Feedback-ID: id4a34324:Fastmail
Date: Sun, 25 Jan 2026 15:06:12 -0500
From: Andres Freund <andres@anarazel.de>
To: Jelte Fennema-Nio <postgres@jeltef.nl>
Cc: Peter Eisentraut <peter@eisentraut.org>, 
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Thomas Munro <thomas.munro@gmail.com>
Subject: Re: Make copyObject work in C++
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Hi,

On 2026-01-25 18:52:37 +0100, Jelte Fennema-Nio wrote:
> On Sun Jan 25, 2026 at 5:50 PM CET, Andres Freund wrote:
> > We were going for designated
> > initializers for a reason, namely that we expect more arguments to be added
> > over time and perhaps eventually also to remove some. And this will just lead
> > to that being harder because we have to worry about C++ extensions.
> 
> Adding new arguments (aka fields) should cause no problems. Assuming
> we'd add them at the end of the Pg_magic_struct definition. Removing
> ones seems like even for C you'd need different PG_MODULE_MAGIC_EXT
> invocations depending on PG_VERSION_NUM. I don't see how using
> positional args would make that harder.

Named args make that easier in two ways: First, only extensions using the
to-be-removed option will fail. Second, removal of options reliably generates
errors, rather than bogusly use one field for another, just because the types
are compatible.

Greetings,

Andres Freund