After transforming a CASE expr with a default argument,

delete the default argument from the node.  This prevents the executor
from spitting up on the untransformed argument expression.  Typical
failure was:
select (case f1 when 'val' then 'subst' else f1 end) from t1;
ERROR:  copyObject: don't know how to copy 704

diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 6de507bae04c387533e427a89472e4f9165ac66f..d23d7214a34bbb3c56e455e08891b2b2e1dbffcd 100644 (file)
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.40 1999/02/03 21:16:57 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.41 1999/04/18 17:35:51 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -345,9 +345,9 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
                foreach(args, c->args)
                {
                    w = lfirst(args);
-                   /* shorthand form was specified, so expand... */
                    if (c->arg != NULL)
                    {
+                       /* shorthand form was specified, so expand... */
                        A_Expr *a = makeNode(A_Expr);
                        a->oper = OP;
                        a->opname = "=";
@@ -358,6 +358,13 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
                    lfirst(args) = transformExpr(pstate, (Node *) w, precedence);
                }
 
+               /* It's not shorthand anymore, so drop the implicit argument.
+                * This is necessary to keep the executor from seeing an
+                * untransformed expression...
+                */
+               c->arg = NULL;
+
+               /* transform the default clause */
                if (c->defresult == NULL)
                {
                    A_Const *n = makeNode(A_Const);
@@ -365,9 +372,9 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
                    c->defresult = (Node *)n;
                }
                c->defresult = transformExpr(pstate, (Node *) c->defresult, precedence);
-               c->casetype = exprType(c->defresult);
 
                /* now check types across result clauses... */
+               c->casetype = exprType(c->defresult);
                ptype = c->casetype;
                pcategory = TypeCategory(ptype);
                foreach(args, c->args)