I can confirm the latest build no longer causes me that problem.

It's not vterm's fault, it's mine.  I set `default-directory` like that
when spawning it, which I have just been getting away with for a long
time.  It seems up until now a lot of things have been tolerant of my
invalid local path, with empty, '.' or './' seemingly being treated like
'~' before now.

So I'll be fixing my code that created a badly formed default-directory as
well.

Thank you for your efforts!  I'm very glad to see Tramp is getting some
attention.  I love it and rely on it but it adds a lot of latency for me
with its extensive round trips when establishing connections (I have to ssh
via an AWS jumphost).





On Sat, Sep 10, 2022 at 7:49 AM Michael Albinus <michael.albinus@gmx.de>
wrote:

> James Ferguson <james@faff.org> writes:
>
> Hi James,
>
> > That's definitely what raises the error, though the comment implies to
> > me that it's unexpected/undesirable that it is triggered.
>
> Indeed. Your backtrace from the original report shows
>
> > Debugger entered--Lisp error: (file-error "File ‘.’ must be absolute")
> >   signal(file-error ("File ‘.’ must be absolute"))
> >   tramp-error((tramp-file-name "sshx" nil nil "4x02" nil "." nil)
> file-error "File `%s' must be absolute" ".")
> >   tramp-file-name-unify((tramp-file-name "sshx" nil nil "4x02" nil "."
> nil) ".")
> >   tramp-get-file-property((tramp-file-name "sshx" nil nil "4x02" nil "."
> nil) "." "file-truename")
> >   tramp-flush-file-properties((tramp-file-name "sshx" nil nil "4x02" nil
> "." nil) ".")
> >   tramp-flush-file-function()
> >   kill-buffer(#<buffer Terminal-4x02 volta@4x02 (10.0.154.60) - byobu>)
>
> We see, that `tramp-flush-file-properties' is called with
> `default-directory' "." in #<buffer Terminal-4x02 volta@4x02
> (10.0.154.60) - byobu>
>
> This is obviously an error, because the docstring of `default-directory'
> says
>
> --8<---------------cut here---------------start------------->8---
> Name of default directory of current buffer.
> It should be an absolute directory name; on GNU and Unix systems,
> these names start with ‘/’ or ‘~’ and end with ‘/’.
> --8<---------------cut here---------------end--------------->8---
>
> Perhaps you could report this to the maintainer of vterm.
>
> For the time being, I've pushed a fix to Emacs master which expands
> `default-directory' inside `tramp-flush-file-properties'. Could you,
> pls, check?
>
> Best regards, Michael.
>