bug#13730: 24.3.50; Diff from Bzr-Log-View not highlighted

bug#13730: 24.3.50; Diff from Bzr-Log-View not highlighted

[rcopley]

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Visit a bzr branch, view the root log with "C-x v L", choose a revision
and invoke log-view-diff by typing "d". The diff that is shown should be
highlighted, but it isn't.
The trunk revision in which this stopped working is in (111784,11794].




In GNU Emacs 24.3.50.1 (i386-mingw-nt6.2.9200)
 of 2013-02-16 on MACHINE
Bzr revision: 111803 kjambunathan@gmail.com-20130216092642-8iu1ekcuhdzzp8ea
Windowing system distributor `Microsoft Corp.', version 6.2.9200
Configured using:
 `configure --with-gcc (4.7) --cflags -I c:/gnuwin32/include --ldflags
 -L c:/gnuwin32/lib'


Important settings:
  value of $LANG: ENG
  locale-coding-system: cp1252
  default enable-multibyte-characters: t


Major mode: Diff


Minor modes in effect:
  whitespace-mode: t
  diff-auto-refine-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t


Recent input:
C-x v L d M-x r e p o r t - e m a c s - b u g <ret
urn>


Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Finding changes in g:/emacs/trunk/...


Load-path shadows:
None found.


Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils whitespace diff-mode add-log log-view easymenu
easy-mmode pcvs-util vc-bzr vc-sccs vc-svn vc-cvs vc-rcs vc
vc-dispatcher dired time-date tooltip ediff-hook vc-hooks
lisp-float-type mwheel dos-w32 ls-lisp w32-common-fns disp-table w32-win
w32-vars tool-bar dnd fontset image regexp-opt fringe tabulated-list
newcomment lisp-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 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 w32notify w32
multi-tty emacs)

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bug#13730: 24.3.50; Diff from Bzr-Log-View not highlighted

[Glenn Morris]

> Visit a bzr branch, view the root log with "C-x v L", choose a revision
> and invoke log-view-diff by typing "d". The diff that is shown should be
> highlighted, but it isn't.

Do you mean that font-locking should be enabled in the *vc-diff* buffer?
If so, it is for me. (Try bootstrapping?)

Or did you mean that the corresponding line in the *vc-change-log*
buffer should be highlighted in some way?

Or something else?

> The trunk revision in which this stopped working is in (111784,11794].

bug#13730: 24.3.50; Diff from Bzr-Log-View not highlighted

[Richard Copley]

On 17 February 2013 01:16, Glenn Morris <rgm@gnu.org> wrote:
>
>> Visit a bzr branch, view the root log with "C-x v L", choose a revision
>> and invoke log-view-diff by typing "d". The diff that is shown should be
>> highlighted, but it isn't.
>
> Do you mean that font-locking should be enabled in the *vc-diff* buffer?
> If so, it is for me. (Try bootstrapping?)

That is what I mean, yes. Curious. Did you follow the recipe from
"emacs -Q"? Not all *vc-diff* buffers are affected.

>> The trunk revision in which this stopped working is in (111784,11794].

Make that (111793,111794]. Revision 111794 introduces a new feature in
"easy-mmode.el" that allows major mode functions to disable global
minor modes by explicitly turning off the corresponding minor mode.
Unfortunately font-lock gets turned off in a change-major-mode-hook
function (font-lock-change-mode in "font-core.el"), which doesn't seem
to have been anticipated.

I can't say I understand why this doesn't cause global-font-lock-mode
to be disabled in all major modes in all circumstances. It could be a
question of whether font-lock-change-mode or
global-font-lock-mode-enable-in-buffers is earlier in
change-major-mode-hook.

bug#13730: 24.3.50; Diff from Bzr-Log-View not highlighted

[Richard Copley]

> Unfortunately font-lock gets turned off in a change-major-mode-hook
> function (font-lock-change-mode in "font-core.el"), which doesn't seem
> to have been anticipated.

Sorry, that's a red herring, it has nothing to do with font-lock-change-mode.

Now that turning a minor mode off during a major mode function
disables the corresponding global minor mode, turning the minor mode
back on should re-enable the global minor mode, as in the patch below.

