Allow referring to functions without arguments when unique

In DDL commands referring to an existing function, allow omitting the
argument list if the function name is unique in its schema, per SQL
standard.

This uses the same logic that the regproc type uses for finding
functions by name only.

Reviewed-by: Michael Paquier 

diff --git a/doc/src/sgml/ref/alter_extension.sgml b/doc/src/sgml/ref/alter_extension.sgml
index de6d6dca16b054e50c66a1e955958eb5c7b14331..a7c0927d1c9ebc5944894191052a088f13a4305a 100644 (file)
--- a/doc/src/sgml/ref/alter_extension.sgml
+++ b/doc/src/sgml/ref/alter_extension.sgml
@@ -39,7 +39,7 @@ ALTER EXTENSION name DROP 
   EVENT TRIGGER object_name |
   FOREIGN DATA WRAPPER object_name |
   FOREIGN TABLE object_name |
-  FUNCTION function_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |
+  FUNCTION function_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |
   MATERIALIZED VIEW object_name |
   OPERATOR operator_name (left_type, right_type) |
   OPERATOR CLASS object_name USING index_method |

diff --git a/doc/src/sgml/ref/alter_function.sgml b/doc/src/sgml/ref/alter_function.sgml
index 0388d06b959d91bca7cfaedea958174b239f5ed0..168eeb7c526029bcb3b3dd35eaea281d91ceb12b 100644 (file)
--- a/doc/src/sgml/ref/alter_function.sgml
+++ b/doc/src/sgml/ref/alter_function.sgml
@@ -21,15 +21,15 @@ PostgreSQL documentation
 
  
 
-ALTER FUNCTION name ( [ [ argmode ] [ argname ] argtype [, ...] ] )
+ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
     action [ ... ] [ RESTRICT ]
-ALTER FUNCTION name ( [ [ argmode ] [ argname ] argtype [, ...] ] )
+ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
     RENAME TO new_name
-ALTER FUNCTION name ( [ [ argmode ] [ argname ] argtype [, ...] ] )
+ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
     OWNER TO { new_owner | CURRENT_USER | SESSION_USER }
-ALTER FUNCTION name ( [ [ argmode ] [ argname ] argtype [, ...] ] )
+ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
     SET SCHEMA new_schema
-ALTER FUNCTION name ( [ [ argmode ] [ argname ] argtype [, ...] ] )
+ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
     DEPENDS ON EXTENSION extension_name
 
 where action is one of:
@@ -75,7 +75,8 @@ ALTER FUNCTION name ( [ [ 
     name
     
      
-      The name (optionally schema-qualified) of an existing function.
+      The name (optionally schema-qualified) of an existing function.  If no
+      argument list is specified, the name must be unique in its schema.
      
     
    

diff --git a/doc/src/sgml/ref/alter_opfamily.sgml b/doc/src/sgml/ref/alter_opfamily.sgml
index 4511c7f7b24c9cc5865150dceca28dda648259c0..0bafe5b8f807652d3a48ba0c906a01b887c8810d 100644 (file)
--- a/doc/src/sgml/ref/alter_opfamily.sgml
+++ b/doc/src/sgml/ref/alter_opfamily.sgml
@@ -25,7 +25,7 @@ ALTER OPERATOR FAMILY name USING 
   {  OPERATOR strategy_number operator_name ( op_type, op_type )
               [ FOR SEARCH | FOR ORDER BY sort_family_name ]
    | FUNCTION support_number [ ( op_type [ , op_type ] ) ]
-              function_name ( argument_type [, ...] )
+              function_name [ ( argument_type [, ...] ) ]
   } [, ... ]
 
 ALTER OPERATOR FAMILY name USING index_method DROP
@@ -195,8 +195,9 @@ ALTER OPERATOR FAMILY name USING 
     function_name
     
      
-      The name (optionally schema-qualified) of a function that is an
-      index method support procedure for the operator family.
+      The name (optionally schema-qualified) of a function that is an index
+      method support procedure for the operator family.  If no argument list
+      is specified, the name must be unique in its schema.
      
