Support for OUT parameters in procedures

Unlike for functions, OUT parameters for procedures are part of the
signature.  Therefore, they have to be listed in pg_proc.proargtypes
as well as mentioned in ALTER PROCEDURE and DROP PROCEDURE.

Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/2b8490fe-51af-e671-c504-47359dc453c5@2ndquadrant.com

5 files changed, 109 insertions, 60 deletions

diff --git a/src/backend/catalog/pg_proc.c b/src/backend/catalog/pg_proc.c
index 40d65dc6bab..f7dab9925b9 100644
--- a/src/backend/catalog/pg_proc.c
+++ b/src/backend/catalog/pg_proc.c
@@ -249,6 +249,9 @@ ProcedureCreate(const char *procedureName,
 						elog(ERROR, "variadic parameter must be last");
 					break;
 				case PROARGMODE_OUT:
+					if (OidIsValid(variadicType) && prokind == PROKIND_PROCEDURE)
+						elog(ERROR, "variadic parameter must be last");
+					break;
 				case PROARGMODE_TABLE:
 					/* okay */
 					break;
@@ -462,10 +465,12 @@ ProcedureCreate(const char *procedureName,
 			if (isnull)
 				proargmodes = PointerGetDatum(NULL);	/* just to be sure */
 
-			n_old_arg_names = get_func_input_arg_names(proargnames,
+			n_old_arg_names = get_func_input_arg_names(prokind,
+													   proargnames,
 													   proargmodes,
 													   &old_arg_names);
-			n_new_arg_names = get_func_input_arg_names(parameterNames,
+			n_new_arg_names = get_func_input_arg_names(prokind,
+													   parameterNames,
 													   parameterModes,
 													   &new_arg_names);
 			for (j = 0; j < n_old_arg_names; j++)
diff --git a/src/backend/commands/functioncmds.c b/src/backend/commands/functioncmds.c
index e236581a8e0..c3ce480c8f5 100644
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -194,8 +194,8 @@ interpret_function_parameter_list(ParseState *pstate,
 								  Oid *requiredResultType)
 {
 	int			parameterCount = list_length(parameters);
-	Oid		   *inTypes;
-	int			inCount = 0;
+	Oid		   *sigArgTypes;
+	int			sigArgCount = 0;
 	Datum	   *allTypes;
 	Datum	   *paramModes;
 	Datum	   *paramNames;
@@ -209,7 +209,7 @@ interpret_function_parameter_list(ParseState *pstate,
 	*variadicArgType = InvalidOid;	/* default result */
 	*requiredResultType = InvalidOid;	/* default result */
 
-	inTypes = (Oid *) palloc(parameterCount * sizeof(Oid));
+	sigArgTypes = (Oid *) palloc(parameterCount * sizeof(Oid));
 	allTypes = (Datum *) palloc(parameterCount * sizeof(Datum));
 	paramModes = (Datum *) palloc(parameterCount * sizeof(Datum));
 	paramNames = (Datum *) palloc0(parameterCount * sizeof(Datum));
@@ -281,25 +281,21 @@ interpret_function_parameter_list(ParseState *pstate,
 						 errmsg("functions cannot accept set arguments")));
 		}
 
-		if (objtype == OBJECT_PROCEDURE)
-		{
-			if (fp->mode == FUNC_PARAM_OUT)
-				ereport(ERROR,
-						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-						 errmsg("procedures cannot have OUT arguments"),
-						 errhint("INOUT arguments are permitted.")));
-		}
-
 		/* handle input parameters */
 		if (fp->mode != FUNC_PARAM_OUT && fp->mode != FUNC_PARAM_TABLE)
+			isinput = true;
+
+		/* handle signature parameters */
+		if (fp->mode == FUNC_PARAM_IN || fp->mode == FUNC_PARAM_INOUT ||
+			(objtype == OBJECT_PROCEDURE && fp->mode == FUNC_PARAM_OUT) ||
+			fp->mode == FUNC_PARAM_VARIADIC)
 		{
-			/* other input parameters can't follow a VARIADIC parameter */
+			/* other signature parameters can't follow a VARIADIC parameter */
 			if (varCount > 0)
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
-						 errmsg("VARIADIC parameter must be the last input parameter")));
-			inTypes[inCount++] = toid;
-			isinput = true;
+						 errmsg("VARIADIC parameter must be the last signature parameter")));
+			sigArgTypes[sigArgCount++] = toid;
 		}
 
