bug#20242: 24.5; compilation-mode and tramp interaction bug

[David Hull]

I believe that there is a bug in the interaction between
compilation-mode and tramp.  This bug exists in 24.5rc1, but also exists
in the previous emacs version, 24.4.1.  This is the situation:

I am running emacs on a Mac.  On the Mac, "/var" is a symlink to
"private/var".

I am using tramp to visit a project on a CentOS 6 VM.  The project on
the VM is in "/var/home/david.hull/src/ds-advertiser-server/src".

I run "M-x compile", and run "make -k" as the compilation command.
Compile creates a "*compilation*" buffer with the error messages.  Here
are the partial contents, prefixed with ">":

> -*- mode: compilation; default-directory: 
> "/scp:cos6:/var/home/david.hull/src/ds-advertiser-server/src/" -*-
> Compilation started at Wed Apr  1 10:18:47
> 
> ds_adv_ox3_ad_v5.erl:44: syntax error before: '}'

When I press Enter on this error line to run compile-goto-error, I get
the following message in the minibuffer:

Find this error in (default ds_adv_ox3_ad_v5.erl): 
/scp:cos6:/private/var/home/david.hull/src/ds-advertiser-server/src

Note that the file path begins with "/private/var" instead of "/var".  I
believe that either compilation-mode or tramp is attempting to expand
the symlinks, but is incorrectly expanding "/var" to "/private/var",
which would be correct on the Mac but is incorrect on the CentOS VM.

If I edit the path to remove "/private" then emacs is able to
successfully open the source file and position the cursor at the line
with the error.

Thanks.

-- 
David Hull





In GNU Emacs 24.5.1 (x86_64-apple-darwin13.4.0, NS apple-appkit-1265.21)
 of 2015-03-27 on builder10-9.porkrind.org
Windowing system distributor `Apple', version 10.3.1344
Configured using:
 `configure --with-ns '--enable-locallisppath=/Library/Application
 Support/Emacs/${version}/site-lisp:/Library/Application
 Support/Emacs/site-lisp''

Important settings:
  locale-coding-system: utf-8-unix

Major mode: Erlang

Minor modes in effect:
  magit-auto-revert-mode: t
  shell-dirtrack-mode: t
  diff-auto-refine-mode: t
  show-paren-mode: t
  icomplete-mode: t
  dtrt-indent-mode: t
  which-function-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Mark set
Saving file 
/scp:cos6:/var/home/david.hull/src/ds-advertiser-server/src/ds_adv_ox3_ad_v5.erl...
Copying /var/folders/y9/k3f9vqgn73gf64x8ktywlkd10r0222/T/tramp.24678j1V.erl to 
/scp:cos6:/var/home/david.hull/src/ds-advertiser-server/src/ds_adv_ox3_ad_v5.erl...
Tramp: Waiting for prompts from remote shell...
Tramp: Process has finished.
Tramp: Waiting for prompts from remote shell...done
Copying /var/folders/y9/k3f9vqgn73gf64x8ktywlkd10r0222/T/tramp.24678j1V.erl to 
/scp:cos6:/var/home/david.hull/src/ds-advertiser-server/src/ds_adv_ox3_ad_v5.erl...done
Wrote 
/scp:cos6:/var/home/david.hull/src/ds-advertiser-server/src/ds_adv_ox3_ad_v5.erl
Quit [2 times]
Making completion list...

Load-path shadows:
/Users/david.hull/.emacs.d/elpa/tabulated-list-20120406.1351/tabulated-list 
hides 
/Users/david.hull/Applications/Emacs-25.1rc1.app/Contents/Resources/lisp/emacs-lisp/tabulated-list

Features:
(shadow sort mail-extr emacsbug sendmail debug misearch multi-isearch
vc-git tempo etags erlang tramp-sh tramp-cache mule-util magit-key-mode
magit view tramp cl-macs cl gv tramp-compat auth-source gnus-util
password-cache tramp-loaddefs trampver shell pcomplete help-mode grep
compile comint epa derived epg diff-mode autorevert filenotify
ansi-color git-rebase-mode thingatpt git-commit-mode server log-edit
message format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode
mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mailabbrev mail-utils gmm-utils mailheader ring pcvs-util add-log paren
eieio byte-opt bytecomp byte-compile cl-extra cl-loaddefs cl-lib cconv
eieio-core info easymenu protobuf-mode-autoloads thrift-autoloads
unbound-autoloads icomplete dtrt-indent advice help-fns easy-mmode
which-func imenu package epg-config time-date tooltip electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel ns-win tool-bar dnd fontset
image regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode
register page menu-bar rfn-eshadow timer select scroll-bar mouse
jit-lock font-lock syntax facemenu font-core frame cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
cocoa ns multi-tty emacs)

Memory information:
((conses 16 204500 21401)
 (symbols 48 28308 0)
 (miscs 40 269 466)
 (strings 32 50267 4851)
 (string-bytes 1 1423905)
 (vectors 16 24983)
 (vector-slots 8 732657 8353)
 (floats 8 1299 66)
 (intervals 56 3140 281)
 (buffers 960 25))