Allow functions returning void or cstring to appear in FROM clause,

to make life cushy for the JDBC driver.  Centralize the decision-making
that affects this by inventing a get_type_func_class() function, rather
than adding special cases in half a dozen places.

src/backend/access/common/tupdesc.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/common/tupdesc.c,v 1.106 2004/08/29 05:06:39 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/common/tupdesc.c,v 1.107 2004/10/20 16:04:47 tgl Exp $
  *
  * NOTES
  *	  some of the executor utility code such as "ExecTypeFromTL" should be
@@ -607,13 +607,13 @@ RelationNameGetTupleDesc(const char *relname)
 TupleDesc
 TypeGetTupleDesc(Oid typeoid, List *colaliases)
 {
-	char		functyptype = get_typtype(typeoid);
+	TypeFuncClass functypclass = get_type_func_class(typeoid);
 	TupleDesc	tupdesc = NULL;
 
 	/*
 	 * Build a suitable tupledesc representing the output rows
 	 */
-	if (functyptype == 'c')
+	if (functypclass == TYPEFUNC_COMPOSITE)
 	{
 		/* Composite data type, e.g. a table's row type */
 		tupdesc = CreateTupleDescCopy(lookup_rowtype_tupdesc(typeoid, -1));
@@ -643,9 +643,9 @@ TypeGetTupleDesc(Oid typeoid, List *colaliases)
 			tupdesc->tdtypmod = -1;
 		}
 	}
-	else if (functyptype == 'b' || functyptype == 'd')
+	else if (functypclass == TYPEFUNC_SCALAR)
 	{
-		/* Must be a base data type, i.e. scalar */
+		/* Base data type, i.e. scalar */
 		char	   *attname;
 
 		/* the alias list is required for base types */
@@ -671,7 +671,7 @@ TypeGetTupleDesc(Oid typeoid, List *colaliases)
 						   -1,
 						   0);
 	}
-	else if (typeoid == RECORDOID)
+	else if (functypclass == TYPEFUNC_RECORD)
 	{
 		/* XXX can't support this because typmod wasn't passed in ... */
 		ereport(ERROR,

src/backend/executor/nodeFunctionscan.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeFunctionscan.c,v 1.27 2004/09/22 17:41:51 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeFunctionscan.c,v 1.28 2004/10/20 16:04:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -132,7 +132,7 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate)
 	FunctionScanState *scanstate;
 	RangeTblEntry *rte;
 	Oid			funcrettype;
-	char		functyptype;
+	TypeFuncClass functypclass;
 	TupleDesc	tupdesc = NULL;
 
 	/*
@@ -184,16 +184,16 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate)
 	 * Now determine if the function returns a simple or composite type,
 	 * and build an appropriate tupdesc.
 	 */
-	functyptype = get_typtype(funcrettype);
+	functypclass = get_type_func_class(funcrettype);
 
-	if (functyptype == 'c')
+	if (functypclass == TYPEFUNC_COMPOSITE)
 	{
 		/* Composite data type, e.g. a table's row type */
 		tupdesc = CreateTupleDescCopy(lookup_rowtype_tupdesc(funcrettype, -1));
 	}
-	else if (functyptype == 'b' || functyptype == 'd')
+	else if (functypclass == TYPEFUNC_SCALAR)
 	{
-		/* Must be a base data type, i.e. scalar */
+		/* Base data type, i.e. scalar */
 		char	   *attname = strVal(linitial(rte->eref->colnames));
 
 		tupdesc = CreateTemplateTupleDesc(1, false);
@@ -204,9 +204,8 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate)
 						   -1,
 						   0);
 	}
-	else if (funcrettype == RECORDOID)
+	else if (functypclass == TYPEFUNC_RECORD)
 	{
-		/* Must be a pseudo type, i.e. record */
 		tupdesc = BuildDescForRelation(rte->coldeflist);
 	}
 	else

src/backend/parser/parse_relation.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.100 2004/08/29 05:06:44 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.101 2004/10/20 16:04:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -966,7 +966,7 @@ addRangeTableEntryForFunction(ParseState *pstate,
 {
 	RangeTblEntry *rte = makeNode(RangeTblEntry);
 	Oid			funcrettype = exprType(funcexpr);
-	char		functyptype;
+	TypeFuncClass functypclass;
 	Alias	   *alias = rangefunc->alias;
 	List	   *coldeflist = rangefunc->coldeflist;
 	Alias	   *eref;
@@ -1008,18 +1008,15 @@ addRangeTableEntryForFunction(ParseState *pstate,
 					 errmsg("a column definition list is required for functions returning \"record\"")));
 	}
 