 		/* handle output parameters */
@@ -429,7 +425,7 @@ interpret_function_parameter_list(ParseState *pstate,
 	}
 
 	/* Now construct the proper outputs as needed */
-	*parameterTypes = buildoidvector(inTypes, inCount);
+	*parameterTypes = buildoidvector(sigArgTypes, sigArgCount);
 
 	if (outCount > 0 || varCount > 0)
 	{
@@ -2067,6 +2063,9 @@ ExecuteCallStmt(CallStmt *stmt, ParamListInfo params, bool atomic, DestReceiver
 	int			nargs;
 	int			i;
 	AclResult	aclresult;
+	Oid		   *argtypes;
+	char	  **argnames;
+	char	   *argmodes;
 	FmgrInfo	flinfo;
 	CallContext *callcontext;
 	EState	   *estate;
@@ -2127,6 +2126,8 @@ ExecuteCallStmt(CallStmt *stmt, ParamListInfo params, bool atomic, DestReceiver
 											tp);
 	nargs = list_length(fexpr->args);
 
+	get_func_arg_info(tp, &argtypes, &argnames, &argmodes);
+
 	ReleaseSysCache(tp);
 
 	/* safety check; see ExecInitFunc() */
@@ -2156,16 +2157,24 @@ ExecuteCallStmt(CallStmt *stmt, ParamListInfo params, bool atomic, DestReceiver
 	i = 0;
 	foreach(lc, fexpr->args)
 	{
-		ExprState  *exprstate;
-		Datum		val;
-		bool		isnull;
+		if (argmodes && argmodes[i] == PROARGMODE_OUT)
+		{
+			fcinfo->args[i].value = 0;
+			fcinfo->args[i].isnull = true;
+		}
+		else
+		{
+			ExprState  *exprstate;
+			Datum		val;
+			bool		isnull;
 
-		exprstate = ExecPrepareExpr(lfirst(lc), estate);
+			exprstate = ExecPrepareExpr(lfirst(lc), estate);
 
-		val = ExecEvalExprSwitchContext(exprstate, econtext, &isnull);
+			val = ExecEvalExprSwitchContext(exprstate, econtext, &isnull);
 
-		fcinfo->args[i].value = val;
-		fcinfo->args[i].isnull = isnull;
+			fcinfo->args[i].value = val;
+			fcinfo->args[i].isnull = isnull;
+		}
 
 		i++;
 	}
diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c
index f940f48c6da..bf00a9c1e8d 100644
--- a/src/backend/executor/functions.c
+++ b/src/backend/executor/functions.c
@@ -259,7 +259,8 @@ prepare_sql_fn_parse_info(HeapTuple procedureTuple,
 		if (isNull)
 			proargmodes = PointerGetDatum(NULL);	/* just to be sure */
 
-		n_arg_names = get_func_input_arg_names(proargnames, proargmodes,
+		n_arg_names = get_func_input_arg_names(procedureStruct->prokind,
+											   proargnames, proargmodes,
 											   &pinfo->argnames);
 
