Re: git transition issues

["Eric S. Raymond" <esr@thyrsus.com>]

David Caldwell <david@porkrind.org>:
> On 10/26/14 5:07 PM, esr@thyrsus.com (Eric S. Raymond) wrote:
> 
> > lisp/version.el: The bzr-specific code for version extraction will be
> > obsolete.  The git-specific code is very broken.  Among other
> > problems, in my stock Ubuntu environment the git log command it
> > generates always fails, apparently because it can't find terminal
> > capabilities it wants.
> 
> From version.el:
> 			  (call-process "git" nil '(t nil) nil "log"
> 					"-1" "--pretty=format:%N")
> 
> This looks wrong to me. %N is the commit's note from "git notes".
> Perhaps this should be %H, to get the commit hash? And if so, I think
> the better way is with "git show-ref", as it's a plumbing command where
> "git log" is not (git log likes to redirect stuff through your $PAGER, etc).
> 
>   git show-ref -s --head ^HEAD

I noticed the %N issue, yes.  I agree with this critique.

Consider this change, part of my transition-day patch:

+# Ideally, VCSWITNESS should be a file that is modified whenever the
+# repository registers a commit from either a local checkin or a
+# repository pull. In git there is no single file that guarantees
+# this, but the local log for the current head should be close enough.
+#
 # Note the use of single quotes in the value of vcswitness.
 # This passes an unexpanded $srcdir to src's Makefile, which then
 # expands it using its own value of srcdir (which points to the
 # source directory of src/).
 src: Makefile
-	dirstate='.bzr/checkout/dirstate';				\
+	dirstate='.git/logs/HEAD';				\
 	vcswitness='$$(srcdir)/../'$$dirstate;				\
 	[ -r "$(srcdir)/$$dirstate" ] || vcswitness='';			\
 	$(MAKE) -C $@ all VCSWITNESS="$$vcswitness"

Can you think of a better witness value?
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>