-	functyptype = get_typtype(funcrettype);
+	functypclass = get_type_func_class(funcrettype);
 
-	if (functyptype == 'c')
+	if (functypclass == TYPEFUNC_COMPOSITE)
 	{
-		/*
-		 * Named composite data type, i.e. a table's row type
-		 */
+		/* Composite data type, e.g. a table's row type */
 		Oid			funcrelid = typeidTypeRelid(funcrettype);
 		Relation	rel;
 
-		if (!OidIsValid(funcrelid))		/* shouldn't happen if typtype is
-										 * 'c' */
+		if (!OidIsValid(funcrelid))		/* shouldn't happen */
 			elog(ERROR, "invalid typrelid for complex type %u", funcrettype);
 
 		/*
@@ -1038,12 +1035,10 @@ addRangeTableEntryForFunction(ParseState *pstate,
 		 */
 		relation_close(rel, NoLock);
 	}
-	else if (functyptype == 'b' || functyptype == 'd')
+	else if (functypclass == TYPEFUNC_SCALAR)
 	{
-		/*
-		 * Must be a base data type, i.e. scalar. Just add one alias
-		 * column named for the function.
-		 */
+		/* Base data type, i.e. scalar */
+		/* Just add one alias column named for the function. */
 		if (alias && alias->colnames != NIL)
 		{
 			if (list_length(alias->colnames) != 1)
@@ -1056,7 +1051,7 @@ addRangeTableEntryForFunction(ParseState *pstate,
 		else
 			eref->colnames = list_make1(makeString(eref->aliasname));
 	}
-	else if (functyptype == 'p' && funcrettype == RECORDOID)
+	else if (functypclass == TYPEFUNC_RECORD)
 	{
 		ListCell   *col;
 
@@ -1073,8 +1068,8 @@ addRangeTableEntryForFunction(ParseState *pstate,
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_DATATYPE_MISMATCH),
-			errmsg("function \"%s\" in FROM has unsupported return type",
-				   funcname)));
+			errmsg("function \"%s\" in FROM has unsupported return type %s",
+				   funcname, format_type_be(funcrettype))));
 
 	/*----------
 	 * Flags:
@@ -1314,9 +1309,9 @@ expandRTE(List *rtable, int rtindex, int sublevels_up,
 			{
 				/* Function RTE */
 				Oid			funcrettype = exprType(rte->funcexpr);
-				char		functyptype = get_typtype(funcrettype);
+				TypeFuncClass functypclass = get_type_func_class(funcrettype);
 
-				if (functyptype == 'c')
+				if (functypclass == TYPEFUNC_COMPOSITE)
 				{
 					/*
 					 * Composite data type, i.e. a table's row type
@@ -1332,11 +1327,9 @@ expandRTE(List *rtable, int rtindex, int sublevels_up,
 					expandRelation(funcrelid, rte->eref, rtindex, sublevels_up,
 								   include_dropped, colnames, colvars);
 				}
-				else if (functyptype == 'b' || functyptype == 'd')
+				else if (functypclass == TYPEFUNC_SCALAR)
 				{
-					/*
-					 * Must be a base data type, i.e. scalar
-					 */
+					/* Base data type, i.e. scalar */
 					if (colnames)
 						*colnames = lappend(*colnames,
 										  linitial(rte->eref->colnames));
@@ -1352,7 +1345,7 @@ expandRTE(List *rtable, int rtindex, int sublevels_up,
 						*colvars = lappend(*colvars, varnode);
 					}
 				}
-				else if (functyptype == 'p' && funcrettype == RECORDOID)
+				else if (functypclass == TYPEFUNC_RECORD)
 				{
 					List	   *coldeflist = rte->coldeflist;
 					ListCell   *col;
@@ -1389,9 +1382,10 @@ expandRTE(List *rtable, int rtindex, int sublevels_up,
 					}
 				}
 				else
-					ereport(ERROR,
-							(errcode(ERRCODE_DATATYPE_MISMATCH),
-							 errmsg("function in FROM has unsupported return type")));
+				{
+					/* addRangeTableEntryForFunction should've caught this */
+					elog(ERROR, "function in FROM has unsupported return type");
+				}
 			}
 			break;
 		case RTE_JOIN:
@@ -1669,14 +1663,15 @@ get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
 			{
 				/* Function RTE */
 				Oid			funcrettype = exprType(rte->funcexpr);
-				char		functyptype = get_typtype(funcrettype);
+				TypeFuncClass functypclass = get_type_func_class(funcrettype);
 				List	   *coldeflist = rte->coldeflist;
 