 		/* Paranoia: ignore the result if too few array entries */
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 17653ef3a79..0d101d81715 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -166,7 +166,7 @@ static RoleSpec *makeRoleSpec(RoleSpecType type, int location);
 static void check_qualified_name(List *names, core_yyscan_t yyscanner);
 static List *check_func_name(List *names, core_yyscan_t yyscanner);
 static List *check_indirection(List *indirection, core_yyscan_t yyscanner);
-static List *extractArgTypes(List *parameters);
+static List *extractArgTypes(ObjectType objtype, List *parameters);
 static List *extractAggrArgTypes(List *aggrargs);
 static List *makeOrderedSetArgs(List *directargs, List *orderedargs,
 								core_yyscan_t yyscanner);
@@ -375,8 +375,8 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <accesspriv> privilege
 %type <list>	privileges privilege_list
 %type <privtarget> privilege_target
-%type <objwithargs> function_with_argtypes aggregate_with_argtypes operator_with_argtypes
-%type <list>	function_with_argtypes_list aggregate_with_argtypes_list operator_with_argtypes_list
+%type <objwithargs> function_with_argtypes aggregate_with_argtypes operator_with_argtypes procedure_with_argtypes function_with_argtypes_common
+%type <list>	function_with_argtypes_list aggregate_with_argtypes_list operator_with_argtypes_list procedure_with_argtypes_list
 %type <ival>	defacl_privilege_target
 %type <defelt>	DefACLOption
 %type <list>	DefACLOptionList
@@ -4623,7 +4623,7 @@ AlterExtensionContentsStmt:
 					n->object = (Node *) lcons(makeString($9), $7);
 					$$ = (Node *)n;
 				}
-			| ALTER EXTENSION name add_drop PROCEDURE function_with_argtypes
+			| ALTER EXTENSION name add_drop PROCEDURE procedure_with_argtypes
 				{
 					AlterExtensionContentsStmt *n = makeNode(AlterExtensionContentsStmt);
 					n->extname = $3;
@@ -4632,7 +4632,7 @@ AlterExtensionContentsStmt:
 					n->object = (Node *) $6;
 					$$ = (Node *)n;
 				}
-			| ALTER EXTENSION name add_drop ROUTINE function_with_argtypes
+			| ALTER EXTENSION name add_drop ROUTINE procedure_with_argtypes
 				{
 					AlterExtensionContentsStmt *n = makeNode(AlterExtensionContentsStmt);
 					n->extname = $3;
@@ -6365,7 +6365,7 @@ CommentStmt:
 					n->comment = $8;
 					$$ = (Node *) n;
 				}
-			| COMMENT ON PROCEDURE function_with_argtypes IS comment_text
+			| COMMENT ON PROCEDURE procedure_with_argtypes IS comment_text
 				{
 					CommentStmt *n = makeNode(CommentStmt);
 					n->objtype = OBJECT_PROCEDURE;
@@ -6373,7 +6373,7 @@ CommentStmt:
 					n->comment = $6;
 					$$ = (Node *) n;
 				}
-			| COMMENT ON ROUTINE function_with_argtypes IS comment_text
+			| COMMENT ON ROUTINE procedure_with_argtypes IS comment_text
 				{
 					CommentStmt *n = makeNode(CommentStmt);
 					n->objtype = OBJECT_ROUTINE;
@@ -6519,7 +6519,7 @@ SecLabelStmt:
 					n->label = $9;
 					$$ = (Node *) n;
 				}
-			| SECURITY LABEL opt_provider ON PROCEDURE function_with_argtypes
+			| SECURITY LABEL opt_provider ON PROCEDURE procedure_with_argtypes
 			  IS security_label
 				{
 					SecLabelStmt *n = makeNode(SecLabelStmt);
@@ -6880,7 +6880,7 @@ privilege_target:
 					n->objs = $2;
 					$$ = n;
 				}
-			| PROCEDURE function_with_argtypes_list
+			| PROCEDURE procedure_with_argtypes_list
 				{
 					PrivTarget *n = (PrivTarget *) palloc(sizeof(PrivTarget));
 					n->targtype = ACL_TARGET_OBJECT;
@@ -6888,7 +6888,7 @@ privilege_target:
 					n->objs = $2;
 					$$ = n;
 				}
-			| ROUTINE function_with_argtypes_list
+			| ROUTINE procedure_with_argtypes_list
 				{
 					PrivTarget *n = (PrivTarget *) palloc(sizeof(PrivTarget));
 					n->targtype = ACL_TARGET_OBJECT;
@@ -7409,20 +7409,33 @@ function_with_argtypes_list:
 													{ $$ = lappend($1, $3); }
 		;
 
