bug#28691: [PATCH] Add file name handler support for 'make-process' (Bug#28691)

[Michael Albinus]

Philipp Stephani <p.stephani2@gmail.com> writes:

Hi Philipp,

> +:file-handler FILE-HANDLER -- If FILE-HANDLER is non-nil, then search
> +for a file name handler for `default-directory'.

What happens, if no file name handler is found? Should there be a local
process then, or should this be ignored (returning nil)?

> +(ert-deftest make-process/file-handler ()
> +  "Check that the ‘:file-handler’ argument of ‘make-process’
> +works as expected."
> +  (let ((file-handler-calls 0))
> +    (cl-flet ((file-handler
> +               (&rest args)
> +               (should (equal default-directory "test-handler:/dir/"))
> +               (should (equal args '(make-process :name "name"
> +                                                  :command ("/bin/true")
> +                                                  :file-handler t)))
> +               (cl-incf file-handler-calls)
> +               'fake-process))
> +      (let ((file-name-handler-alist
> +             (cons (cons (rx bos "test-handler:") #'file-handler)
> +                   file-name-handler-alist))
> +            (default-directory "test-handler:/dir/"))
> +        (should (eq (make-process :name "name"
> +                                  :command '("/bin/true")
> +                                  :file-handler t)
> +                    'fake-process))
> +        (should (= file-handler-calls 1))))))

I would make a second test, that calling `make-process' w/o the
`:file-handler' argument returns the plain process #<process name>.

The third test is for using non-nil `:file-handler', w/o finding one.
This returns either a local process, or nil (see remark above).

I also miss documentation in the Elisp manual, nodes "Magic File Names"
and "Asynchronous Processes".

And of course, the implementation of a file name handler is missing in
tramp-adb.el, tramp-sh.el and tramp-smb.el.

Best regards, Michael.