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Subject: Re: [PATCH] Fix wrong comment in JsonTablePlanJoinNextRow()
From: Chao Li <li.evan.chao@gmail.com>
In-Reply-To: <tencent_4CC6316F02DECA61ACCF22F933FEA5C12806@qq.com>
Date: Thu, 16 Apr 2026 10:05:08 +0800
Cc: pgsql-hackers <pgsql-hackers@lists.postgresql.org>
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Message-Id: <9EE922BD-29B2-40AF-A50E-03D7E89C10DB@gmail.com>
References: <tencent_4CC6316F02DECA61ACCF22F933FEA5C12806@qq.com>
To: =?utf-8?B?6IOh5Lyg5paH?= <463945512@qq.com>
Archived-At: 
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> On Apr 15, 2026, at 16:28, =E8=83=A1=E4=BC=A0=E6=96=87 =
<463945512@qq.com> wrote:
>=20
> Hi,
> Found a misleading comment in JsonTablePlanJoinNextRow() while reading
> the JSON_TABLE execution code.
> The function returns false when both siblings are exhausted (meaning =
no
> more rows), but the comment says "there are more rows" =E2=80=94 the =
exact
> opposite of what's happening. The code itself is correct.
> if (!JsonTablePlanNextRow(planstate->right))
> {
> /* Right sibling ran out of row, so there are more rows. */ /* wrong =
*/
> return false;
> }
> A reader might reasonably treat this as a bug and flip the return =
value,
> which would cause JSON_TABLE UNION plans to loop indefinitely.
> Patch attached.
> Regards,
> Chuanwen Hu<fix-jsontable-comment.patch>

The fix looks correct to me. I guess =E2=80=9Cno=E2=80=9D was just =
unintentionally missed.

A small comment, I just feel =E2=80=9Ctoo=E2=80=9D you newly added might =
not be needed.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/