bug#4451: 23.1; EOL problems with vc-diff and cygwin

[Reiner Steib <Reiner.Steib@gmx.de>]

On Thu, Jul 15 2010, Eli Zaretskii wrote:

>> From: Reiner Steib <reinersteib+gmane@imap.cc>
>> Cc: 4451@debbugs.gnu.org, Stefan Monnier <monnier@iro.umontreal.ca>
>> Date: Thu, 15 Jul 2010 09:22:39 +0200
>> 
>> > So I agree with Stefan that you should simply not overwrite the
>> > checked-out file with Unix EOLs.  We could install the change
>> > suggested by Stefan (based on this analysis, I no longer object to
>> > it), 
>> 
>> If nobody else objects, may I install[1] Stefan's patch?  Or we could
>> make it depend on some variable as well ...
>
> Fine with me.

Thanks.

>> +(defvar vc-coding-system-strip-eol t ;; nil
>> +  "When non-nil, don't inherit the EOL part of the coding-system.")
>
> Instead of a slightly misleading name (you don't really "strip" EOL)
> and double negation, I would suggest an option named
> vc-coding-system-inherit-eol, non-nil by default (to keep the current
> operation), and reverse the condition in the patch.

Heres an updated patch.  Could someone please apply it (I don't have
the current sources - no bzr checkout yet)?

--8<---------------cut here---------------start------------->8---
--- vc.el	7 Dec 2009 09:02:16 -0000	1.746
+++ vc.el	16 Jul 2010 06:47:30 -0000
@@ -1388,6 +1388,12 @@
 ;;          (vc-call-backend ',(vc-backend f)
 ;;                           'diff (list ',f) ',rev1 ',rev2))))))
 
+(defvar vc-coding-system-inherit-eol t
+  "When non-nil, inherit the EOL part of the coding-system from buffer.
+Set this variable to nil if your diff tools chooses to use other
+EOL type than the current buffer.  Then auto-detection gives
+better.") ;; Cf. bug#4451.
+
 (defun vc-coding-system-for-diff (file)
   "Return the coding system for reading diff output for FILE."
   (or coding-system-for-read
@@ -1395,7 +1401,12 @@
       ;; use the buffer's coding system
       (let ((buf (find-buffer-visiting file)))
         (when buf (with-current-buffer buf
-		    buffer-file-coding-system)))
+		    (if vc-coding-system-inherit-eol
+			buffer-file-coding-system
+		      ;; Don't inherit the EOL part of the coding-system,
+		      ;; because some diff tools may choose to use
+		      ;; another one.  bug#4451.
+		      (coding-system-base buffer-file-coding-system)))))
       ;; otherwise, try to find one based on the file name
       (car (find-operation-coding-system 'insert-file-contents file))
       ;; and a final fallback
--8<---------------cut here---------------end--------------->8---

Bye, Reiner.
-- 
       ,,,
      (o o)
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