From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Jonathan S. Katz" <jkatz@postgresql.org>
cc: Michael Paquier <michael@paquier.xyz>,
 David Rowley <dgrowleyml@gmail.com>,
        exclusion@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18240: Undefined behaviour in cash_mul_flt8() and friends
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Comments: In-reply-to "Jonathan S. Katz" <jkatz@postgresql.org>
	message dated "Fri, 12 Jan 2024 11:19:08 -0500"
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Date: Fri, 12 Jan 2024 11:33:18 -0500
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"Jonathan S. Katz" <jkatz@postgresql.org> writes:
> On 1/10/24 8:12 PM, Michael Paquier wrote:
>> While looking at the whole picture, an issue with the direct removal
>> of money is how we should handle btree_gin and btree_gist which have
>> operators based on money.  We try to keep things compatible at
>> run-time, but could this be worth a hard break in these modules,
>> dropping the older sql scripts used in the modules if we don't have
>> access to money anymore at runtime?  These are not popular modules..
>> Any thoughts about that?

> Both modules are pretty popular.

Yeah, I think it's a serious error to assume they aren't used plenty.
Not the money part, but other scalar types.

> It sounds like we'd have to tread a bit lightly because of this, even if 
> money is not frequently (or at all) used with btree_gist/gin?

What'd have to happen is that people would have to upgrade to a
version of btree_gin/btree_gist that deletes its money support
before they could pg_upgrade into a core version that lacks money.
So we'd have to ship that version at least one major release before
nuking the core support.

I think the shortest timeline we could possibly do this on is:

v17: label money as deprecated and due for removal in the SGML docs

v18: remove support in btree_gin/btree_gist (and any other affected
extensions)

v19: remove it from core

Note that in v18, people could still use money even in
btree_gin/btree_gist, just by installing a non-default extension
version.  So their C code for money would have to stay.

			regards, tom lane