bug#5291: 23.1.91; "bzr status" FAILED

[Eli Zaretskii]

> Date: Sun, 03 Jan 2010 06:09:58 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 5291@debbugs.gnu.org
> 
> > Date: Sat, 2 Jan 2010 14:17:30 -0800 (PST)
> > From: Dan Nicolaescu <dann@ics.uci.edu>
> > Cc: 5291@debbugs.gnu.org
> > 
> > What exactly creates the d:/gnu/bzr/emacs/trunk/bzr_log.ahvp69 file?
> 
> "bzr commit" does.  This file is where it puts the list of files to be
> committed, then submits it to $EDITOR (in my case, emacsclient), and
> expects me to insert the commit message there.  After "bzr commit" is
> done (i.e., the changes committed), this file is deleted by bzr.
> 
> > Is your TEMP set to d:/gnu/bzr/emacs/trunk/ ?
> 
> No.  AFAIU, bzr creates these temporary files in the directory where
> you run "bzr commit".  I see these files created in the current
> directory on GNU/Linux as well, although I will have to check if the
> same problem happens there as well as on Windows.
> 
> > I think that if you change:
> >                    (vc-bzr-command "status" t 0 file)
> > to:
> >                    (vc-bzr-command "status" t 3 file)
> > in vc-bzr-status
> > it should work, but I am not 100% sure that's TRTD.
> 
> OK, I will look into this when I have a chance.  Thanks.

I found the problem.  It seems to be Windows-specific.  (I cannot
reproduce it on GNU/Linux, but I have a slightly different version of
Bazaar there, so it could be bzr-version specific as well.  Still, the
nature of the problem (see below) makes it a safe bet that it exists
only on Windows.)

The detailed reason for the failure is found in the .bzr.log file:

  LockContention: Could not acquire lock 
"D:/gnu/bzr/emacs/test/.bzr/checkout/dirstate": (32, 'CreateFileW', 'The 
process cannot access the file because it is being used by another process.')

What happens is evidently this:

  . I run "bzr ci", which locks dirstate and launches emacsclient to
    edit the commit message that it puts on a temporary file
    bzr_log.FOO in the directory where I run "bzr ci".

  . The file with the commit message pops up in Emacs, where I edit it.

  . When I'm done editing, I save the bzr_log.FOO file.

  . Emacs then run "bzr status bzr_log.FOO" as a side effect of C-x
    C-s, because the file is inside a versioned directory.  This "bzr
    status" tries to lock dirstate again, which fails, because Windows
    fails the CreateFileW system call due to sharing issues.

I could probably submit a bug for Bazaar, but they would probably say
that Emacs is to blame as well as Bazaar: it is Emacs who invokes the
second instance of bzr while the first is still running.

It would be nice if I could tell Bazaar to put those bzr_log.FOO files
under $TMPDIR, but there doesn't seem to be a way of doing that.
Anyone?

Any ideas for how best to resolve this?

> Do you (or someone else) know where can I find the documentation of
> status code returned by bzr?

To answer my own question: exit status 3 means that there was some
fatal exception or error in running the command.  When that happens,
bzr writes a full traceback to .bzr.log file, so one should look there
for that info.