Tramp connection fails with "timeout reached"

Question

I've been using tramp to edit remote files for a few years now, but suddenly it stopped working yesterday. I haven't changed anything relevant that I can think of. For testing, I tried opening a file on localhost with \C-x C-f /ssh:localhost:/home/terdon/test. That bring up the Waiting for prompts from remote shell... message and times out after about a minute with:

Timeout reached, see buffer '*tramp/ssh localhost*' for details

The *tramp/ssh localhost* is shown in the buffers menu but disappears as soon as I try to switch to it.

Details

• I am running GNU emacs 25.3.1 on Arch Linux.
• I have updated my system and the elpa packages I have installed.

• To rule out problems with the remote prompt, I have replaced my ~/.bashrc and ~/.profile with:

  $ cat ~/.bashrc
  PS1='$ '
  $ cat ~/.profile
  PS1='$ '
  

  Yes, my default shell is bash and no, I don't have a ~/.bash_profile.

• I have set up passwordless ssh to all the servers that I've tried and which used to work. Including localhost (ssh localhost works fine with no password).

• My .emacs file has (the full file can be found here: https://pastebin.com/QGgPE3SS):

  (setq tramp-default-method "sshx")
  (setq tramp-verbose 10)
  

• The contents of the *debug tramp/ssh localhost* buffer are here: https://pastebin.com/F6r6d5cN.

• I read Tramp: Waiting for prompts from remote shell... Sending command `exec ssh -e none bin' and added these lines to my ~/.ssh/config file:

  Host *
    ControlPath ~/.ssh/master-%r@%h:%p
    ControlMaster auto
    ControlPersist = no 
  

  However, despite that, as you can see in the output in the previous bullet point, I still get command-line line 0: Missing ControlPersist argument line. Is that an issue?

• Running the ssh command from tramp's log maually works fine:

  $ ssh -o ControlMaster=auto -o ControlPath='tramp.%C' -o ControlPersist=no -e none localhost
  Last login: Tue Apr 24 13:58:15 2018 from ::1
  $ 
  

• Trying the same thing after loading emacs with emacs -Q gives the same problem, so it isn't something to do with my ~/.emacs.

• I created a new user with default settings and tried as that user and it worked! So while emacs -Q doesn't solve the issue, running as a new user does! What could cause that?

What else can I check? How can I get my tramp back again?

Answer 1

This is an issue mentioned in the Emacs Wiki:

If you have Control-j mapped in your ~/.inputrc ... it can cause tramp to never finish recognizing the shell prompt.

For me, the problem went away when I conditionally defined C-j binding only for non-dumb terminals:

$if term=dumb
# skip
$else
Control-j: foo
$endif

Answer 2

It turns out the problem was a malformed ~/.inputrc file. I had been playing around with it while trying to answer a question over at Unix & Linux and had left this line:

Control-J: "$(date)"

Removing that line fixed my problem with tramp. I don't understand why the local ~/.inputrc would affect my remote shell (I also faced this problem when connecting to actual remote hosts, not only localhost), but apparently it did.