[PATCH] Fix for vc-bzr-diff when vc-bzr-diff-switches is t

[Deniz Dogan]

I have had problems with vc-bzr-diff for some time now, getting errors
about some file not being found.  After much digging around in the VC
architecture, I realized that the problem is of course that I don't
have the diff tool installed, as I'm on Windows 7 without cygwin.

But since "bzr diff" works for me in a command prompt, I figured doing
a bzr diff in Emacs should work too, as long as it doesn't pass
--diff-options to bzr, which would require the diff tool.

So I set vc-bzr-diff-switches to t which means that I don't want to
pass any options to diff.  However, Emacs still executes:

bzr diff --diff-options  the-file

This breaks bzr completely as bzr expects diff options after
--diff-options.  So I wrote the attached patch for vc-bzr.el which
takes care of the case when vc-bzr-diff-switches is t, i.e., when we
don't want any diff switches, resulting in:

bzr diff the-file

I'm not ready to say that the attached patch is good to go, as I'm
pretty new to the VC package in general, so I'd appreciate it if you
guys test it out.

Thanks

--
Deniz Dogan



# Bazaar merge directive format 2 (Bazaar 0.90)
# revision_id: address@hidden
#   34dve8s23jpoym3a
# target_branch: bzr+ssh://address@hidden/emacs/trunk/
# testament_sha1: ba35bbaf78d6175412e7b8afee93cc1452de2fc1
# timestamp: 2011-01-26 14:42:36 +0100
# base_revision_id: address@hidden
#
# Begin patch
=== modified file 'lisp/ChangeLog'
--- lisp/ChangeLog      2011-01-25 17:41:28 +0000
+++ lisp/ChangeLog      2011-01-26 13:40:56 +0000
@@ -1,3 +1,8 @@
+2011-01-26  Deniz Dogan  <address@hidden>
+
+       * vc/vc-bzr.el (vc-bzr-diff): Don't pass --diff-options if
+       vc-bzr-diff-switches is t.
+
 2011-01-25  Sam Steingold  <address@hidden>

        * vc/vc-svn.el (vc-svn-diff): Use `diff-command' instead of the

=== modified file 'lisp/vc/vc-bzr.el'
--- lisp/vc/vc-bzr.el   2011-01-25 04:08:28 +0000
+++ lisp/vc/vc-bzr.el   2011-01-26 13:40:56 +0000
@@ -674,18 +674,23 @@

 (defun vc-bzr-diff (files &optional rev1 rev2 buffer)
   "VC bzr backend for diff."
-  ;; `bzr diff' exits with code 1 if diff is non-empty.
-  (apply #'vc-bzr-command "diff" (or buffer "*vc-diff*")
-        (if vc-disable-async-diff 1 'async) files
-         "--diff-options" (mapconcat 'identity
-                                     (vc-switches 'bzr 'diff)
-                                    " ")
-         ;; This `when' is just an optimization because bzr-1.2 is *much*
-         ;; faster when the revision argument is not given.
-         (when (or rev1 rev2)
-           (list "-r" (format "%s..%s"
-                              (or rev1 "revno:-1")
-                              (or rev2 ""))))))
+  (let (args)
+    (unless (eq t vc-bzr-diff-switches) ;; t means "no switches"
+      (setq args
+            (list "--diff-options" (mapconcat 'identity
+                                              (vc-switches 'bzr 'diff)
+                                              " "))))
+    ;; This `when' is just an optimization because bzr-1.2 is *much*
+    ;; faster when the revision argument is not given.
+    (when (or rev1 rev2)
+      (setq args (append args (list "-r" (format "%s..%s"
+                                                 (or rev1 "revno:-1")
+                                                 (or rev2 ""))))))
+    ;; `bzr diff' exits with code 1 if diff is non-empty.
+    (apply #'vc-bzr-command "diff" (or buffer "*vc-diff*")
+           (if vc-disable-async-diff 1 'async) files
+           args)))
+


 ;; FIXME: vc-{next,previous}-revision need fixing in vc.el to deal with

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