_return_field_def))
-              MYSQL_YYABORT;
-
-	    bzero((char *)&lex->sp_chistics, sizeof(st_sp_chistics));
-	  }
-	  sp_c_chistics
-	  {
-            THD *thd= YYTHD;
-	    LEX *lex= thd->lex;
-            Lex_input_stream *lip= thd->m_lip;
-
-	    lex->sphead->m_chistics= &lex->sp_chistics;
-	    lex->sphead->m_body_begin= lip->tok_start;
-	  }
-	  sp_proc_stmt
-	  {
-	    LEX *lex= Lex;
-	    sp_head *sp= lex->sphead;
-
-            if (sp->is_not_allowed_in_function("function"))
-              MYSQL_YYABORT;
-
-	    lex->sql_command= SQLCOM_CREATE_SPFUNCTION;
-	    sp->init_strings(YYTHD, lex);
-            if (!(sp->m_flags & sp_head::HAS_RETURN))
-            {
-              my_error(ER_SP_NORETURN, MYF(0), sp->m_qname.str);
-              MYSQL_YYABORT;
-            }
-	    /* Restore flag if it was cleared above */
-	    if (sp->m_old_cmq)
-	      YYTHD->client_capabilities |= CLIENT_MULTI_QUERIES;
-	    sp->restore_thd_mem_root(YYTHD);
-	  }
-	;
-
 sp_a_chistics:
 	  /* Empty */ {}
 	| sp_a_chistics sp_chistic {}
@@ -3011,10 +2884,6 @@ opt_select_from:
 	opt_limit_clause {}
 	| select_from select_lock_type;
 
-udf_func_type:
-	/* empty */	{ $$ = UDFTYPE_FUNCTION; }
-	| AGGREGATE_SYM { $$ = UDFTYPE_AGGREGATE; };
-
 udf_type:
 	STRING_SYM {$$ = (int) STRING_RESULT; }
 	| REAL {$$ = (int) REAL_RESULT; }
@@ -3678,7 +3547,7 @@ alter:
 	    lex->sql_command= SQLCOM_ALTER_FUNCTION;
 	    lex->spname= $3;
 	  }
-        | ALTER view_algorithm_opt definer view_suid
+        | ALTER view_algorithm_opt definer_opt view_suid
           VIEW_SYM table_ident
 	  {
 	    THD *thd= YYTHD;
@@ -5204,9 +5073,31 @@ simple_expr:
 #endif /* HAVE_DLOPEN */
             {
               THD *thd= lex->thd;
-              LEX_STRING db= {0,0};
-              if (thd->db && thd->copy_db_to(&db.str, &db.length))
+              LEX_STRING db;
+              if (! thd->db && ! lex->sphead)
+              {
+                /*
+                  The proper error message should be in the lines of:
+                    Can't resolve <name>() to a function call,
+                    because this function:
+                    - is not a native function,
+                    - is not a user defined function,
+                    - can not match a stored function since no database is selected.
+                  Reusing ER_SP_DOES_NOT_EXIST have a message consistent with
+                  the case when a default database exist, see below.
+                */
+                my_error(ER_SP_DOES_NOT_EXIST, MYF(0),
+                         "FUNCTION", $1);
+                MYSQL_YYABORT;
+              }
+              
+              if (lex->copy_db_to(&db.str, &db.length))
                 MYSQL_YYABORT;
+
+              /*
+                From here, the parser assumes <name>() is a stored function,
+                as a last choice. This later can lead to ER_SP_DOES_NOT_EXIST.
+              */
               sp_name *name= new sp_name(db, $1, false);
               if (name)
                 name->init_qname(thd);
@@ -6508,9 +6399,11 @@ drop:
 	    lex->drop_if_exists=$3;
 	    lex->name=$4.str;
 	 }
-	| DROP FUNCTION_SYM if_exists sp_name
+	| DROP FUNCTION_SYM if_exists ident '.' ident
 	  {
-	    LEX *lex=Lex;
+            THD *thd= YYTHD;
+            LEX *lex= thd->lex;
+            sp_name *spname;
 	    if (lex->sphead)
 	    {
 	      my_error(ER_SP_NO_DROP_SP, MYF(0), "FUNCTION");
@@ -6518,7 +6411,28 @@ drop:
 	    }
 	    lex->sql_command = SQLCOM_DROP_FUNCTION;
 	    lex->drop_if_exists= $3;
-	    lex->spname= $4;
+	    spname= new sp_name($4, $6, true);
+	    spname->init_qname(thd);
+	    lex->spname= spname;
+	  }
+	| DROP FUNCTION_SYM if_exists ident
+	  {
+            THD *thd= YYTHD;
+            LEX *lex= thd->lex;
+            LEX_STRING db= {0, 0};
+            sp_name *spname;
+	    if (lex->sphead)
+	    {
+	      my_error(ER_SP_NO_DROP_SP, MYF(0), "FUNCTION");
+	      MYSQL_YYABORT;
+	    }
+            if (thd->db && lex->copy_db_to(&db.str, &db.length))
+              MYSQL_YYABORT;
+	    lex->sql_command = SQLCOM_DROP_FUNCTION;
+	    lex->drop_if_exists= $3;
+	    spname= new sp_name(db, $4, false);
+	    spname->init_qname(thd);
+	    lex->spname= spname;
 	  }
 	| DROP PROCEDURE if_exists sp_name
 	  {
@@ -9567,19 +9481,27 @@ subselect_end:
 **************************************************************************/
 