-				if (functyptype == 'c')
+				if (functypclass == TYPEFUNC_COMPOSITE)
 				{
 					/*
-					 * Composite data type, i.e. a table's row type Same
-					 * as ordinary relation RTE
+					 * Composite data type, i.e. a table's row type
+					 *
+					 * Same as ordinary relation RTE
 					 */
 					Oid			funcrelid = typeidTypeRelid(funcrettype);
 					HeapTuple	tp;
@@ -1709,15 +1704,13 @@ get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
 					*vartypmod = att_tup->atttypmod;
 					ReleaseSysCache(tp);
 				}
-				else if (functyptype == 'b' || functyptype == 'd')
+				else if (functypclass == TYPEFUNC_SCALAR)
 				{
-					/*
-					 * Must be a base data type, i.e. scalar
-					 */
+					/* Base data type, i.e. scalar */
 					*vartype = funcrettype;
 					*vartypmod = -1;
 				}
-				else if (functyptype == 'p' && funcrettype == RECORDOID)
+				else if (functypclass == TYPEFUNC_RECORD)
 				{
 					ColumnDef  *colDef = list_nth(coldeflist, attnum - 1);
 
@@ -1725,9 +1718,10 @@ get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
 					*vartypmod = -1;
 				}
 				else
-					ereport(ERROR,
-							(errcode(ERRCODE_DATATYPE_MISMATCH),
-							 errmsg("function in FROM has unsupported return type")));
+				{
+					/* addRangeTableEntryForFunction should've caught this */
+					elog(ERROR, "function in FROM has unsupported return type");
+				}
 			}
 			break;
 		case RTE_JOIN:

src/backend/utils/cache/lsyscache.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.116 2004/08/29 05:06:50 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.117 2004/10/20 16:04:49 tgl Exp $
  *
  * NOTES
  *	  Eventually, the index information should go through here, too.
@@ -1547,6 +1547,42 @@ get_typtype(Oid typid)
 		return '\0';
 }
 
+/*
+ * get_type_func_class
+ *
+ *		Given the type OID, obtain its TYPEFUNC classification.
+ *
+ * This is intended to centralize a bunch of formerly ad-hoc code for
+ * classifying types.  The categories used here are useful for deciding
+ * how to handle functions returning the datatype.
+ */
+TypeFuncClass
+get_type_func_class(Oid typid)
+{
+	switch (get_typtype(typid))
+	{
+		case 'c':
+			return TYPEFUNC_COMPOSITE;
+		case 'b':
+		case 'd':
+			return TYPEFUNC_SCALAR;
+		case 'p':
+			if (typid == RECORDOID)
+				return TYPEFUNC_RECORD;
+			/*
+			 * We treat VOID and CSTRING as legitimate scalar datatypes,
+			 * mostly for the convenience of the JDBC driver (which wants
+			 * to be able to do "SELECT * FROM foo()" for all legitimately
+			 * user-callable functions).
+			 */
+			if (typid == VOIDOID || typid == CSTRINGOID)
+				return TYPEFUNC_SCALAR;
+			return TYPEFUNC_OTHER;
+	}
+	/* shouldn't get here, probably */
+	return TYPEFUNC_OTHER;
+}
+
 /*
  * get_typ_typrelid
  *

src/include/utils/lsyscache.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.90 2004/08/29 05:06:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.91 2004/10/20 16:04:50 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -24,6 +24,15 @@ typedef enum IOFuncSelector
 	IOFunc_send
 } IOFuncSelector;
 
+/* Type categories for get_type_func_class */
+typedef enum TypeFuncClass
+{
+	TYPEFUNC_SCALAR,
+	TYPEFUNC_COMPOSITE,
+	TYPEFUNC_RECORD,
+	TYPEFUNC_OTHER
+} TypeFuncClass;
+
 extern bool op_in_opclass(Oid opno, Oid opclass);
 extern void get_op_opclass_properties(Oid opno, Oid opclass,
 						  int *strategy, Oid *subtype,
@@ -85,6 +94,7 @@ extern char get_typstorage(Oid typid);
 extern int32 get_typtypmod(Oid typid);
 extern Node *get_typdefault(Oid typid);
 extern char get_typtype(Oid typid);
+extern TypeFuncClass get_type_func_class(Oid typid);
 extern Oid	get_typ_typrelid(Oid typid);
 extern Oid	get_element_type(Oid typid);
 extern Oid	get_array_type(Oid typid);