Fix plpgsql's exec_move_row() to supply valid type OIDs to exec_assign_value()

whenever possible, as per bug report from Oleg Serov.  While at it, reorder
the operations in the RECORD case to avoid possible palloc failure while the
variable update is only partly complete.

Back-patch as far as 8.1.  Although the code of the particular function is
similar in 8.0, 8.0's support for composite fields in rows is sufficiently
broken elsewhere that it doesn't seem worth fixing this.

diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 6bc97eaa5c457810709e2f3601b7c5ef16d02918..a3e876744924bc9b3f8a49fd25f0620c2cca2bdc 100644 (file)
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -3,7 +3,7 @@
  *                       procedural language
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.154.2.6 2007/02/08 18:37:55 tgl Exp $
+ *       $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.154.2.7 2008/09/01 22:30:55 tgl Exp $
  *
  *       This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -3915,13 +3915,27 @@ exec_move_row(PLpgSQL_execstate *estate,
        if (rec != NULL)
        {
                /*
-                * copy input first, just in case it is pointing at variable's value
+                * Copy input first, just in case it is pointing at variable's value
                 */
                if (HeapTupleIsValid(tup))
                        tup = heap_copytuple(tup);
+               else if (tupdesc)
+               {
+                       /* If we have a tupdesc but no data, form an all-nulls tuple */
+                       char       *nulls;
+
+                       nulls = (char *) palloc(tupdesc->natts * sizeof(char));
+                       memset(nulls, 'n', tupdesc->natts * sizeof(char));
+
+                       tup = heap_formtuple(tupdesc, NULL, nulls);
+
+                       pfree(nulls);
+               }
+
                if (tupdesc)
                        tupdesc = CreateTupleDescCopy(tupdesc);
 
+               /* Free the old value ... */
                if (rec->freetup)
                {
                        heap_freetuple(rec->tup);
@@ -3933,24 +3947,12 @@ exec_move_row(PLpgSQL_execstate *estate,
                        rec->freetupdesc = false;
                }
 
+               /* ... and install the new */
                if (HeapTupleIsValid(tup))
                {
                        rec->tup = tup;
                        rec->freetup = true;
                }
-               else if (tupdesc)
-               {
-                       /* If we have a tupdesc but no data, form an all-nulls tuple */
-                       char       *nulls;
-
-                       nulls = (char *) palloc(tupdesc->natts * sizeof(char));
-                       memset(nulls, 'n', tupdesc->natts * sizeof(char));
-
-                       rec->tup = heap_formtuple(tupdesc, NULL, nulls);
-                       rec->freetup = true;
-
-                       pfree(nulls);
-               }
                else
                        rec->tup = NULL;
 
@@ -3982,6 +3984,7 @@ exec_move_row(PLpgSQL_execstate *estate,
         */
        if (row != NULL)
        {
+               int                     td_natts = tupdesc ? tupdesc->natts : 0;
                int                     t_natts;
                int                     fnum;
                int                     anum;
@@ -4004,12 +4007,18 @@ exec_move_row(PLpgSQL_execstate *estate,
 
                        var = (PLpgSQL_var *) (estate->datums[row->varnos[fnum]]);
 
-                       while (anum < t_natts && tupdesc->attrs[anum]->attisdropped)
+                       while (anum < td_natts && tupdesc->attrs[anum]->attisdropped)
                                anum++;                 /* skip dropped column in tuple */
 
-                       if (anum < t_natts)
+                       if (anum < td_natts)
                        {
-                               value = SPI_getbinval(tup, tupdesc, anum + 1, &isnull);
+                               if (anum < t_natts)
+                                       value = SPI_getbinval(tup, tupdesc, anum + 1, &isnull);
+                               else
+                               {
+                                       value = (Datum) 0;
+                                       isnull = true;
+                               }
                                valtype = SPI_gettypeid(tupdesc, anum + 1);
                                anum++;
                        }