Encoding problem with Tramp

[Stefan Monnier <monnier@iro.umontreal.ca>]

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[ For Kai Großjohann and Michael Albinus, thanks to stupid mailers. ]


        Stefan



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From: Stefan Monnier <monnier@iro.umontreal.ca>
To: "Kai Gro\x1fFFFFFFjohann" <kai.grossjohann@gmx.net>, "Michael Albinus" <michael.albinus@gmx.de>
Subject: Encoding problem with Tramp
Date: Mon, 17 Mar 2008 16:15:32 -0400
Message-ID: <jwveja96ryq.fsf-monnier+emacs@gnu.org>


I recently noticed that my home page has emacs-mule encoding, even tho
it specifies latin-1.  It turns out that it's because I was editing it
via Tramp and that Tramp has a bug in this regard.
Using good ol' print statements, it turns out that
last-coding-system-used is modified in tramp-handle-write-region *after*
tramp-handle-write-region was careful to save&set it.

More specifically the code does:

	  ;; Make `last-coding-system-used' have the right value.
	  (when coding-system-used
	    (set 'last-coding-system-used coding-system-used))))

      ;; Set file modification time.
      (when (or (eq visit t) (stringp visit))
	(set-visited-file-modtime
	 ;; We must pass modtime explicitely, because filename can
	 ;; be different from (buffer-file-name), f.e. if
	 ;; `file-precious-flag' is set.
	 (nth 5 (file-attributes filename))))

so while the first 3 lines DTRT, the subsequent 7 lines (probably just
the call to file-attributes) set the last-coding-system-used back to
raw-text-unix.

I suggest to fix Tramp's file-attributes by wrapping a let around it
that preserves the value of last-coding-system-used.

If I fix it, then I get the same problem with the subsequent call to
tramp-set-file-uid-gid.

Maybe another way to fix those problem is to move the above 3 lines that
reset last-coding-system-used to the end of tramp-handle-write-region.

Although, the let-binding around tramp-handle-file-attributes seem to be
good in general, since file-attributes is normally not expected to
modify last-coding-system-used.


        Stefan