--- Begin Message ---
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Subject: |
26.3; append-to-file does not work on nonexistent file over ssh |
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Date: |
Fri, 20 Mar 2020 17:14:16 -0400 |
Hi folks,
The append-to-file function (and the underlying write-region in append
mode) fails over ssh (via tramp) when applied to a nonexistent file. The
same invocation creates the file transparently when invoked locally.
I think tramp should create the file as in the local usage, if
possible. If this is not possible, the discrepancy should be documented
somewhere. (Apologies if it is documented somewhere; I tried to find it
and could not.)
The following (edited) eshell transcript demonstrates the behavior
(though it works the same in Lisp):
Welcome to the Emacs shell
> ~ $ ls
> ~ $ append-to-file "something" nil nonexistent.txt
> ~ $ cat nonexistent.txt
> something~ $
> ~ $
> ~ $ cd /ssh:remote:
> /ssh:remote:/home/user $ ls
> /ssh:remote:/home/user $ append-to-file "something" nil nonexistent.txt
> File ‘/ssh:remote:/home/user/nonexistent.txt’ not found on remote host
> /ssh:remote:/home/user $
> /ssh:remote:/home/user $ touch nonexistent.txt
> /ssh:remote:/home/user $
> /ssh:remote:/home/user $ append-to-file "something" nil nonexistent.txt
> /ssh:remote:/home/user $
> /ssh:remote:/home/user $ cat nonexistent.txt
> something/ssh:remote:/home/user $
In GNU Emacs 26.3 (build 1, x86_64-apple-darwin18.2.0, NS appkit-1671.20
Version 10.14.3 (Build 18D109))
of 2019-09-02 built on builder10-14.porkrind.org
Windowing system distributor 'Apple', version 10.3.1975
Configured using:
'configure --with-ns '--enable-locallisppath=/Library/Application
Support/Emacs/${version}/site-lisp:/Library/Application
Support/Emacs/site-lisp' --with-modules'
Configured features:
NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS NS MODULES THREADS
Important settings:
value of $LANG: en_US.UTF-8
locale-coding-system: utf-8-unix
Major mode: Eshell
Minor modes in effect:
shell-dirtrack-mode: t
tooltip-mode: t
global-eldoc-mode: t
electric-indent-mode: t
mouse-wheel-mode: t
tool-bar-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
blink-cursor-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
line-number-mode: t
transient-mark-mode: t
Load-path shadows:
None found.
Features:
(shadow sort mail-extr emacsbug message rmc puny seq dired
dired-loaddefs rfc822 mml mml-sec epa derived epg epg-config gnus-util
rmail rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils pp files-x tramp-cache tramp-sh tramp
tramp-compat tramp-loaddefs trampver shell parse-time format-spec advice
auth-source cl-seq eieio byte-opt bytecomp byte-compile cconv eieio-core
cl-macs gv eieio-loaddefs password-cache pcmpl-unix em-unix em-term term
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em-hist em-pred em-glob em-dirs em-cmpl em-basic em-banner em-alias
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esh-proc esh-arg esh-groups eshell esh-module esh-mode esh-util
elec-pair time-date tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/ns-win ns-win ucs-normalize mule-util
term/common-win tool-bar dnd fontset image regexp-opt fringe
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button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads kqueue cocoa ns multi-tty make-network-process emacs)
Memory information:
((conses 16 236075 13044)
(symbols 48 23407 1)
(miscs 40 55 96)
(strings 32 40652 1787)
(string-bytes 1 1228751)
(vectors 16 40619)
(vector-slots 8 799289 20336)
(floats 8 72 298)
(intervals 56 830 0)
(buffers 992 14))
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--- Begin Message ---
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Subject: |
Re: bug#40156: 26.3; append-to-file does not work on nonexistent file over ssh |
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Date: |
Sat, 21 Mar 2020 10:30:54 +0100 |
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User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) |
Version: 27.2
Sean Devlin <address@hidden> writes:
> Hi folks,
Hi Sean,
> I did a little digging, and I think the problem is in
> tramp-sh-handle-write-region around line 3240:
>
>> ;; If `append' is non-nil, we copy the file locally, and let
>> ;; the native `write-region' implementation do the job.
>> (when append (copy-file filename tmpfile 'ok))
>
> It looks like copy-file fails if filename doesn’t exist. Adding a test
> for file existence (i.e. file-exists-p) to the condition seems to
> solve the problem, though admittedly I only tested for my own narrow
> use case.
Thanks, and yes, your analysis is correct. I've committed a respective
patch to Emacs master. I've extended also tramp-tests.el
accordingly. The patch is appended.
Since Emacs 27.1 is already in pretest, I haven't applied it there. The
next Tramp release in GNU ELPA, 2.4.3.3, will contain the patch. It is
expected end of March.
> Thanks!
Best regards, Michael.
txtHW3JAorEyP.txt
Description: Text Data
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