bug#30213: 26.0.91; shell buffer not displayed when not erased and async-shell-command-display-buffer is used

[Alex Branham]

I'm sorry, haven't had my morning coffee yet. I can reproduce this, but there 
was an error in my initial email. From emacs -Q

(setq shell-command-dont-erase-buffer 'beg-last-out
      async-shell-command-display-buffer nil)

then do an async shell command, delete the window that shows the output, then 
call another async shell command. The window is never re-shown.

Alex

On Tue 23 Jan 2018 at 08:53, Alex Branham <alex.branham@gmail.com> wrote:

> Rebuilding Emacs from the latest commit on the emacs-26 branch seems to have 
> solved the issue, whatever it was.
>
> Thanks!
>
> On Mon 22 Jan 2018 at 18:23, Basil L. Contovounesios <contovob@tcd.ie> wrote:
>
>> Alex Branham <alex.branham@gmail.com> writes:
>>
>>> With async-shell-command-display-buffer set to t and
>>> shell-command-dont-erase-buffer set to 'beg-last-output, async shell
>>> buffers do not get displayed after the second async call, presumably
>>> because the buffer doesn't get erased so there isn't a first line
>>> written.
>>
>> Just to clarify: are you setting shell-command-dont-erase-buffer to
>> beg-last-output or beg-last-out?  The former isn't a valid value for
>> this user option.
>>
>> Either way, I cannot reproduce what I think you are doing in a build of
>> today's master branch, but I think it would help if you listed the
>> precise steps leading to the output buffer failing to display.
>>
>> Thanks,