+procedure_with_argtypes_list:
+			procedure_with_argtypes					{ $$ = list_make1($1); }
+			| procedure_with_argtypes_list ',' procedure_with_argtypes
+													{ $$ = lappend($1, $3); }
+		;
+
 function_with_argtypes:
 			func_name func_args
 				{
 					ObjectWithArgs *n = makeNode(ObjectWithArgs);
 					n->objname = $1;
-					n->objargs = extractArgTypes($2);
+					n->objargs = extractArgTypes(OBJECT_FUNCTION, $2);
 					$$ = n;
 				}
+			| function_with_argtypes_common
+				{
+					$$ = $1;
+				}
+		;
+
+function_with_argtypes_common:
 			/*
 			 * 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
+			type_func_name_keyword
 				{
 					ObjectWithArgs *n = makeNode(ObjectWithArgs);
 					n->objname = list_make1(makeString(pstrdup($1)));
@@ -7447,6 +7460,24 @@ function_with_argtypes:
 		;
 
 /*
+ * This is different from function_with_argtypes in the call to
+ * extractArgTypes().
+ */
+procedure_with_argtypes:
+			func_name func_args
+				{
+					ObjectWithArgs *n = makeNode(ObjectWithArgs);
+					n->objname = $1;
+					n->objargs = extractArgTypes(OBJECT_PROCEDURE, $2);
+					$$ = n;
+				}
+			| function_with_argtypes_common
+				{
+					$$ = $1;
+				}
+		;
+
+/*
  * func_args_with_defaults is separate because we only want to accept
  * defaults in CREATE FUNCTION, not in ALTER etc.
  */
@@ -7824,7 +7855,7 @@ AlterFunctionStmt:
 					n->actions = $4;
 					$$ = (Node *) n;
 				}
-			| ALTER PROCEDURE function_with_argtypes alterfunc_opt_list opt_restrict
+			| ALTER PROCEDURE procedure_with_argtypes alterfunc_opt_list opt_restrict
 				{
 					AlterFunctionStmt *n = makeNode(AlterFunctionStmt);
 					n->objtype = OBJECT_PROCEDURE;
@@ -7832,7 +7863,7 @@ AlterFunctionStmt:
 					n->actions = $4;
 					$$ = (Node *) n;
 				}
-			| ALTER ROUTINE function_with_argtypes alterfunc_opt_list opt_restrict
+			| ALTER ROUTINE procedure_with_argtypes alterfunc_opt_list opt_restrict
 				{
 					AlterFunctionStmt *n = makeNode(AlterFunctionStmt);
 					n->objtype = OBJECT_ROUTINE;
@@ -7888,7 +7919,7 @@ RemoveFuncStmt:
 					n->concurrent = false;
 					$$ = (Node *)n;
 				}
-			| DROP PROCEDURE function_with_argtypes_list opt_drop_behavior
+			| DROP PROCEDURE procedure_with_argtypes_list opt_drop_behavior
 				{
 					DropStmt *n = makeNode(DropStmt);
 					n->removeType = OBJECT_PROCEDURE;
@@ -7898,7 +7929,7 @@ RemoveFuncStmt:
 					n->concurrent = false;
 					$$ = (Node *)n;
 				}
-			| DROP PROCEDURE IF_P EXISTS function_with_argtypes_list opt_drop_behavior
+			| DROP PROCEDURE IF_P EXISTS procedure_with_argtypes_list opt_drop_behavior
 				{
 					DropStmt *n = makeNode(DropStmt);
 					n->removeType = OBJECT_PROCEDURE;
@@ -7908,7 +7939,7 @@ RemoveFuncStmt:
 					n->concurrent = false;
 					$$ = (Node *)n;
 				}
-			| DROP ROUTINE function_with_argtypes_list opt_drop_behavior
+			| DROP ROUTINE procedure_with_argtypes_list opt_drop_behavior
 				{
 					DropStmt *n = makeNode(DropStmt);
 					n->removeType = OBJECT_ROUTINE;
@@ -7918,7 +7949,7 @@ RemoveFuncStmt:
 					n->concurrent = false;
 					$$ = (Node *)n;
 				}
-			| DROP ROUTINE IF_P EXISTS function_with_argtypes_list opt_drop_behavior
