From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tatsuo Ishii <ishii@postgresql.org>
cc: ojford@gmail.com, peter@eisentraut.org, li.evan.chao@gmail.com,
        krasiyan@gmail.com, vik@postgresfriends.org,
        andrew@tao11.riddles.org.uk, david@fetter.org,
        pgsql-hackers@lists.postgresql.org
Subject: Re: Add RESPECT/IGNORE NULLS and FROM FIRST/LAST options
In-reply-to: <20251003.100606.2086363717963832725.ishii@postgresql.org>
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Comments: In-reply-to Tatsuo Ishii <ishii@postgresql.org>
	message dated "Fri, 03 Oct 2025 10:06:06 +0900"
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Date: Sun, 05 Oct 2025 11:59:17 -0400
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Tatsuo Ishii <ishii@postgresql.org> writes:
> I have just pushed the patch (plus patches for syntax.sgml and
> sql_features.txt. They were missued after I splitted the patch).

Coverity is not very happy with this patch.
It's complaining that the result of window_gettupleslot
is not checked, which seems valid:

1503     			{
1504     				if (fetch_tuple)
>>>     CID 1666587:         Error handling issues  (CHECKED_RETURN)
>>>     Calling "window_gettupleslot" without checking return value (as is=
 done elsewhere 8 out of 9 times).
1505     					window_gettupleslot(winobj, pos, slot);
1506     				if (!are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot)=
)
1507     					return -1;

and also that WinGetFuncArgInPartition is dereferencing
a possibly-null "isout" pointer at several places, including

>>>     Dereferencing null pointer "isout".
3806     				if (*isout)		/* out of partition? */

>>>     Dereferencing null pointer "isout".
3817     	if (!*isout && set_mark)
3818     		WinSetMarkPosition(winobj, abs_pos);

>>>     Dereferencing null pointer "isout".
3817     	if (!*isout && set_mark)
3818     		WinSetMarkPosition(winobj, abs_pos);

The latter complaints seem to be because some places in
WinGetFuncArgInPartition check for nullness of that pointer
and some do not.  That looks like at least a latent bug
to me.  If it isn't, the function's comment needs to be
expanded to say when it's legal to pass isout =3D=3D NULL.

			regards, tom lane