Subject: bug#31357: 26.1; tramp-make-tramp-file-name: incompatible lisp changes in 26.1 ?

From: Phil Sainty <[email-masked]>
Date: Fri, 04 May 2018 02:23:45 +1200

In Emacs 25 `tramp-make-tramp-file-name' takes 4-5 arguments:
(method user host localname &optional hop)

In Emacs 26.1 it takes 6-7
(method user domain host port localname &optional hop)

That can then trigger a "wrong-number-of-arguments" error.

This should surely be covered in NEWS under the "Incompatible Lisp
Changes in Emacs 26.1" section?

I rather suspect there were also many other functions affected by
these changes, but I've not attempted to audit that.

I have custom code where I am presently using the following construct
to deal with this.

(if (version< emacs-version "26")
     (tramp-make-tramp-file-name
      method user host localname hop)
   (tramp-make-tramp-file-name
    method user domain host port localname hop))

(With a consequential complaint from the 26.1 byte-compiler about
the first of those two calls.)

Is there a single approach which is backwards-compatible (at least with
Emacs 25) ?

For my specific use-case, what I really wanted was a way to modify only
a specific named component of a tramp file name, but I ended up using
`tramp-dissect-file-name', extracting the components with the various
`tramp-file-name-COMPONENT' functions, and using `tramp-make-file-name'
to put it all back together.  I thought there might be a simpler way to
do this, but I didn't see one.

-Phil

In GNU Emacs 26.1 (build 1, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll 
bars)
  of 2018-04-15 built on shodan
Windowing system distributor 'The X.Org Foundation', version 
11.0.11804000
System Description:	Ubuntu 16.04.4 LTS

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