From: Tom Lane <tgl@sss.pgh.pa.us>
To: Heikki Linnakangas <hlinnaka@iki.fi>
cc: Michael Paquier <michael@paquier.xyz>,
        Alvaro Herrera <alvherre@alvh.no-ip.org>,
        pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Removing support for COPY FROM STDIN in protocol version 2
In-reply-to: <8a174f9b-59e4-e231-5b66-1f01b314882a@iki.fi>
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Comments: In-reply-to Heikki Linnakangas <hlinnaka@iki.fi>
	message dated "Thu, 04 Mar 2021 10:59:41 +0200"
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Date: Thu, 04 Mar 2021 11:11:39 -0500
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Heikki Linnakangas <hlinnaka@iki.fi> writes:
> On 04/03/2021 01:32, Tom Lane wrote:
>> I'm not sure where the extra newlines are coming from, and it seems
>> unlikely to be worth worrying over.  This behavior is good enough for me.

> fe-connect.c appends a newline for any errors in pre-3.0 format:

>> 		/*
>> 		 * The postmaster typically won't end its message with a
>> 		 * newline, so add one to conform to libpq conventions.
>> 		 */
>> 		appendPQExpBufferChar(&conn->errorMessage, '\n');

> That comment is wrong. The postmaster *does* end all its error messages 
> with a newline. This changed in commit 9b4bfbdc2c in 7.2.

Ah-hah, and the bit you show here came in with 2af360ed1, in 7.0.
I'm surprised though that we didn't notice that the newline was now
usually redundant.  This was a commonly taken code path until 7.4.

Anyway, your fix seems fine ... I wonder if we should back-patch it?

			regards, tom lane