bug#35055: 27.0.50; async-shell-command truncates output lines

[Juri Linkov <juri@linkov.net>]

>>>> Note that for remote shell commands the situation is even worse, because
>>>> it sets the process property `adjust-window-size-function' to nil,
>>>> overwriting any setting in `window-adjust-process-window-size-function'.
>>>> This affects even synchronous `shell-command' calls, because they are
>>>> implemented Tramp internally as asynchronous process.
>>>
>>> I had truncated output of remote `shell-command' for a long time
>>> and thought that it's impossible to do anything with this,
>>> but now that you mentioned remote shell commands, I tried
>>> to affect their output with a quite large value of COLUMNS
>>> and get untruncated output even on remote.
>>
>> That's because Tramp sets process property `adjust-window-size-function'
>> to `ignore' (and not to nil as I wrote above). This was 2 years ago;
>> unfortunately, I have neither a bug nor a message reference for that change.
>
> Then I don't understand why remote shell output is limited to 80 columns
> when Tramp sets `adjust-window-size-function' to `ignore', i.e. not to 80.

We could add a new defcustom process-window-width with a choice of
a numeric value to set COLUMNS env variable in the process, or
a symbol `window-width' to set COLUMNS to the width of the output
buffer's window.  Then it will handle both asynchronous processes
and synchronous remote shell commands as well.