bug#51132: Make sure user is doubly aware of finished complilations

[Kévin Le Gouguec]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: 積丹尼 Dan Jacobson <jidanni@jidanni.org>
>> Cc: 51132@debbugs.gnu.org
>> Date: Tue, 12 Oct 2021 16:04:04 +0800
>> 
>> EZ>   . I see "Compilation:exit" on the mode line (all of them)
>> 
>> Well in emacs-version "27.1" the Compilation:exit is only in the
>> *compilation* buffer's modeline. That's all I know.
>
> Which is great, and you should see it.

Unless the *compilation* buffer's mode-line is not visible, either
because of excessive window splitting (as hinted by Dan's other
message), or because one buried the buffer before the process
terminates, which one might very well do if it's a long-running process
with no interesting output except the final diagnosis.

(I'm confused by your earlier statement, when you say "all of them": do
you see "Compilation:exit" in the mode-line of *all* buffers?  On my
end, as Dan describes, that only shows up in the *compilation* buffer's
mode-line)

I think I can see how the current state of affairs makes it possible to
forget to check out a compilation result if the buffer is buried (or if
its mode-line is not completely visible):

- the "[Compiling]" mode-line indicator in other buffers disappears once
  the process terminates,

- the "Compilation finished/exited" message can be clobbered almost
  immediately by many things (e.g. navigation commands that push the
  mark, digit arguments, C-g).

Dan's suggestion to have (an option to have) an indicator in every
mode-line that disappears when you focus the *compilation* buffer makes
sense IMO.  It's not unlike erc-track's mode-line indicators AFAICT.