     
    

diff --git a/doc/src/sgml/ref/comment.sgml b/doc/src/sgml/ref/comment.sgml
index c1cf587cb29477c3941fdb3d3a8435a007fc905a..7483c8c03fce741dc699c0de1d86ea6d8e05f607 100644 (file)
--- a/doc/src/sgml/ref/comment.sgml
+++ b/doc/src/sgml/ref/comment.sgml
@@ -37,7 +37,7 @@ COMMENT ON
   EVENT TRIGGER object_name |
   FOREIGN DATA WRAPPER object_name |
   FOREIGN TABLE object_name |
-  FUNCTION function_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |
+  FUNCTION function_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |
   INDEX object_name |
   LARGE OBJECT large_object_oid |
   MATERIALIZED VIEW object_name |

diff --git a/doc/src/sgml/ref/create_cast.sgml b/doc/src/sgml/ref/create_cast.sgml
index 11266755e56ea9f9537a2abd52a520731e388684..a7d13edc22b1d86a2fc8a90361f25215c2caf02f 100644 (file)
--- a/doc/src/sgml/ref/create_cast.sgml
+++ b/doc/src/sgml/ref/create_cast.sgml
@@ -19,7 +19,7 @@
  
 
 CREATE CAST (source_type AS target_type)
-    WITH FUNCTION function_name (argument_type [, ...])
+    WITH FUNCTION function_name [ (argument_type [, ...]) ]
     [ AS ASSIGNMENT | AS IMPLICIT ]
 
 CREATE CAST (source_type AS target_type)
@@ -192,7 +192,7 @@ SELECT CAST ( 2 AS numeric ) + 4.0;
     
 
     
-     <replaceable>function_name(argument_type [, ...])
+     <literal>function_name[(argument_type [, ...])]
 
      
       
@@ -200,6 +200,8 @@ SELECT CAST ( 2 AS numeric ) + 4.0;
        be schema-qualified.  If it is not, the function will be looked
        up in the schema search path.  The function's result data type must
        match the target type of the cast.   Its arguments are discussed below.
+       If no argument list is specified, the function name must be unique in
+       its schema.
       
      
     

diff --git a/doc/src/sgml/ref/create_transform.sgml b/doc/src/sgml/ref/create_transform.sgml
index f44ee89d33c9e76e59afba20560be52d273cf45a..647c3b9f0571c45a793caf672e748547350df236 100644 (file)
--- a/doc/src/sgml/ref/create_transform.sgml
+++ b/doc/src/sgml/ref/create_transform.sgml
@@ -19,8 +19,8 @@
  
 
 CREATE [ OR REPLACE ] TRANSFORM FOR type_name LANGUAGE lang_name (
-    FROM SQL WITH FUNCTION from_sql_function_name (argument_type [, ...]),
-    TO SQL WITH FUNCTION to_sql_function_name (argument_type [, ...])
+    FROM SQL WITH FUNCTION from_sql_function_name [ (argument_type [, ...]) ],
+    TO SQL WITH FUNCTION to_sql_function_name [ (argument_type [, ...]) ]
 );
 
  
@@ -104,7 +104,7 @@ CREATE [ OR REPLACE ] TRANSFORM FOR type_name LANGUAG
     
 
     
-     <replaceable>from_sql_function_name(argument_type [, ...])
+     <literal>from_sql_function_name[(argument_type [, ...])]
 
      
       
@@ -116,12 +116,14 @@ CREATE [ OR REPLACE ] TRANSFORM FOR type_name LANGUAG
        SQL-level function returning internal without at
        least one argument of type internal.)  The actual return
        value will be something specific to the language implementation.
+       If no argument list is specified, the function name must be unique in
+       its schema.
       
      
     
 
     
-     <replaceable>to_sql_function_name(argument_type [, ...])
+     <literal>to_sql_function_name[(argument_type [, ...])]
 
      
       
@@ -130,6 +132,8 @@ CREATE [ OR REPLACE ] TRANSFORM FOR type_name LANGUAG
        internal and return the type that is the type for the
        transform.  The actual argument value will be something specific to the
        language implementation.
+       If no argument list is specified, the function name must be unique in
+       its schema.
       
