Allow the return value of an SQL function to be binary-compatible with

the declared result type, rather than requiring exact type match as
before.  Per pghackers discusssion of 14-Aug.

diff --git a/src/backend/catalog/pg_proc.c b/src/backend/catalog/pg_proc.c
index cdfe8bfb2495d4767e661e1b5098c86183da468b..e285e435a34c447c53b0c4efa531868556b6561f 100644 (file)
--- a/src/backend/catalog/pg_proc.c
+++ b/src/backend/catalog/pg_proc.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/catalog/pg_proc.c,v 1.57 2001/08/10 15:49:39 petere Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/catalog/pg_proc.c,v 1.58 2001/08/23 00:49:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -22,6 +22,7 @@
 #include "catalog/pg_type.h"
 #include "executor/executor.h"
 #include "miscadmin.h"
+#include "parser/parse_coerce.h"
 #include "parser/parse_expr.h"
 #include "parser/parse_type.h"
 #include "tcop/tcopprot.h"
@@ -332,7 +333,7 @@ checkretval(Oid rettype, List *queryTreeList)
        List       *tlistitem;
        int                     tlistlen;
        Oid                     typerelid;
-       Resdom     *resnode;
+       Oid                     restype;
        Relation        reln;
        Oid                     relid;
        int                     relnatts;
@@ -377,6 +378,7 @@ checkretval(Oid rettype, List *queryTreeList)
        /*
         * For base-type returns, the target list should have exactly one
         * entry, and its type should agree with what the user declared.
+        * (As of Postgres 7.2, we accept binary-compatible types too.)
         */
        typerelid = typeidTypeRelid(rettype);
        if (typerelid == InvalidOid)
@@ -385,25 +387,25 @@ checkretval(Oid rettype, List *queryTreeList)
                        elog(ERROR, "function declared to return %s returns multiple columns in final SELECT",
                                 format_type_be(rettype));
 
-               resnode = (Resdom *) ((TargetEntry *) lfirst(tlist))->resdom;
-               if (resnode->restype != rettype)
+               restype = ((TargetEntry *) lfirst(tlist))->resdom->restype;
+               if (restype != rettype && !IS_BINARY_COMPATIBLE(restype, rettype))
                        elog(ERROR, "return type mismatch in function: declared to return %s, returns %s",
-                         format_type_be(rettype), format_type_be(resnode->restype));
+                                format_type_be(rettype), format_type_be(restype));
 
                return;
        }
 
        /*
         * If the target list is of length 1, and the type of the varnode in
-        * the target list is the same as the declared return type, this is
-        * okay.  This can happen, for example, where the body of the function
-        * is 'SELECT (x = func2())', where func2 has the same return type as
+        * 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)
        {
-               resnode = (Resdom *) ((TargetEntry *) lfirst(tlist))->resdom;
-               if (resnode->restype == rettype)
+               restype = ((TargetEntry *) lfirst(tlist))->resdom->restype;
+               if (restype == rettype || IS_BINARY_COMPATIBLE(restype, rettype))
                        return;
        }
 
@@ -427,15 +429,17 @@ checkretval(Oid rettype, List *queryTreeList)
        {
                TargetEntry *tle = (TargetEntry *) lfirst(tlistitem);
                Oid                     tletype;
+               Oid                     atttype;
 
                if (tle->resdom->resjunk)
                        continue;
                tletype = exprType(tle->expr);
-               if (tletype != reln->rd_att->attrs[i]->atttypid)
+               atttype = reln->rd_att->attrs[i]->atttypid;
+               if (tletype != atttype && !IS_BINARY_COMPATIBLE(tletype, atttype))
                        elog(ERROR, "function declared to return %s returns %s instead of %s at column %d",
                                 format_type_be(rettype),
                                 format_type_be(tletype),
-                                format_type_be(reln->rd_att->attrs[i]->atttypid),
+                                format_type_be(atttype),
                                 i + 1);
                i++;
        }