In can_coerce_type, verify that a possible type-coercion function

actually returns the type it is named for.

diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
index f37082a87f58d0d4986d718630fcc17c330c481a..35312eaadf07a696543b2209987ed092d4b19cd3 100644 (file)
--- a/src/backend/parser/parse_coerce.c
+++ b/src/backend/parser/parse_coerce.c
@@ -8,13 +8,13 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.36 2000/03/16 06:35:07 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.37 2000/03/19 00:15:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
 
-
+#include "catalog/pg_proc.h"
 #include "optimizer/clauses.h"
 #include "parser/parse_coerce.h"
 #include "parser/parse_expr.h"
@@ -126,6 +126,12 @@ coerce_type(ParseState *pstate, Node *node, Oid inputTypeId,
 
        result = transformExpr(pstate, (Node *) n, EXPR_COLUMN_FIRST);
 
+       /* safety check that we got the right thing */
+       if (exprType(result) != targetTypeId)
+           elog(ERROR, "coerce_type: conversion function %s produced %s",
+                typeTypeName(targetType), 
+                typeidTypeName(exprType(result)));
+
        /*
         * If the input is a constant, apply the type conversion function
         * now instead of delaying to runtime.  (We could, of course,
@@ -163,6 +169,7 @@ can_coerce_type(int nargs, Oid *input_typeids, Oid *func_typeids)
 {
    int         i;
    HeapTuple   ftup;
+   Form_pg_proc pform;
    Oid         oid_array[FUNC_MAX_ARGS];
 
    /* run through argument list... */
@@ -221,9 +228,10 @@ can_coerce_type(int nargs, Oid *input_typeids, Oid *func_typeids)
                                   0);
        if (!HeapTupleIsValid(ftup))
            return false;
-       /*
-        * should also check the function return type just to be safe...
-        */
+       /* Make sure the function's result type is as expected, too */
+       pform = (Form_pg_proc) GETSTRUCT(ftup);
+       if (pform->prorettype != targetTypeId)
+           return false;
    }
 
    return true;