bug#66246: ERC buffer is no longer visible

[Corwin Brust]

On Wed, Sep 27, 2023 at 3:35 PM BTD Master via Bug reports for GNU
Emacs, the Swiss army knife of text editors <bug-gnu-emacs@gnu.org>
wrote:
>
> When I login through M-x erc (have also tried erc-tls with the same
> results), the erc buffer is no longer visible. Emacs instead remains on
> the previous buffer (in my case *scratch*). This did not happen in
> previous versions.
>
> I'm able to open the buffer when prompted when exiting emacs, but I am
> not able to use it during the prompt state from C-x C-c.
>
> Version: Arch Linux Emacs 29.1-4
>
> Thanks.

Hi.  The on-join window handling behaviors saw some changes in 29.1
(ERC 5.5) and more are in progress for Emacs 30 (ERC 5.6-git on GNU
ELPA devel).  IIUC, this was motivated because "rolling buffers though
the active window" was seen as being a potential security hazard.

Please look at ERC NEWS file (M-x erc-news RET) and also the variable
'erc-interactive-display' which you almost certainly want to set up in
your Emacs configuration, going forward.  Once you review those let us
know if that clears things up or if you suspect there may be a bug
here.   If you do believe there's a bug it may be helpful to have the
full output produced by M-x report-emacs-bug  (ideally from a session
where you've minimally reproduced the problem, so starting from -Q or
such).

Corwin