check_sql_fn_retval has always thought that we supported doing

'SELECT foo()' in a SQL function returning a rowtype, to simply pass
back the results of another function returning the same rowtype.
However, that hasn't actually worked in many years.  Now it works again.

src/backend/catalog/pg_proc.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/pg_proc.c,v 1.114 2004/04/01 21:28:44 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/pg_proc.c,v 1.115 2004/04/02 23:14:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -362,8 +362,13 @@ create_parameternames_array(int parameterCount, const char *parameterNames[])
  * function execution startup.	The rettype is then the actual resolved
  * output type of the function, rather than the declared type.	(Therefore,
  * we should never see ANYARRAY or ANYELEMENT as rettype.)
+ *
+ * The return value is true if the function returns the entire tuple result
+ * of its final SELECT, and false otherwise.  Note that because we allow
+ * "SELECT rowtype_expression", this may be false even when the declared
+ * function return type is a rowtype.
  */
-void
+bool
 check_sql_fn_retval(Oid rettype, char fn_typtype, List *queryTreeList)
 {
 	Query	   *parse;
@@ -387,7 +392,7 @@ check_sql_fn_retval(Oid rettype, char fn_typtype, List *queryTreeList)
 					 errmsg("return type mismatch in function declared to return %s",
 							format_type_be(rettype)),
 			 errdetail("Function's final statement must be a SELECT.")));
-		return;
+		return false;
 	}
 
 	/* find the final query */
@@ -408,7 +413,7 @@ check_sql_fn_retval(Oid rettype, char fn_typtype, List *queryTreeList)
 					 errmsg("return type mismatch in function declared to return %s",
 							format_type_be(rettype)),
 					 errdetail("Function's final statement must not be a SELECT.")));
-		return;
+		return false;
 	}
 
 	/* by here, the function is declared to return some type */
@@ -468,7 +473,7 @@ check_sql_fn_retval(Oid rettype, char fn_typtype, List *queryTreeList)
 		{
 			restype = ((TargetEntry *) lfirst(tlist))->resdom->restype;
 			if (IsBinaryCoercible(restype, rettype))
-				return;
+				return false;	/* NOT returning whole tuple */
 		}
 
 		/*
@@ -536,16 +541,31 @@ check_sql_fn_retval(Oid rettype, char fn_typtype, List *queryTreeList)
 					 errdetail("Final SELECT returns too few columns.")));
 
 		relation_close(reln, AccessShareLock);
+
+		/* Report that we are returning entire tuple result */
+		return true;
 	}
 	else if (rettype == RECORDOID)
 	{
-		/* Shouldn't have a typerelid */
-		Assert(typerelid == InvalidOid);
+		/*
+		 * If the target list is of length 1, and the type of the varnode
+		 * in the target list matches the declared return type, this is
+		 * okay. This can happen, for example, where the body of the
+		 * function is 'SELECT func2()', where func2 has the same return
+		 * type as the function that's calling it.
+		 */
+		if (tlistlen == 1)
+		{
+			restype = ((TargetEntry *) lfirst(tlist))->resdom->restype;
+			if (IsBinaryCoercible(restype, rettype))
+				return false;	/* NOT returning whole tuple */
+		}
 
 		/*
-		 * For RECORD return type, defer this check until we get the first
-		 * tuple.
+		 * Otherwise assume we are returning the whole tuple.  Crosschecking
+		 * against what the caller expects will happen at runtime.
 		 */
+		return true;
 	}
 	else if (rettype == ANYARRAYOID || rettype == ANYELEMENTOID)
 	{
@@ -560,6 +580,8 @@ check_sql_fn_retval(Oid rettype, char fn_typtype, List *queryTreeList)
 				(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 			  errmsg("return type %s is not supported for SQL functions",
 					 format_type_be(rettype))));
+
+	return false;
 }
 
 
@@ -751,7 +773,8 @@ fmgr_sql_validator(PG_FUNCTION_ARGS)
 			querytree_list = pg_parse_and_rewrite(prosrc,
 												  proc->proargtypes,
 												  proc->pronargs);
-			check_sql_fn_retval(proc->prorettype, functyptype, querytree_list);
+			(void) check_sql_fn_retval(proc->prorettype, functyptype,
+									   querytree_list);
 		}
 		else
 			querytree_list = pg_parse_query(prosrc);

src/backend/executor/functions.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/functions.c,v 1.79 2004/04/01 21:28:44 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/functions.c,v 1.80 2004/04/02 23:14:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -73,9 +73,7 @@ typedef SQLFunctionCache *SQLFunctionCachePtr;
 
