Re: Tramp hangs when used with ESS

[Michael Albinus]

"Guha, Rishab" <address@hidden> writes:

> Hi,

Hi Rishab,

> Tramp has been hanging on 'Sending password' for me whenever I try to
> use it. This includes the simplest test case of C-x C-f
> /sudo::/etc/hosts.
>
> After some trial-and-error with my .emacs, it looks like the problem
> occurs if and only if ESS is active. Unfortunately, I haven't been
> able to figure out anything more than that. Debug log output from the
> simplest possible test case, with init.el looking like
> http://pastebin.com/WVq9TTdA, is here: http://pastebin.com/XJp7abc3
>
> I haven't found any way of replicating this without activating ESS.
> Note that though the message log says that Tramp is sending a
> password, I was never prompted to enter a password--the minibuffer
> proceeded directly to 'Sending password'

I couldn't reproduce it locally, even after installing ess 20160825.413
from melpa. Looking at the traces, your password is sent indeed several
times:

--8<---------------cut here---------------start------------->8---
11:30:06.340081 tramp-maybe-open-connection (6) # /bin/sh -i
11:30:06.344354 tramp-wait-for-regexp (6) # 
#$ 
11:30:06.370876 tramp-send-command (6) # exec env SHELL=/bin/sh sudo -u root -s 
-H -p P""a""s""s""w""o""r""d"":
11:30:06.389828 tramp-accept-process-output (10) # *tramp/sudo address@hidden 
run *tramp/sudo address@hidden
Password:
11:30:06.480065 tramp-accept-process-output (10) # *tramp/sudo address@hidden 
run *tramp/sudo address@hidden

Sorry, try again.
Password:
11:30:07.481634 tramp-accept-process-output (10) # *tramp/sudo address@hidden 
run *tramp/sudo address@hidden

Sorry, try again.
Password:
11:30:07.773566 tramp-file-name-handler (1) # Interrupt received in operation 
(file-exists-p /sudo:address@hidden:/DESCRIPTION)

Sorry, try again.
Password:
--8<---------------cut here---------------end--------------->8---

We must try to find out which password was sent silently. You might set
the following:

(trace-function-background 'tramp-read-passwd)

Then you will get a buffer *trace-output* with a content like this:

--8<---------------cut here---------------start------------->8---
1 -> (tramp-read-passwd #<process *tramp/sudo address@hidden>)
1 <- tramp-read-passwd: "secret"
--8<---------------cut here---------------end--------------->8---

I've used the password "secret" in this case; you might see something
else. DON'T send the output somewhere, but maybe it helps you to see
where the password comes from.

I've seen also some strange Tramp usage in the ess code, but this might
not be related. We'll investigate if needed.

> Best,
>
> Rishab

Best regards, Michael.