Add expected tuple descriptor to ReturnSetInfo information for table

functions, per suggestion from John Gray and Joe Conway.  Also, fix
plpgsql RETURN NEXT to verify that returned values match the expected
tupdesc.

Author: tglsfdc

src/backend/executor/execQual.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.102 2002/08/30 00:28:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.103 2002/08/30 23:59:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -707,6 +707,7 @@ ExecMakeFunctionResult(FunctionCachePtr fcache,
 		fcinfo.resultinfo = (Node *) &rsinfo;
 		rsinfo.type = T_ReturnSetInfo;
 		rsinfo.econtext = econtext;
+		rsinfo.expectedDesc = NULL;
 		rsinfo.allowedModes = (int) SFRM_ValuePerCall;
 		rsinfo.returnMode = SFRM_ValuePerCall;
 		/* isDone is filled below */
@@ -851,6 +852,7 @@ ExecMakeFunctionResult(FunctionCachePtr fcache,
 Tuplestorestate *
 ExecMakeTableFunctionResult(Expr *funcexpr,
 							ExprContext *econtext,
+							TupleDesc expectedDesc,
 							TupleDesc *returnDesc)
 {
 	Tuplestorestate *tupstore = NULL;
@@ -859,7 +861,7 @@ ExecMakeTableFunctionResult(Expr *funcexpr,
 	List	   *argList;
 	FunctionCachePtr fcache;
 	FunctionCallInfoData fcinfo;
-	ReturnSetInfo rsinfo;		/* for functions returning sets */
+	ReturnSetInfo rsinfo;
 	ExprDoneCond argDone;
 	MemoryContext callerContext;
 	MemoryContext oldcontext;
@@ -918,17 +920,14 @@ ExecMakeTableFunctionResult(Expr *funcexpr,
 	}
 
 	/*
-	 * If function returns set, prepare a resultinfo node for
-	 * communication
+	 * Prepare a resultinfo node for communication.  We always do this even
+	 * if not expecting a set result, so that we can pass expectedDesc.
 	 */
-	if (fcache->func.fn_retset)
-	{
-		fcinfo.resultinfo = (Node *) &rsinfo;
-		rsinfo.type = T_ReturnSetInfo;
-		rsinfo.econtext = econtext;
-		rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize);
-	}
-	/* we set these fields always since we examine them below */
+	fcinfo.resultinfo = (Node *) &rsinfo;
+	rsinfo.type = T_ReturnSetInfo;
+	rsinfo.econtext = econtext;
+	rsinfo.expectedDesc = expectedDesc;
+	rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize);
 	rsinfo.returnMode = SFRM_ValuePerCall;
 	/* isDone is filled below */
 	rsinfo.setResult = NULL;

src/backend/executor/nodeFunctionscan.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeFunctionscan.c,v 1.8 2002/08/30 00:28:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeFunctionscan.c,v 1.9 2002/08/30 23:59:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -79,6 +79,7 @@ FunctionNext(FunctionScan *node)
 		scanstate->tuplestorestate = tuplestorestate =
 			ExecMakeTableFunctionResult((Expr *) scanstate->funcexpr,
 										econtext,
+										scanstate->tupdesc,
 										&funcTupdesc);
 
 		/*

src/backend/utils/fmgr/README

@@ -423,6 +423,11 @@ function is called in).  The function stores pointers to the Tuplestore and
 TupleDesc into ReturnSetInfo, sets returnMode to indicate materialize mode,
 and returns null.  isDone is not used and should be left at ExprSingleResult.
 
+If the function is being called as a table function (ie, it appears in a
+FROM item), then the expected tuple descriptor is passed in ReturnSetInfo;
+in other contexts the expectedDesc field will be NULL.  The function need
+not pay attention to expectedDesc, but it may be useful in special cases.
+
 There is no support for functions accepting sets; instead, the function will
 be called multiple times, once for each element of the input set.
 

src/include/executor/executor.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: executor.h,v 1.75 2002/08/30 00:28:41 tgl Exp $
+ * $Id: executor.h,v 1.76 2002/08/30 23:59:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -82,6 +82,7 @@ extern Datum ExecMakeFunctionResult(FunctionCachePtr fcache,
 					   ExprDoneCond *isDone);
 extern Tuplestorestate *ExecMakeTableFunctionResult(Expr *funcexpr,
 													ExprContext *econtext,
+													TupleDesc expectedDesc,
 													TupleDesc *returnDesc);
 extern Datum ExecEvalExpr(Node *expression, ExprContext *econtext,
 			 bool *isNull, ExprDoneCond *isDone);

src/include/nodes/execnodes.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: execnodes.h,v 1.73 2002/08/30 00:28:41 tgl Exp $
+ * $Id: execnodes.h,v 1.74 2002/08/30 23:59:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -147,12 +147,16 @@ typedef enum
 typedef struct ReturnSetInfo
 {
 	NodeTag		type;
+	/* values set by caller: */
 	ExprContext *econtext;		/* context function is being called in */
+	TupleDesc	expectedDesc;	/* tuple descriptor expected by caller */
 	int			allowedModes;	/* bitmask: return modes caller can handle */
-	SetFunctionReturnMode	returnMode;	/* actual return mode */
+	/* result status from function (but pre-initialized by caller): */
+	SetFunctionReturnMode returnMode;	/* actual return mode */
 	ExprDoneCond isDone;		/* status for ValuePerCall mode */
-	Tuplestorestate *setResult;	/* return object for Materialize mode */
-	TupleDesc	setDesc;		/* descriptor for Materialize mode */
+	/* fields filled by function in Materialize return mode: */
+	Tuplestorestate *setResult;	/* holds the complete returned tuple set */
+	TupleDesc	setDesc;		/* actual descriptor for returned tuples */
 } ReturnSetInfo;
 
 /* ----------------