bug#35506: 27.0.50; Emacs hangs while interrupting tramp processes

[Michael Albinus <michael.albinus@gmx.de>]

John Shahid <jvshahid@gmail.com> writes:

Hi John,

> It looks like the first issue can be solved by killing the entire
> process group, but I am not sure how safe it is to always do that.  I
> will attach a patch that I use locally which seem harmless so far.

Reading the Emacs manual again at (info "(elisp) Signals to Processes")

--8<---------------cut here---------------start------------->8---
If CURRENT-GROUP is ‘nil’, the signal is sent to the process group of
the immediate subprocess of Emacs.
--8<---------------cut here---------------end--------------->8---

So your patch is correct, pls push.

> The second issue can be solved by not waiting for the process to exit.
> This seems to be in line with the contract of `interrupt-process'.  I
> will attach a patch to remove the wait.

No, Tramp must report success. See the Emacs manual, same location as
above:

--8<---------------cut here---------------start------------->8---
 -- Variable: interrupt-process-functions
     This variable is a list of functions to be called for
     ‘interrupt-process’.  The arguments of the functions are the same
     as for ‘interrupt-process’.  These functions are called in the
     order of the list, until one of them returns non-‘nil’.  The
     default function, which shall always be the last in this list, is
     ‘internal-default-interrupt-process’.

     This is the mechanism, how Tramp implements ‘interrupt-process’.
--8<---------------cut here---------------end--------------->8---

So we must investigate, why `interrupt-process' does not return in your case.

Best regards, Michael.

PS: In the FSF list, your email address is given as <vshahid@gmail.com>.
Looks like a typo, maybe you contact the FSF clerk about.