      
     

diff --git a/doc/src/sgml/ref/drop_function.sgml b/doc/src/sgml/ref/drop_function.sgml
index 5969b084b44c485abe8fb7f76d908f43baa52576..0aa984528d32f48ccf8cfdcd4e967a4876030231 100644 (file)
--- a/doc/src/sgml/ref/drop_function.sgml
+++ b/doc/src/sgml/ref/drop_function.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  
 
-DROP FUNCTION [ IF EXISTS ] name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) [, ...]
+DROP FUNCTION [ IF EXISTS ] name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] [, ...]
     [ CASCADE | RESTRICT ]
 
  
@@ -56,7 +56,8 @@ DROP FUNCTION [ IF EXISTS ] name (
     name
     
      
-      The name (optionally schema-qualified) of an existing function.
+      The name (optionally schema-qualified) of an existing function.  If no
+      argument list is specified, the name must be unique in its schema.
      
     
    
@@ -141,14 +142,40 @@ DROP FUNCTION sqrt(integer);
 
 DROP FUNCTION sqrt(integer), sqrt(bigint);
 
+
+  
+   If the function name is unique in its schema, it can be referred to without
+   an argument list:
+
+DROP FUNCTION update_employee_salaries;
+
+   Note that this is different from
+
+DROP FUNCTION update_employee_salaries();
+
+   which refers to a function with zero arguments, whereas the first variant
+   can refer to a function with any number of arguments, including zero, as
+   long as the name is unique.
+  
  
 
  
   Compatibility
 
   
-   A DROP FUNCTION statement is defined in the SQL
-   standard, but it is not compatible with this command.
+   This command conforms to the SQL standard, with
+   these PostgreSQL extensions:
+   
+    
+     The standard only allows one function to be dropped per command.
+    
+    
+     The IF EXISTS option
+    
+    
+     The ability to specify argument modes and names
+    
+   
   
  
 

diff --git a/doc/src/sgml/ref/grant.sgml b/doc/src/sgml/ref/grant.sgml
index d8ca39f869e4c4c85fdf460bb9e068fcf2cd6b94..9fb4c2fd7e3aafa32131d8ee81c191bc2125c0ec 100644 (file)
--- a/doc/src/sgml/ref/grant.sgml
+++ b/doc/src/sgml/ref/grant.sgml
@@ -55,7 +55,7 @@ GRANT { USAGE | ALL [ PRIVILEGES ] }
     TO role_specification [, ...] [ WITH GRANT OPTION ]
 
 GRANT { EXECUTE | ALL [ PRIVILEGES ] }
-    ON { FUNCTION function_name ( [ [ argmode ] [ arg_name ] arg_type [, ...] ] ) [, ...]
+    ON { FUNCTION function_name [ ( [ [ argmode ] [ arg_name ] arg_type [, ...] ] ) ] [, ...]
          | ALL FUNCTIONS IN SCHEMA schema_name [, ...] }
     TO role_specification [, ...] [ WITH GRANT OPTION ]
 

diff --git a/doc/src/sgml/ref/revoke.sgml b/doc/src/sgml/ref/revoke.sgml
index fc00129620b626036274bc5e11b7558a1152da7b..ce532543f0b8ff775564842daa8dfac8a8a2b578 100644 (file)
--- a/doc/src/sgml/ref/revoke.sgml
+++ b/doc/src/sgml/ref/revoke.sgml
@@ -70,7 +70,7 @@ REVOKE [ GRANT OPTION FOR ]
 
 REVOKE [ GRANT OPTION FOR ]
     { EXECUTE | ALL [ PRIVILEGES ] }
-    ON { FUNCTION function_name ( [ [ argmode ] [ arg_name ] arg_type [, ...] ] ) [, ...]
+    ON { FUNCTION function_name [ ( [ [ argmode ] [ arg_name ] arg_type [, ...] ] ) ] [, ...]
          | ALL FUNCTIONS IN SCHEMA schema_name [, ...] }
     FROM { [ GROUP ] role_name | PUBLIC } [, ...]
     [ CASCADE | RESTRICT ]

diff --git a/doc/src/sgml/ref/security_label.sgml b/doc/src/sgml/ref/security_label.sgml
index 998fe3b7c03dadfd7867eda946e044108957d987..afd86aff3a01eefed82f1d091c5e271782ac5640 100644 (file)
--- a/doc/src/sgml/ref/security_label.sgml
+++ b/doc/src/sgml/ref/security_label.sgml
@@ -30,7 +30,7 @@ SECURITY LABEL [ FOR provider ] ON
   DOMAIN object_name |
   EVENT TRIGGER object_name |
   FOREIGN TABLE object_name
-  FUNCTION function_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |
+  FUNCTION function_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |
   LARGE OBJECT large_object_oid |
   MATERIALIZED VIEW object_name |
   [ PROCEDURAL ] LANGUAGE object_name |

