Date: Mon, 06 Oct 2025 18:34:39 +0900 (JST)
Message-Id: <20251006.183439.876014721998277138.ishii@postgresql.org>
To: tgl@sss.pgh.pa.us
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
From: Tatsuo Ishii <ishii@postgresql.org>
In-Reply-To: <20251006.085133.920304905412132984.ishii@postgresql.org>
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	<1686755.1759679957@sss.pgh.pa.us>
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> Thank you for the report!
> 
>> 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;
> 
> Yes, I forgot to check the return value of window_gettupleslot.
> 
>> 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.
> 
> Agreed.
> 
> Attached is a patch to fix the issue.

Please disregard the v1 patch. It includes a bug: If
WinGetFuncArgInPartition() is called with set_mark == true and isout
== NULL, WinSetMarkPosition() is not called by
WinGetFuncArgInPartition().

I will post v2 patch.

Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp