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++;
    }