GNU bug report logs - #1384
vc-diff-switches inconsistencies

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Francesco Potorti` <pot <at> gnu.org>
To: GNU emacs bug list <bug-gnu-emacs <at> gnu.org>
Subject: vc-diff for the hg backend ignore diff switches variables
Date: Tue, 23 Sep 2008 16:57:24 +0200

Three related problems:

1)
Apparently the hg backend of vc ignores both diff-switches and
vc-diff-switches.

2)
The vc-hg-diff-switches variables is not defined.

3)
The hg backend is special with respect to the vc-diff-switches
variable.  Its doc says:

  A string or list of strings specifying switches for diff under VC.
  When running diff under a given BACKEND, VC concatenates the values of
  `diff-switches', `vc-diff-switches', and `vc-BACKEND-diff-switches' to
  get the switches for that command.  Thus, `vc-diff-switches' should
  contain switches that are specific to version control, but not
  specific to any particular backend.

This behaviour assumes that the diff switches can be accumulated.
however, it does not allow for removing them for a particular backend.
For example, I have

(setq diff-switches "-pu"
      vc-diff-switches "-b")

which works for the cvs and rcs backends.  However, it would not work
for the hg backend, as 'hg diff' does not tolerate the -u option.  This
problem would require a different way of combining the diff switches.

Message #8 received at 1017 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: Francesco Potorti` <pot <at> gnu.org>
Cc: 1017 <at> debbugs.gnu.org
Subject: Re: bug#1017: vc-diff for the hg backend ignore diff switches variables
Date: Sat, 27 Sep 2008 21:59:24 -0400

Francesco Potorti` wrote:

> 1)
> Apparently the hg backend of vc ignores both diff-switches and
> vc-diff-switches.
>
> 2)
> The vc-hg-diff-switches variables is not defined.
>
> 3)
> The hg backend is special with respect to the vc-diff-switches
> variable.

I don't use hg, but try the included patch, based on vc-svn.

[vc-diff-switches]

>   A string or list of strings specifying switches for diff under VC.
>   When running diff under a given BACKEND, VC concatenates the values of
>   `diff-switches', `vc-diff-switches', and `vc-BACKEND-diff-switches' to
>   get the switches for that command.  Thus, `vc-diff-switches' should
>   contain switches that are specific to version control, but not
>   specific to any particular backend.

The above does not appear to be true.

The `vc-switches' command uses either vc-BACKEND-diff-switches, or
vc-diff-switches, or diff-switches. It does not append any of these.

Most vc-BACKEND-diff commands seem to use the above behaviour.

vc-cvs-diff appends diff-switches and vc-diff-switches, but only if it
does not have to call cvs to get a diff. If it does, it uses the
vc-switches method.

vc-mtn-diff and vc-git-diff don't use any switches.

It is all rather confusing...


*** vc-hg.el.~1.85.~	2008-07-05 12:09:45.000000000 -0700
--- vc-hg.el	2008-09-27 18:29:00.000000000 -0700
***************
*** 123,128 ****
--- 123,142 ----
    :version "22.2"
    :group 'vc)
  
+ (defcustom vc-hg-diff-switches
+   t                           ; Hg doesn't support common args like -u
+   "String or list of strings specifying extra switches for Hg diff under VC.
+ If nil, use the value of `vc-diff-switches'.
+ If you want to force an empty list of arguments, use t."
+   :type '(choice (const :tag "Unspecified" nil)
+ 		 (const :tag "None" t)
+ 		 (string :tag "Argument String")
+ 		 (repeat :tag "Argument List"
+ 			 :value ("")
+ 			 string))
+   :version "23.1"
+   :group 'vc)
+ 
  
  ;;; Properties of the backend
  
***************
*** 248,254 ****
  (defun vc-hg-diff (files &optional oldvers newvers buffer)
    "Get a difference report using hg between two revisions of FILES."
    (let* ((firstfile (car files))
! 	 (working (and firstfile (vc-working-revision firstfile))))
      (when (and (equal oldvers working) (not newvers))
        (setq oldvers nil))
      (when (and (not oldvers) newvers)
--- 262,270 ----
  (defun vc-hg-diff (files &optional oldvers newvers buffer)
    "Get a difference report using hg between two revisions of FILES."
    (let* ((firstfile (car files))
! 	 (working (and firstfile (vc-working-revision firstfile)))
! 	 (switches
!           (vc-switches (if vc-hg-diff-switches 'HG) 'diff)))
      (when (and (equal oldvers working) (not newvers))
        (setq oldvers nil))
      (when (and (not oldvers) newvers)
***************
*** 259,264 ****
--- 275,281 ----
  		       (expand-file-name default-directory))
  	   "diff"
  	   (append
+ 	    switches
  	    (when oldvers
  	      (if newvers
  		  (list "-r" oldvers "-r" newvers)

Message #13 received at 1017 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: 1017 <at> debbugs.gnu.org
Cc: Francesco Potorti` <pot <at> gnu.org>
Subject: Re: bug#1017: vc-diff for the hg backend ignore diff switches variables
Date: Sat, 04 Oct 2008 16:31:04 -0400

Since I do not use Mercurial, I need someone who does to check that
patch works.

Message #24 received at 1384-quiet <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: 1384-quiet <at> debbugs.gnu.org
Subject: Re: bug#1384
Date: Tue, 25 Nov 2008 22:04:03 -0500

I think the only remaining issues are:

i) vc-arch does not apply any diff switches (arch's diff does not seem
to accept many).

ii) vc-cvs uses the switches in different ways depending on whether it
needs to call cvs or not.

iii) many backends don't append the various diff switches, as
previously described in the behavior of vc-switches.

Message #29 received at 1384-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: 1384-done <at> debbugs.gnu.org
Subject: Re: Bug#1384
Date: Wed, 3 Dec 2008 02:59:34 -0500

I believe this is tidied up now.

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