Date: Mon, 16 Feb 2026 20:20:43 -0800
From: Noah Misch <noah@leadboat.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Thomas Munro <thomas.munro@gmail.com>, ranvis@gmail.com,
	pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19406: substring(text) fails on valid UTF-8 toasted value
 in PostgreSQL 15.16
Message-ID: <20260217042043.99.noahmisch@microsoft.com>
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On Mon, Feb 16, 2026 at 01:21:45PM -0500, Tom Lane wrote:
> Noah Misch <noah@leadboat.com> writes:
> > Pushed as commit 9f4fd11
> 
> Various BF animals are complaining
> 
> varlena.c: In function 'text_substring':
> varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>   int32  E;    /* end position, exclusive */
>          ^
> 
> and I've also seen that locally depending on which gcc version and -O
> level I'm using.  Could we silence that?
> 
> 
>  bollworm      | 2026-02-16 09:32:03 | varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  camel         | 2026-02-16 09:32:30 | varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  chimaera      | 2026-02-16 11:40:29 | /home/debian/20-chimaera/buildroot/HEAD/pgsql.build/../pgsql/src/backend/utils/adt/varlena.c:739:5: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  comma         | 2026-02-16 14:55:48 | varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  conchuela     | 2026-02-16 15:20:01 | varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  flea          | 2026-02-16 09:31:52 | varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  krait         | 2026-02-16 09:50:17 | varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  pipit         | 2026-02-15 02:36:02 | varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  urocryon      | 2026-02-15 01:45:07 | varlena.c:739:5: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  wireworm      | 2026-02-16 15:20:49 | varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
>  ziege         | 2026-02-15 01:18:25 | varlena.c:590:9: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]

Thanks.  I've pushed commit 8cef93d.