+			| DROP ROUTINE IF_P EXISTS procedure_with_argtypes_list opt_drop_behavior
 				{
 					DropStmt *n = makeNode(DropStmt);
 					n->removeType = OBJECT_ROUTINE;
@@ -8393,7 +8424,7 @@ RenameStmt: ALTER AGGREGATE aggregate_with_argtypes RENAME TO name
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
-			| ALTER PROCEDURE function_with_argtypes RENAME TO name
+			| ALTER PROCEDURE procedure_with_argtypes RENAME TO name
 				{
 					RenameStmt *n = makeNode(RenameStmt);
 					n->renameType = OBJECT_PROCEDURE;
@@ -8411,7 +8442,7 @@ RenameStmt: ALTER AGGREGATE aggregate_with_argtypes RENAME TO name
 					n->missing_ok = false;
 					$$ = (Node *)n;
 				}
-			| ALTER ROUTINE function_with_argtypes RENAME TO name
+			| ALTER ROUTINE procedure_with_argtypes RENAME TO name
 				{
 					RenameStmt *n = makeNode(RenameStmt);
 					n->renameType = OBJECT_ROUTINE;
@@ -8822,7 +8853,7 @@ AlterObjectDependsStmt:
 					n->remove = $4;
 					$$ = (Node *)n;
 				}
-			| ALTER PROCEDURE function_with_argtypes opt_no DEPENDS ON EXTENSION name
+			| ALTER PROCEDURE procedure_with_argtypes opt_no DEPENDS ON EXTENSION name
 				{
 					AlterObjectDependsStmt *n = makeNode(AlterObjectDependsStmt);
 					n->objectType = OBJECT_PROCEDURE;
@@ -8831,7 +8862,7 @@ AlterObjectDependsStmt:
 					n->remove = $4;
 					$$ = (Node *)n;
 				}
-			| ALTER ROUTINE function_with_argtypes opt_no DEPENDS ON EXTENSION name
+			| ALTER ROUTINE procedure_with_argtypes opt_no DEPENDS ON EXTENSION name
 				{
 					AlterObjectDependsStmt *n = makeNode(AlterObjectDependsStmt);
 					n->objectType = OBJECT_ROUTINE;
@@ -8962,7 +8993,7 @@ AlterObjectSchemaStmt:
 					n->missing_ok = false;
 					$$ = (Node *)n;
 				}
-			| ALTER PROCEDURE function_with_argtypes SET SCHEMA name
+			| ALTER PROCEDURE procedure_with_argtypes SET SCHEMA name
 				{
 					AlterObjectSchemaStmt *n = makeNode(AlterObjectSchemaStmt);
 					n->objectType = OBJECT_PROCEDURE;
@@ -8971,7 +9002,7 @@ AlterObjectSchemaStmt:
 					n->missing_ok = false;
 					$$ = (Node *)n;
 				}
-			| ALTER ROUTINE function_with_argtypes SET SCHEMA name
+			| ALTER ROUTINE procedure_with_argtypes SET SCHEMA name
 				{
 					AlterObjectSchemaStmt *n = makeNode(AlterObjectSchemaStmt);
 					n->objectType = OBJECT_ROUTINE;
@@ -9273,7 +9304,7 @@ AlterOwnerStmt: ALTER AGGREGATE aggregate_with_argtypes OWNER TO RoleSpec
 					n->newowner = $9;
 					$$ = (Node *)n;
 				}
-			| ALTER PROCEDURE function_with_argtypes OWNER TO RoleSpec
+			| ALTER PROCEDURE procedure_with_argtypes OWNER TO RoleSpec
 				{
 					AlterOwnerStmt *n = makeNode(AlterOwnerStmt);
 					n->objectType = OBJECT_PROCEDURE;
@@ -9281,7 +9312,7 @@ AlterOwnerStmt: ALTER AGGREGATE aggregate_with_argtypes OWNER TO RoleSpec
 					n->newowner = $6;
 					$$ = (Node *)n;
 				}
-			| ALTER ROUTINE function_with_argtypes OWNER TO RoleSpec
+			| ALTER ROUTINE procedure_with_argtypes OWNER TO RoleSpec
 				{
 					AlterOwnerStmt *n = makeNode(AlterOwnerStmt);
 					n->objectType = OBJECT_ROUTINE;
@@ -16218,13 +16249,14 @@ check_indirection(List *indirection, core_yyscan_t yyscanner)
 }
 
