bug#20634: 25.0.50; Conflict between Tramp and EasyPG

[Michael Albinus]

Jens Lechtenboerger <jens.lechtenboerger@fsfe.org> writes:

> Hi there,

Hi Jens,

> I use EasyPG for transparent access of encrypted files with
> extension .gpg.  If I copy an encrypted file, say test.gpg, via ssh
> (Tramp) to a remote location, then I’m asked what public key to use
> for encryption (none for symmetric encryption), and the encrypted
> file is encrypted again, rendering it useless from within Emacs.
> (If I open the remote file via Tramp, the outer layer of encryption
> is removed, and I see the original encrypted file.)

Thanks for the report; I could reproduce the problem using your
recipe. Could you, please, check whether the following patch fixes the
problem?

--8<---------------cut here---------------start------------->8---
*** /home/albinus/src/tramp/lisp/tramp-sh.el.~master~   2015-05-24 
18:17:53.333961247 +0200
--- /home/albinus/src/tramp/lisp/tramp-sh.el    2015-05-24 18:13:15.299684599 
+0200
***************
*** 2122,2136 ****
  KEEP-DATE is non-nil if NEWNAME should have the same timestamp as FILENAME."
    ;; We must disable multibyte, because binary data shall not be
    ;; converted.  We don't want the target file to be compressed, so we
!   ;; let-bind `jka-compr-inhibit' to t.
!   ;; We remove `tramp-file-name-handler' from
    ;; `inhibit-file-name-handlers'; otherwise the file name handler for
    ;; `insert-file-contents' might be deactivated in some corner cases.
    (let ((coding-system-for-read 'binary)
        (coding-system-for-write 'binary)
        (jka-compr-inhibit t)
        (inhibit-file-name-handlers
!        (remq 'tramp-file-name-handler inhibit-file-name-handlers)))
      (with-temp-file newname
        (set-buffer-multibyte nil)
        (insert-file-contents-literally filename)))
--- 2122,2137 ----
  KEEP-DATE is non-nil if NEWNAME should have the same timestamp as FILENAME."
    ;; We must disable multibyte, because binary data shall not be
    ;; converted.  We don't want the target file to be compressed, so we
!   ;; let-bind `jka-compr-inhibit' to t.  `epa-file-handler' shall not
!   ;; be called either.  We remove `tramp-file-name-handler' from
    ;; `inhibit-file-name-handlers'; otherwise the file name handler for
    ;; `insert-file-contents' might be deactivated in some corner cases.
    (let ((coding-system-for-read 'binary)
        (coding-system-for-write 'binary)
        (jka-compr-inhibit t)
        (inhibit-file-name-handlers
!        (cons epa-file-handler
!              . (remq 'tramp-file-name-handler inhibit-file-name-handlers))))
      (with-temp-file newname
        (set-buffer-multibyte nil)
        (insert-file-contents-literally filename)))
***************
*** 3205,3211 ****
         (if (fboundp 'find-buffer-file-type)
             (symbol-function 'find-buffer-file-type)
           nil))
!       (inhibit-file-name-handlers '(jka-compr-handler image-file-handler))
        (inhibit-file-name-operation 'insert-file-contents))
      (unwind-protect
        (progn
--- 3206,3213 ----
         (if (fboundp 'find-buffer-file-type)
             (symbol-function 'find-buffer-file-type)
           nil))
!       (inhibit-file-name-handlers
!        '(epa-file-handler image-file-handler jka-compr-handler))
        (inhibit-file-name-operation 'insert-file-contents))
      (unwind-protect
        (progn
--8<---------------cut here---------------end--------------->8---

> Note also that if I copy a plaintext file (test.txt) locally to one
> with gpg extension (test.gpg), it remains a plaintext file.  If I
> copy that to a remote location, it gets encrypted.  This may be a
> bug or a feature, but is certainly inconsistent behavior.

It is rather a feature (a copy operation shall not change the file
contents). The above patch shall fix this as well.

> Best wishes
> Jens

Best regards, Michael.