 view_or_trigger_or_sp:
-	definer view_or_trigger_or_sp_tail
+	  definer definer_tail
+	  {}
+	| no_definer no_definer_tail
 	  {}
-	| view_replace_or_algorithm definer view_tail
+	| view_replace_or_algorithm definer_opt view_tail
 	  {}
 	;
 
-view_or_trigger_or_sp_tail:
+definer_tail:
 	  view_tail
-	{}
 	| trigger_tail
-	{}
 	| sp_tail
-	{}
+	| sf_tail
+	;
+
+no_definer_tail:
+	  view_tail
+	| trigger_tail
+	| sp_tail
+	| sf_tail
+	| udf_tail
 	;
 
 /**************************************************************************
@@ -9588,7 +9510,12 @@ view_or_trigger_or_sp_tail:
 
 **************************************************************************/
 
-definer:
+definer_opt:
+          no_definer
+        | definer
+        ;
+
+no_definer:
           /* empty */
           {
             /*
@@ -9600,11 +9527,14 @@ definer:
              */
             YYTHD->lex->definer= 0;
           }
-	| DEFINER_SYM EQ user
+        ;
+
+definer:
+          DEFINER_SYM EQ user
           {
             YYTHD->lex->definer= get_current_user(YYTHD, $3);
           }
-	;
+;
 
 /**************************************************************************
 
@@ -9755,12 +9685,6 @@ trigger_tail:
 	    MYSQL_YYABORT;
 	  }
 
-	  if (!$3->m_db.length)
-	  {
-	    my_message(ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR), MYF(0));
-	    MYSQL_YYABORT;
-	  }
-
 	  if (!(sp= new sp_head()))
 	    MYSQL_YYABORT;
 	  sp->reset_thd_mem_root(thd);
@@ -9822,30 +9746,138 @@ trigger_tail:
 
 **************************************************************************/
 
-sp_tail:
-	udf_func_type remember_name FUNCTION_SYM sp_name
+udf_tail:
+          AGGREGATE_SYM remember_name FUNCTION_SYM ident
+	  RETURNS_SYM udf_type UDF_SONAME_SYM TEXT_STRING_sys
 	  {
 	    LEX *lex=Lex;
-	  lex->udf.type= $1;
+	    lex->sql_command = SQLCOM_CREATE_FUNCTION;
+	    lex->udf.type= UDFTYPE_AGGREGATE;
 	    lex->stmt_definition_begin= $2;
-	  lex->spname= $4;
+	    lex->udf.name = $4;
+	    lex->udf.returns=(Item_result) $6;
+	    lex->udf.dl=$8.str;
 	  }
-	create_function_tail
-	{}
-	| PROCEDURE remember_name sp_name
+        | remember_name FUNCTION_SYM ident
+	  RETURNS_SYM udf_type UDF_SONAME_SYM TEXT_STRING_sys
 	  {
-	  LEX *lex= Lex;
+	    LEX *lex=Lex;
+	    lex->sql_command = SQLCOM_CREATE_FUNCTION;
+	    lex->udf.type= UDFTYPE_FUNCTION;
+	    lex->stmt_definition_begin= $1;
+	    lex->udf.name = $3;
+	    lex->udf.returns=(Item_result) $5;
+	    lex->udf.dl=$7.str;
+	  }
+        ;
+
+sf_tail:
+          remember_name /* $1 */
+          FUNCTION_SYM /* $2 */
+          sp_name /* $3 */
+          '(' /* 44 */
+          { /* $5 */
+            THD *thd= YYTHD;
+	    LEX *lex= thd->lex;
+            Lex_input_stream *lip= thd->m_lip;
 	    sp_head *sp;
 
