Fix Coverity issues reported in commit 25a30bbd423.

Fix several issues pointed out by Coverity (reported by Tome Lane).

- In row_is_in_frame(), return value of window_gettupleslot() was not
  checked.

- WinGetFuncArgInPartition() tried to derefference "isout" pointer
  even if it could be NULL in some places.

Besides the issues, I also fixed a compiler warning reported by Álvaro
Herrera.

Moreover, in WinGetFuncArgInPartition refactor the do...while loop so
that the codes inside the loop simpler. Also simplify the case when
abs_pos < 0.

Author: Tatsuo Ishii <[email protected]>
Reviewed-by: Paul Ramsey <[email protected]>
Reported-by: Tom Lane <[email protected]>
Reported-by: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/1686755.1759679957%40sss.pgh.pa.us
Discussion: https://postgr.es/m/202510051612.gw67jlc2iqpw%40alvherre.pgsql

diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index cf667c81211402230969c8cc221e9581f0626201..0698aae37a7e4033f41699dfde43833c231741ce 100644 (file)
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -1501,8 +1501,9 @@ row_is_in_frame(WindowObject winobj, int64 pos, TupleTableSlot *slot,
            /* following row that is not peer is out of frame */
            if (pos > winstate->currentpos)
            {
-               if (fetch_tuple)
-                   window_gettupleslot(winobj, pos, slot);
+               if (fetch_tuple)    /* need to fetch tuple? */
+                   if (!window_gettupleslot(winobj, pos, slot))
+                       return -1;
                if (!are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot))
                    return -1;
            }
@@ -3721,6 +3722,7 @@ WinGetFuncArgInPartition(WindowObject winobj, int argno,
    int         notnull_offset;
    int         notnull_relpos;
    int         forward;
+   bool        myisout;
 
    Assert(WindowObjectIsValid(winobj));
    winstate = winobj->winstate;
@@ -3759,63 +3761,60 @@ WinGetFuncArgInPartition(WindowObject winobj, int argno,
 
    if (!null_treatment)        /* IGNORE NULLS is not specified */
    {
+       /* get tupple and evaluate in a partition */
        datum = gettuple_eval_partition(winobj, argno,
-                                       abs_pos, isnull, isout);
-       if (!*isout && set_mark)
+                                       abs_pos, isnull, &myisout);
+       if (!myisout && set_mark)
            WinSetMarkPosition(winobj, abs_pos);
+       if (isout)
+           *isout = myisout;
        return datum;
    }
 
+   myisout = false;
+   datum = 0;
+
    /*
     * Get the next nonnull value in the partition, moving forward or backward
     * until we find a value or reach the partition's end.
     */
    do
    {
+       int         nn_info;    /* NOT NULL info */
+
        abs_pos += forward;
-       if (abs_pos < 0)
-       {
-           /* out of partition */
-           if (isout)
-               *isout = true;
-           *isnull = true;
-           datum = 0;
+       if (abs_pos < 0)        /* apparently out of partition */
            break;
-       }
 
-       switch (get_notnull_info(winobj, abs_pos))
+       /* check NOT NULL cached info */
+       nn_info = get_notnull_info(winobj, abs_pos);
+       if (nn_info == NN_NOTNULL)  /* this row is known to be NOT NULL */
+           notnull_offset++;
+
+       else if (nn_info == NN_NULL)    /* this row is known to be NULL */
+           continue;           /* keep on moving forward or backward */
+
+       else                    /* need to check NULL or not */
        {
-           case NN_NOTNULL:    /* this row is known to be NOT NULL */
-               notnull_offset++;
-               if (notnull_offset >= notnull_relpos)
-               {
-                   /* prepare to exit this loop */
-                   datum = gettuple_eval_partition(winobj, argno,
-                                                   abs_pos, isnull, isout);
-               }
-               break;
-           case NN_NULL:       /* this row is known to be NULL */
-               if (isout)
-                   *isout = false;
-               *isnull = true;
-               datum = 0;
-               break;
-           default:            /* need to check NULL or not */
-               datum = gettuple_eval_partition(winobj, argno,
-                                               abs_pos, isnull, isout);
-               if (*isout)     /* out of partition? */
-                   return datum;
-
-               if (!*isnull)
-                   notnull_offset++;
-               /* record the row status */
-               put_notnull_info(winobj, abs_pos, *isnull);
+           /* get tupple and evaluate in a partition */
+           datum = gettuple_eval_partition(winobj, argno,
+                                           abs_pos, isnull, &myisout);
+           if (myisout)        /* out of partition? */
                break;
+           if (!*isnull)
+               notnull_offset++;
+           /* record the row status */
+           put_notnull_info(winobj, abs_pos, *isnull);
        }
    } while (notnull_offset < notnull_relpos);
 
-   if (!*isout && set_mark)
+   /* get tupple and evaluate in a partition */
+   datum = gettuple_eval_partition(winobj, argno,
+                                   abs_pos, isnull, &myisout);
+   if (!myisout && set_mark)
        WinSetMarkPosition(winobj, abs_pos);
+   if (isout)
+       *isout = myisout;
 
    return datum;
 }