From: Tom Lane <tgl@sss.pgh.pa.us>
To: Maciek Sakrejda <m.sakrejda@gmail.com>
cc: Justin Pryzby <pryzby@telsasoft.com>, Robert Haas <robertmhaas@gmail.com>,
        "David G. Johnston" <david.g.johnston@gmail.com>,
        Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: warn if GUC set to an invalid shared library
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Comments: In-reply-to Maciek Sakrejda <m.sakrejda@gmail.com>
	message dated "Mon, 14 Feb 2022 10:12:22 -0800"
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Date: Wed, 23 Mar 2022 15:02:23 -0400
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Maciek Sakrejda <m.sakrejda@gmail.com> writes:
> In v4, the message looks fine to me for shared_preload_libraries
> (except there is a doubled "is"). However, I also get the message for
> a simple SET with local_preload_libraries:

> postgres=# set local_preload_libraries=xyz;
> WARNING:  could not access file "xyz"
> HINT:  The server will fail to start with the existing configuration.
> If it is is shut down, it will be necessary to manually edit the
> postgresql.auto.conf file to allow it to start.
> SET

I agree with Maciek's concerns about these HINTs being emitted
inappropriately, but I also have a stylistic gripe: they're only
halfway hints.  Given that we fix things so they only print when they
should, the complaint about the server not starting is not a hint,
it's a fact, which per style guidelines means it should be errdetail.
So I think this ought to look more like

WARNING:  could not access file "xyz"
DETAIL:  The server will fail to start with this setting.
HINT:  If the server is shut down, it will be necessary to manually edit the
postgresql.auto.conf file to allow it to start again.

I adjusted the wording a bit too --- YMMV, but I think my text is clearer.

			regards, tom lane