+	    lex->stmt_definition_begin= $1;
+	    lex->spname= $3;
+
 	    if (lex->sphead)
 	    {
-	    my_error(ER_SP_NO_RECURSIVE_CREATE, MYF(0), "PROCEDURE");
+	      my_error(ER_SP_NO_RECURSIVE_CREATE, MYF(0), "FUNCTION");
+	      MYSQL_YYABORT;
+	    }
+
+	    /* Order is important here: new - reset - init */
+	    sp= new sp_head();
+	    sp->reset_thd_mem_root(thd);
+	    sp->init(lex);
+            sp->init_sp_name(thd, lex->spname);
+
+	    sp->m_type= TYPE_ENUM_FUNCTION;
+	    lex->sphead= sp;
+	    /*
+	     * We have to turn of CLIENT_MULTI_QUERIES while parsing a
+	     * stored procedure, otherwise yylex will chop it into pieces
+	     * at each ';'.
+	     */
+	    sp->m_old_cmq= thd->client_capabilities & CLIENT_MULTI_QUERIES;
+	    thd->client_capabilities &= ~CLIENT_MULTI_QUERIES;
+	    lex->sphead->m_param_begin= lip->tok_start+1;
+	  }
+          sp_fdparam_list /* $6 */
+          ')' /* $7 */
+          { /* $8 */
+            THD *thd= YYTHD;
+	    LEX *lex= thd->lex;
+            Lex_input_stream *lip= thd->m_lip;
+
+	    lex->sphead->m_param_end= lip->tok_start;
+	  }
+          RETURNS_SYM /* $9 */
+	  { /* $10 */
+	    LEX *lex= Lex;
+	    lex->charset= NULL;
+	    lex->length= lex->dec= NULL;
+	    lex->interval_list.empty();
+	    lex->type= 0;
+	  }
+          type /* $11 */
+          { /* $12 */
+	    LEX *lex= Lex;
+	    sp_head *sp= lex->sphead;
+
+            if (sp->fill_field_definition(YYTHD, lex,
+                                          (enum enum_field_types) $11,
+                                          &sp->m_return_field_def))
+              MYSQL_YYABORT;
+
+	    bzero((char *)&lex->sp_chistics, sizeof(st_sp_chistics));
+	  }
+          sp_c_chistics /* $13 */
+          { /* $14 */
+            THD *thd= YYTHD;
+	    LEX *lex= thd->lex;
+            Lex_input_stream *lip= thd->m_lip;
+
+	    lex->sphead->m_chistics= &lex->sp_chistics;
+	    lex->sphead->m_body_begin= lip->tok_start;
+	  }
+          sp_proc_stmt /* $15 */
+	  {
+	    LEX *lex= Lex;
+	    sp_head *sp= lex->sphead;
+
+            if (sp->is_not_allowed_in_function("function"))
               MYSQL_YYABORT;
+
+	    lex->sql_command= SQLCOM_CREATE_SPFUNCTION;
+	    sp->init_strings(YYTHD, lex);
+            if (!(sp->m_flags & sp_head::HAS_RETURN))
+            {
+              my_error(ER_SP_NORETURN, MYF(0), sp->m_qname.str);
+              MYSQL_YYABORT;
+            }
+	    /* Restore flag if it was cleared above */
+	    if (sp->m_old_cmq)
+	      YYTHD->client_capabilities |= CLIENT_MULTI_QUERIES;
+	    sp->restore_thd_mem_root(YYTHD);
 	  }
+	;
+
 
-	  if (!$3->m_db.length)
+sp_tail:
+	PROCEDURE remember_name sp_name
 	{
-	    my_message(ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR), MYF(0));
+	  LEX *lex= Lex;
+	  sp_head *sp;
+
+	  if (lex->sphead)
+	  {
+	    my_error(ER_SP_NO_RECURSIVE_CREATE, MYF(0), "PROCEDURE");
 	    MYSQL_YYABORT;
 	  }