Michael Albinus <michael.albinus@gmx.de> writes:

Hi Dmitry,
>
>> So it seems to me that fixing shell-mode would be good for the default
>> behavior, and then one could use tramp-histfile-override to add extra
>> performance on top.
>
> I'll see whether I could make it more fine-grained, for example by
> distinguishing the shell and shell-command cases.

I've puzzled the appended patch together. It does the following:

- Obey 'tramp-histfile-override' also for direct async processes.

- Use 'tramp-histfile-override' in 'shell-mode', whether the remote
  history file shall be read. A value of t suppresses this.

- Support connection-local setting of 'tramp-histfile-override' in
  'shell'. Use something like

--8<---------------cut here---------------start------------->8---
  (connection-local-set-profile-variables
   'remote-tramp-histfile-override '((tramp-histfile-override . nil)))

  (connection-local-set-profiles
   '(:application tramp :machine "remotehost")
   'remote-tramp-histfile-override)
--8<---------------cut here---------------end--------------->8---

- Support connection-local setting of 'tramp-histfile-override' in
  'shell-command'. In order to distinguish this from the setting for
  'shell', another :application is used ('shell-command' instead of
  'tramp'). Use something like

--8<---------------cut here---------------start------------->8---
  (connection-local-set-profile-variables
   'another-tramp-histfile-override '((tramp-histfile-override . t)))

  (connection-local-set-profiles
   '(:application shell-command :machine "remotehost")
   'another-tramp-histfile-override)
--8<---------------cut here---------------end--------------->8---

It is recommended to set 'tramp-histfile-override' to t for
asynchronous processes. Comments?

Best regards, Michael.