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 976246f67480c5279c1f2334c4cbde38b7a148c3..6c9062f98880b891c6eb96629e6a73f7608fe7cf 100644 (file)
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.202 2008/01/01 19:46:00 momjian Exp $
+ *       $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.202.2.1 2008/09/01 22:30:40 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -4296,13 +4296,27 @@ 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);
@@ -4314,24 +4328,12 @@ 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;
 
@@ -4363,6 +4365,7 @@ exec_move_row(PLpgSQL_execstate *estate,
         */
        if (row != NULL)
        {
+               int                     td_natts = tupdesc ? tupdesc->natts : 0;
                int                     t_natts;
                int                     fnum;
                int                     anum;
@@ -4385,12 +4388,18 @@ 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++;
                        }