(In Emacs trunk, whitespace mode is turned on in diff mode by a
directory-local variable. Thus the function `whitepace-turn-on' is
called from inside the diff-mode major mode function; but
`whitespace-turn-on' turns font lock off and turns it back on again.)

=== modified file 'lisp/emacs-lisp/easy-mmode.el'
*** lisp/emacs-lisp/easy-mmode.el	2013-02-15 20:01:51 +0000
--- lisp/emacs-lisp/easy-mmode.el	2013-02-17 05:18:06 +0000
***************
*** 461,468 ****
         ;; kill-all-local-variables.
         (defvar-local ,disable-MODE nil)
         (defun ,MODE-disable-in-buffer ()
! 	 (unless ,mode
! 	   (setq ,disable-MODE t)))
         (put ',MODE-disable-in-buffer 'definition-name ',global-mode))))

  ;;;
--- 461,467 ----
         ;; kill-all-local-variables.
         (defvar-local ,disable-MODE nil)
         (defun ,MODE-disable-in-buffer ()
!          (setq ,disable-MODE (not ,mode)))
         (put ',MODE-disable-in-buffer 'definition-name ',global-mode))))

  ;;;

bug#13730: 24.3.50; Diff from Bzr-Log-View not highlighted

[Glenn Morris]

Please keep the debbugs address cc'd.

Richard Copley wrote (on Sun, 17 Feb 2013 at 03:35 +0000):

> > Do you mean that font-locking should be enabled in the *vc-diff* buffer?
> > If so, it is for me. (Try bootstrapping?)
> 
> That is what I mean, yes. Curious. Did you follow the recipe from
> "emacs -Q"? Not all *vc-diff* buffers are affected.

Yes. Works for me.

> >> The trunk revision in which this stopped working is in (111784,11794].
> 
> Make that (111793,111794]. Revision 111794 introduces a new feature
> in "easy-mmode.el" that allows major mode functions to disable
> global minor modes by explicitly turning off the corresponding minor
> mode. Unfortunately font-lock gets turned off in a
> change-major-mode-hook function (font-lock-change-mode in
> "font-core.el"), which doesn't seem to have been anticipated.
> 
> I can't say I understand why this doesn't cause
> global-font-lock-mode to be disabled in all major modes in all
> circumstances. It could be a question of whether
> font-lock-change-mode or global-font-lock-mode-enable-in-buffers is
> earlier in change-major-mode-hook.

bug#13730: 24.3.50; Diff from Bzr-Log-View not highlighted

[Glenn Morris]

Richard Copley wrote:

> (In Emacs trunk, whitespace mode is turned on in diff mode by a
> directory-local variable.

Oh, that's the difference. I've removed that locally because I don't see
what business that is of Emacs's dir-locals file.

bug#13730: 24.3.50; Diff from Bzr-Log-View not highlighted

[Richard Copley]

Richard Copley wrote:
>> Now that turning a minor mode off during a major mode function
>> disables the corresponding global minor mode, turning the minor mode
>> back on should re-enable the global minor mode, as in the patch below.

On reflection it seems to me the new code in 111794 was explicitly
intended not to do what I suggested in my patch, so the author of it
will no doubt have other ideas.

Glenn Morris wrote:
>Richard Copley wrote:
>> (In Emacs trunk, whitespace mode is turned on in diff mode by a
>> directory-local variable.
>
> Oh, that's the difference. I've removed that locally because I don't see
> what business that is of Emacs's dir-locals file.

If it's not a silly question, how exactly do you do that? I clean,
revert and pull before I bootstrap (quiet at the back). Is it just a
matter of omitting the revert?

bug#13730: 24.3.50; Diff from Bzr-Log-View not highlighted

[Glenn Morris]

Richard Copley wrote:

>> Oh, that's the difference. I've removed that locally because I don't see
>> what business that is of Emacs's dir-locals file.
>
> If it's not a silly question, how exactly do you do that? I clean,
> revert and pull before I bootstrap (quiet at the back). Is it just a
> matter of omitting the revert?

I just leave dir-locals.el locally modified. (Sorry for confusing the
issue with this, BTW. I do also keep a pristing branch around for
checking things, normally.)