 /* extractArgTypes()
+ *
  * Given a list of FunctionParameter nodes, extract a list of just the
- * argument types (TypeNames) for input parameters only.  This is what
- * is needed to look up an existing function, which is what is wanted by
- * the productions that use this call.
+ * argument types (TypeNames) for signature parameters only (e.g., only input
+ * parameters for functions).  This is what is needed to look up an existing
+ * function, which is what is wanted by the productions that use this call.
  */
 static List *
-extractArgTypes(List *parameters)
+extractArgTypes(ObjectType objtype, List *parameters)
 {
 	List	   *result = NIL;
 	ListCell   *i;
@@ -16233,7 +16265,7 @@ extractArgTypes(List *parameters)
 	{
 		FunctionParameter *p = (FunctionParameter *) lfirst(i);
 
-		if (p->mode != FUNC_PARAM_OUT && p->mode != FUNC_PARAM_TABLE)
+		if ((p->mode != FUNC_PARAM_OUT || objtype == OBJECT_PROCEDURE) && p->mode != FUNC_PARAM_TABLE)
 			result = lappend(result, p->argType);
 	}
 	return result;
@@ -16246,7 +16278,7 @@ static List *
 extractAggrArgTypes(List *aggrargs)
 {
 	Assert(list_length(aggrargs) == 2);
-	return extractArgTypes((List *) linitial(aggrargs));
+	return extractArgTypes(OBJECT_AGGREGATE, (List *) linitial(aggrargs));
 }
 
 /* makeOrderedSetArgs()
diff --git a/src/backend/utils/fmgr/funcapi.c b/src/backend/utils/fmgr/funcapi.c
index 78ed8572038..b9efa772915 100644
--- a/src/backend/utils/fmgr/funcapi.c
+++ b/src/backend/utils/fmgr/funcapi.c
@@ -1233,7 +1233,8 @@ get_func_trftypes(HeapTuple procTup,
  * are set to NULL.  You don't get anything if proargnames is NULL.
  */
 int
-get_func_input_arg_names(Datum proargnames, Datum proargmodes,
+get_func_input_arg_names(char prokind,
+						 Datum proargnames, Datum proargmodes,
 						 char ***arg_names)
 {
 	ArrayType  *arr;
@@ -1291,6 +1292,7 @@ get_func_input_arg_names(Datum proargnames, Datum proargmodes,
 		if (argmodes == NULL ||
 			argmodes[i] == PROARGMODE_IN ||
 			argmodes[i] == PROARGMODE_INOUT ||
+			(argmodes[i] == PROARGMODE_OUT && prokind == PROKIND_PROCEDURE) ||
 			argmodes[i] == PROARGMODE_VARIADIC)
 		{
 			char	   *pname = TextDatumGetCString(argnames[i]);