 
 /* non-export function prototypes */
-static execution_state *init_execution_state(char *src,
-					 Oid *argOidVect, int nargs,
-					 Oid rettype, bool haspolyarg);
+static execution_state *init_execution_state(List *queryTree_list);
 static void init_sql_fcache(FmgrInfo *finfo);
 static void postquel_start(execution_state *es, SQLFunctionCachePtr fcache);
 static TupleTableSlot *postquel_getnext(execution_state *es);
@@ -90,25 +88,11 @@ static void ShutdownSQLFunction(Datum arg);
 
 
 static execution_state *
-init_execution_state(char *src, Oid *argOidVect, int nargs,
-					 Oid rettype, bool haspolyarg)
+init_execution_state(List *queryTree_list)
 {
-	execution_state *firstes;
-	execution_state *preves;
-	List	   *queryTree_list,
-			   *qtl_item;
-
-	queryTree_list = pg_parse_and_rewrite(src, argOidVect, nargs);
-
-	/*
-	 * If the function has any arguments declared as polymorphic types,
-	 * then it wasn't type-checked at definition time; must do so now.
-	 */
-	if (haspolyarg)
-		check_sql_fn_retval(rettype, get_typtype(rettype), queryTree_list);
-
-	firstes = NULL;
-	preves = NULL;
+	execution_state *firstes = NULL;
+	execution_state *preves = NULL;
+	List	   *qtl_item;
 
 	foreach(qtl_item, queryTree_list)
 	{
@@ -151,6 +135,7 @@ init_sql_fcache(FmgrInfo *finfo)
 	bool		haspolyarg;
 	char	   *src;
 	int			nargs;
+	List	   *queryTree_list;
 	Datum		tmp;
 	bool		isNull;
 
@@ -191,7 +176,9 @@ init_sql_fcache(FmgrInfo *finfo)
 	typeStruct = (Form_pg_type) GETSTRUCT(typeTuple);
 
 	/*
-	 * get the type length and by-value flag from the type tuple
+	 * get the type length and by-value flag from the type tuple; also
+	 * do a preliminary check for returnsTuple (this may prove inaccurate,
+	 * see below).
 	 */
 	fcache->typlen = typeStruct->typlen;
 	fcache->typbyval = typeStruct->typbyval;
@@ -199,7 +186,7 @@ init_sql_fcache(FmgrInfo *finfo)
 							rettype == RECORDOID);
 
 	/*
-	 * Parse and plan the queries.	We need the argument type info to pass
+	 * Parse and rewrite the queries.  We need the argument type info to pass
 	 * to the parser.
 	 */
 	nargs = procedureStruct->pronargs;
@@ -242,8 +229,25 @@ init_sql_fcache(FmgrInfo *finfo)
 		elog(ERROR, "null prosrc for function %u", foid);
 	src = DatumGetCString(DirectFunctionCall1(textout, tmp));
 
-	fcache->func_state = init_execution_state(src, argOidVect, nargs,
-											  rettype, haspolyarg);
+	queryTree_list = pg_parse_and_rewrite(src, argOidVect, nargs);
+
+	/*
+	 * If the function has any arguments declared as polymorphic types,
+	 * then it wasn't type-checked at definition time; must do so now.
+	 *
+	 * Also, force a type-check if the declared return type is a rowtype;
+	 * we need to find out whether we are actually returning the whole
+	 * tuple result, or just regurgitating a rowtype expression result.
+	 * In the latter case we clear returnsTuple because we need not act
+	 * different from the scalar result case.
+	 */
+	if (haspolyarg || fcache->returnsTuple)
+		fcache->returnsTuple = check_sql_fn_retval(rettype,
+												   get_typtype(rettype),
+												   queryTree_list);
+
+	/* Finally, plan the queries */
+	fcache->func_state = init_execution_state(queryTree_list);
 
 	pfree(src);
 

src/backend/optimizer/util/clauses.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.168 2004/04/02 19:06:57 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.169 2004/04/02 23:14:08 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -1992,8 +1992,8 @@ inline_function(Oid funcid, Oid result_type, List *args,
 	 * probably not important, but let's be careful.)
 	 */
 	if (polymorphic)
-		check_sql_fn_retval(result_type, get_typtype(result_type),
-							querytree_list);
+		(void) check_sql_fn_retval(result_type, get_typtype(result_type),
+								   querytree_list);
 
 	/*
 	 * Additional validity checks on the expression.  It mustn't return a

src/include/catalog/pg_proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.323 2004/04/01 21:28:45 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.324 2004/04/02 23:14:08 tgl Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -3560,7 +3560,7 @@ extern Oid ProcedureCreate(const char *procedureName,
 				const Oid *parameterTypes,
 				const char *parameterNames[]);
 
-extern void check_sql_fn_retval(Oid rettype, char fn_typtype,
+extern bool check_sql_fn_retval(Oid rettype, char fn_typtype,
 					List *queryTreeList);
 
 extern bool function_parse_error_transpose(const char *prosrc);