bug#1741: 23.0.60; vc fail to register file while logged as /su:: with tramp

[Dan Nicolaescu <dann@ics.uci.edu>]

thierry.volpiatto@gmail.com writes:

  > Hi Dan!
  > Thank you to have a look at this bug.
  > It's a long time, i didn't remember i sent this bug.
  > The bug is still here.(23.0.92)
  > 
  > Dan Nicolaescu <dann@ics.uci.edu> writes:
  > 
  > > Thierry Volpiatto <thierry.volpiatto@gmail.com> writes:
  > >
  > >   > Please write in English if possible, because the Emacs maintainers
  > >   > usually do not have translators to read other languages for them.
  > >   > 
  > >   > Your bug report will be posted to the emacs-pretest-bug@gnu.org mailing list.
  > >   > 
  > >   > Please describe exactly what actions triggered the bug
  > >   > and the precise symptoms of the bug:
  > >   > 
  > >   > Hi, 
  > >   > i can't register a file with vc/rcs when i am logged as root throught
  > >   > tramp.
  > >   > 1) C-x v i
  > >   > 2) Create RCS dir (y/n) ==> The dir is created.
  > >   > 3) But now ==> _Here the debug output_:
  > >   > 
  > >   > ,----
  > >   > | Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  > >   > |   file-exists-p(nil)
  > >   > |   vc-insert-file(nil "^[0-9]")
  > >   > |   vc-rcs-fetch-master-state("/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   vc-rcs-working-revision("/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   apply(vc-rcs-working-revision "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   vc-call-backend(RCS working-revision "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   vc-working-revision("/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   vc-default-mode-line-string(RCS "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   apply(vc-default-mode-line-string RCS "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   vc-call-backend(RCS mode-line-string "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   vc-mode-line("/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   run-hook-with-args(vc-mode-line "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > >   > |   vc-resynch-window("/su:root@tux.homenetwork:/usr/local/bin/editeur.sh" t t)
  > >   > |   vc-resynch-buffer("/su:root@tux.homenetwork:/usr/local/bin/editeur.sh" t t)
  > >   > | 
  > >   > | [...]
  > >   > | 
  > >   > | [G70600 G70601 rev comment file --cl-dolist-temp-- 
  > >   > | message "Registering %s... " mapc vc-file-clearprops vc-call-backend
  > >   > |   register nil vc-file-setprop 
  > >   > | vc-backend "Registering %s... done"] 6] (quote --files--) (quote --backend--) --cl-rest--)))
  > >   > |   vc-register(nil)
  > >   > |   call-interactively(vc-register nil nil)
  > >   > `----
  > >   > 
  > >   > _And if i want to delete RCS directory from dired_:
  > >   > 
  > >   > ,----
  > >   > | (file-error Couldn't delete /su:root@tux.homenetwork:/usr/local/bin/RCS)
  > >   > `----
  > >   > 
  > >   > However if i open an emacs  root session i can register my file as
  > >   > normal.
  > >
  > > What happens is that vc-check-master-templates gets called with
  > > "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh", and it calls 
  > > (file-exists-p "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > > which returns nil.
  > No, `file-exists-p' recognize tramp file name and return t.
  > 
  > (file-exists-p "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")
  > ==>t

It's a bug in TRAMP: 

If I create a new file: "/su:root@localhost:/tmp/blah"
then to C-x v v to register it, it fails.  But I can see that the 
/tmp/RCS/blah,v is created.  If after that I do:

M-: (file-exists-p "/su:root@localhost:/tmp/RCS/blah,v") RET
the result is nil.

If I start a new emacs and do:
M-: (file-exists-p "/su:root@localhost:/tmp/RCS/blah,v") RET
the result is t.




  > The problem is, i think, vc call `file-exists-p' with (vc-name fname) as
  > argument instead of "file_name":
  > 
  > ,----[ With a tramp filename return error ]
  > | (file-exists-p (vc-name "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh"))
  > | ==>
  > | Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  > |   file-exists-p(nil)
  > |   eval((file-exists-p (vc-name "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")))
  > |   eval-expression((file-exists-p (vc-name "/su:root@tux.homenetwork:/usr/local/bin/editeur.sh")) nil)
  > |   call-interactively(eval-expression nil nil)
  > `----
  > 
  > ,----[ With a regular filename return t ]
  > | (file-exists-p (vc-name "~/bin/call-gnus.sh"))
  > | ==>t
  > `----
  > 
  > So it seem the problem come from vc that try to set properties on
  > filename with `vc-name' and fail on tramp filename.
  > (`vc-name' call `vc-file-getprop')
  > 
  > Thought i didn't look at the code carefully, so i am may be wrong.
  > 
  > 
  > > There's a few other `file-exists-p' calls in vc*.el, so it's likely that
  > > other things can go wrong if this one instance is somehow fixed.
  > >
  > > If someone familiar with what tramp needs wants to get this to work,
  > > about all vc calls need to be tested to make sure they don't do
  > > something that tramp can't do.
  > >
  > 
  > -- 
  > A + Thierry Volpiatto
  > Location: Saint-Cyr-Sur-Mer - France