From: Tom Lane <tgl@sss.pgh.pa.us>
To: Yura Sokolov <y.sokolov@postgrespro.ru>
cc: pgsql-hackers@lists.postgresql.org
Subject: Re: When IMMUTABLE is not.
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Comments: In-reply-to Yura Sokolov <y.sokolov@postgrespro.ru>
	message dated "Thu, 15 Jun 2023 13:22:28 +0300"
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Date: Thu, 15 Jun 2023 09:21:38 -0400
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Yura Sokolov <y.sokolov@postgrespro.ru> writes:
> I found, than declaration of function as IMMUTABLE/STABLE is not enough =
to be sure
> function doesn't manipulate data.

Of course not.  It is the user's responsibility to mark functions
properly.  Trying to enforce that completely is a fool's errand;
you soon get into trying to solve the halting problem.

I don't like anything about the proposed patch.  It's necessarily
only a partial solution, and it probably breaks cases that are
perfectly safe in context.

			regards, tom lane