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index bfc2ac1716510ed6537fd4e378565376945931a3..25fd051d6ef7324101df090e39b78ddb9ae8a111 100644 (file)
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -3067,6 +3067,7 @@ _copyObjectWithArgs(const ObjectWithArgs *from)
 
    COPY_NODE_FIELD(objname);
    COPY_NODE_FIELD(objargs);
+   COPY_SCALAR_FIELD(args_unspecified);
 
    return newnode;
 }

diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 54e9c983a0f416f66f6db5ffcb392440706d9294..67529e3f861f23d0e01d8407ceaef2fe5e94f0d8 100644 (file)
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1119,6 +1119,7 @@ _equalObjectWithArgs(const ObjectWithArgs *a, const ObjectWithArgs *b)
 {
    COMPARE_NODE_FIELD(objname);
    COMPARE_NODE_FIELD(objargs);
+   COMPARE_SCALAR_FIELD(args_unspecified);
 
    return true;
 }

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index e7acc2d9a2304943d83939d05d99b5dbdbf979a2..6316688a8835c898db4e4bda23b7cf53255544cd 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -7202,6 +7202,33 @@ function_with_argtypes:
                    n->objargs = extractArgTypes($2);
                    $$ = n;
                }
+           /*
+            * Because of reduce/reduce conflicts, we can't use func_name
+            * below, but we can write it out the long way, which actually
+            * allows more cases.
+            */
+           | type_func_name_keyword
+               {
+                   ObjectWithArgs *n = makeNode(ObjectWithArgs);
+                   n->objname = list_make1(makeString(pstrdup($1)));
+                   n->args_unspecified = true;
+                   $$ = n;
+               }
+           | ColId
+               {
+                   ObjectWithArgs *n = makeNode(ObjectWithArgs);
+                   n->objname = list_make1(makeString($1));
+                   n->args_unspecified = true;
+                   $$ = n;
+               }
+           | ColId indirection
+               {
+                   ObjectWithArgs *n = makeNode(ObjectWithArgs);
+                   n->objname = check_func_name(lcons(makeString($1), $2),
+                                                 yyscanner);
+                   n->args_unspecified = true;
+                   $$ = n;
+               }
        ;
 
 /*

diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index dd9749f205656266638b5501ef2dc206cd8b78e5..55853c20bb49345ca2c89f85a89d7d2bd958748b 100644 (file)
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -1895,8 +1895,10 @@ func_signature_string(List *funcname, int nargs,
 
 /*
  * LookupFuncName
- *     Given a possibly-qualified function name and a set of argument types,
- *     look up the function.
+ *
+ * Given a possibly-qualified function name and optionally a set of argument
+ * types, look up the function.  Pass nargs == -1 to indicate that no argument
+ * types are specified.
  *
  * If the function name is not schema-qualified, it is sought in the current
  * namespace search path.
@@ -1914,6 +1916,35 @@ LookupFuncName(List *funcname, int nargs, const Oid *argtypes, bool noError)
 
    clist = FuncnameGetCandidates(funcname, nargs, NIL, false, false, noError);
 
+   /*
+    * If no arguments were specified, the name must yield a unique candidate.
+    */
+   if (nargs == -1)
+   {
+       if (clist)
+       {
+           if (clist->next)
+           {
+               if (!noError)
+                   ereport(ERROR,
+                           (errcode(ERRCODE_AMBIGUOUS_FUNCTION),
+                            errmsg("function name \"%s\" is not unique",
+                                   NameListToString(funcname)),
+                            errhint("Specify the argument list to select the function unambiguously.")));
+           }
+           else
+               return clist->oid;
+       }
+       else
+       {
+           if (!noError)
+               ereport(ERROR,
+                       (errcode(ERRCODE_UNDEFINED_FUNCTION),
+                        errmsg("could not find a function named \"%s\"",
+                               NameListToString(funcname))));
+       }
+   }
+
    while (clist)
    {
        if (memcmp(argtypes, clist->args, nargs * sizeof(Oid)) == 0)
@@ -1962,7 +1993,7 @@ LookupFuncWithArgs(ObjectWithArgs *func, bool noError)
        args_item = lnext(args_item);
    }
 
