Re: Error with tramp-archive-autoload-file-name-handler

[Felix Dietrich <felix.dietrich@sperrhaken.name>]

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Michael Heerdegen <michael_heerdegen@web.de> writes:

> Michael Albinus <michael.albinus@gmx.de> writes:
>
>> I cannot reproduce. The following works fine:
>>
>> […]
>
> You missed the TWICE part in my last message.  Just eval the above
> twice:
>
> $ emacs -Q -l tramp --eval "(add-to-list 'file-name-handler-alist
> (cons (tramp-archive-autoload-file-name-regexp)
> #'tramp-archive-autoload-file-name-handler))" --eval
> '(file-directory-p "/home/albinus/tmp/out.tar.xz/")'\
>                     --eval "(add-to-list 'file-name-handler-alist
> (cons (tramp-archive-autoload-file-name-regexp)
> #'tramp-archive-autoload-file-name-handler))" --eval
> '(file-directory-p "/home/albinus/tmp/out.tar.xz/")'
>
> Sorry, but that's the best recipe I can offer.  And I guess something
> like this is actually happening.  AFAIU, Tramp can call
> `tramp-register-archive-file-name-handler' several times - see
> tramp-archive.el line 394:

With Emacs 27.1, I ran the test in the attached script a couple of times
and could *not* reproduce your error.


[-- Attachment #2: Script to test the issue with tramp --]
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#!/bin/sh

# Usage: testscript ARCHIVE_PATH [COUNT]
#
# Start Emacs and test ‘file-directory-p’ on ARCHIVE_PATH.
#
# Each time before using ‘file-directory-p’, add
#
#     (cons (tramp-archive-autoload-file-name-handler)
#           #'tramp-archive-autoload-file-name-handler)
#
# to ‘file-name-handler-alist’.  ‘file-directory-p’ is called twice.
#
# Do this for COUNT times or just once if COUNT is not provided
#
# ARCHIVE_PATH defaults to
# ~/"src/emacs/test/lisp/net/tramp-archive-resources/foo.iso/".


# Emacs -nw switch: do not create a GUI frame.
nw=-nw

archive_path=${1:-~/"src/emacs/test/lisp/net/tramp-archive-resources/foo.iso/"}
if ! [ -e "$archive_path" ]
then
    printf '"%s" does not exist' "$archive_path" >&2
    exit 66 # EX_NOINPUT
fi
count=${2:-1}

run_emacs ()
{
  emacs $nw -Q -l tramp \
    --eval \
        '(setq command-error-function
               ;; Catch an error in a process filter.
               (lambda () (kill-emacs 1)))'                                \
    --eval \
        "(add-to-list 'file-name-handler-alist
                      (cons (tramp-archive-autoload-file-name-regexp)
                             #'tramp-archive-autoload-file-name-handler))" \
    --eval \
        '(let ((ret 2))
          (unwind-protect
              (setq ret (if (file-directory-p "'"$archive_path"'")
                          ;; either result counts as success
                          0 0))
            (kill-emacs ret)))'                                            \
    --eval \
        "(add-to-list 'file-name-handler-alist
                      (cons (tramp-archive-autoload-file-name-regexp)
  		                    #'tramp-archive-autoload-file-name-handler))"  \
    --eval \
        '(let ((ret 3))
          (unwind-protect
              (setq ret (if (file-directory-p "'"$archive_path"'")
                          ;; either result counts as success
                          0 0))
            (kill-emacs ret)))'
}


i=0
while [ "$i" -lt "$count" ]
do
    i=$(( i + 1 ))
    run_emacs
    ret=$?
	case $ret in
        0) # All good, just
           continue
           ;;
	    1) echo "‘command-error-function’ killed emacs" >&2
           exit $ret
           ;;
        2) echo "1. ‘unwind-protect’ killed emacs" >&2
           exit $ret
           ;;
		3) echo "2. ‘unwind-protect’ killed emacs" >&2
           exit $ret
           ;;
        *) echo "Unexpected return code: $ret" >&2
           exit $ret
           ;;
    esac
done

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-- 
Felix Dietrich