-   return LookupFuncName(func->objname, argcount, argoids, noError);
+   return LookupFuncName(func->objname, func->args_unspecified ? -1 : argcount, argoids, noError);
 }
 
 /*

diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index a44d2178e1cbda9e05dab4fb4144435cc019f064..d576523f6a82676b7bd71ca1ce0c593167ed8211 100644 (file)
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1811,6 +1811,9 @@ typedef struct ObjectWithArgs
    NodeTag     type;
    List       *objname;        /* qualified name of function/operator */
    List       *objargs;        /* list of Typename nodes */
+   bool        args_unspecified; /* argument list was omitted, so name must
+                                  * be unique (note that objargs == NIL means
+                                  * zero args) */
 } ObjectWithArgs;
 
 /*

diff --git a/src/test/regress/expected/create_function_3.out b/src/test/regress/expected/create_function_3.out
index cc4e98a1d4b77144df09247ff53e24a8786db6f7..b5e19485e56e769394be7356419599f046df62f2 100644 (file)
--- a/src/test/regress/expected/create_function_3.out
+++ b/src/test/regress/expected/create_function_3.out
@@ -218,13 +218,21 @@ SELECT routine_name, ordinal_position, parameter_name, parameter_default
 (7 rows)
 
 DROP FUNCTION functest_IS_1(int, int, text), functest_IS_2(int), functest_IS_3(int);
+-- overload
+CREATE FUNCTION functest_B_2(bigint) RETURNS bool LANGUAGE 'sql'
+       IMMUTABLE AS 'SELECT $1 > 0';
+DROP FUNCTION functest_b_1;
+DROP FUNCTION functest_b_1;  -- error, not found
+ERROR:  could not find a function named "functest_b_1"
+DROP FUNCTION functest_b_2;  -- error, ambiguous
+ERROR:  function name "functest_b_2" is not unique
+HINT:  Specify the argument list to select the function unambiguously.
 -- Cleanups
 DROP SCHEMA temp_func_test CASCADE;
 NOTICE:  drop cascades to 16 other objects
 DETAIL:  drop cascades to function functest_a_1(text,date)
 drop cascades to function functest_a_2(text[])
 drop cascades to function functest_a_3()
-drop cascades to function functest_b_1(integer)
 drop cascades to function functest_b_2(integer)
 drop cascades to function functest_b_3(integer)
 drop cascades to function functest_b_4(integer)
@@ -237,5 +245,6 @@ drop cascades to function functext_f_1(integer)
 drop cascades to function functext_f_2(integer)
 drop cascades to function functext_f_3(integer)
 drop cascades to function functext_f_4(integer)
+drop cascades to function functest_b_2(bigint)
 DROP USER regress_unpriv_user;
 RESET search_path;

diff --git a/src/test/regress/sql/create_function_3.sql b/src/test/regress/sql/create_function_3.sql
index 66a463b08951db9a6cad4567fe813e4f17c0b390..0a0e407aaba692948798d46b168e647e24ab36a3 100644 (file)
--- a/src/test/regress/sql/create_function_3.sql
+++ b/src/test/regress/sql/create_function_3.sql
@@ -158,6 +158,14 @@ SELECT routine_name, ordinal_position, parameter_name, parameter_default
 
 DROP FUNCTION functest_IS_1(int, int, text), functest_IS_2(int), functest_IS_3(int);
 
+-- overload
+CREATE FUNCTION functest_B_2(bigint) RETURNS bool LANGUAGE 'sql'
+       IMMUTABLE AS 'SELECT $1 > 0';
+
+DROP FUNCTION functest_b_1;
+DROP FUNCTION functest_b_1;  -- error, not found
+DROP FUNCTION functest_b_2;  -- error, ambiguous
+
 
 -- Cleanups
 DROP SCHEMA temp_func_test CASCADE;