Re: Output from "git blame A..B -- path" for the bottom commit is misleading

[John Keeping <john@keeping.me.uk>]

On Thu, May 08, 2014 at 02:58:58PM -0700, Junio C Hamano wrote:
> John Keeping <john@keeping.me.uk> writes:
> 
> > On a slight tangent, I tried this in a fairly young repository and got
> > this (with master at v2.0.0-rc2-4-g1dc51c6):
> >
> > $ git blame Makefile | head -5
> > 7a3fc144 (John Keeping      2013-12-26 17:37:53 +0000   1) REL_VERSION = v0.2
> > 5c9829f9 (John Keeping      2013-07-29 17:03:26 +0100   2) 
> > 5c9829f9 (John Keeping      2013-07-29 17:03:26 +0100   3) # The default target is...
> > ^f7fae99 (John Keeping      2013-03-24 17:14:40 +0000   4) all::
> > ^f7fae99 (John Keeping      2013-03-24 17:14:40 +0000   5) 
> >
> > f7fae99 is the initial commit in the repository, so shouldn't the last
> > two lines blame to that, not a non-existent ancestor?
> 
> It is not saying f7fae99^, is it?  It is debatable if it is correct
> to mark the root commit as a boundary, but that is what it is
> showing, I think.  In other words, "this line hasn't changed since
> the inception of the project".

Yes, it's marking it as a boundary but I'm not convinced that's correct.
Compare these two cases:

$ git blame Makefile | head -5
7a3fc144 (John Keeping      2013-12-26 17:37:53 +0000   1) REL_VERSION = v0.2
5c9829f9 (John Keeping      2013-07-29 17:03:26 +0100   2) 
5c9829f9 (John Keeping      2013-07-29 17:03:26 +0100   3) # The default target is...
^f7fae99 (John Keeping      2013-03-24 17:14:40 +0000   4) all::
^f7fae99 (John Keeping      2013-03-24 17:14:40 +0000   5) 

$ git blame ^5c9829f9 Makefile | head -5
7a3fc144 (John Keeping      2013-12-26 17:37:53 +0000   1) REL_VERSION = v0.2
^5c9829f (John Keeping      2013-07-29 17:03:26 +0100   2) 
^5c9829f (John Keeping      2013-07-29 17:03:26 +0100   3) # The default target is...
^5c9829f (John Keeping      2013-07-29 17:03:26 +0100   4) all::
^5c9829f (John Keeping      2013-07-29 17:03:26 +0100   5) 


While it might be useful to mark the initial commit, the current output
seems to mean that lines 4 and 5 existed before the repository was
created.  If you consider blame's output to mean "introduced by commit"
then those lines should simply blame to the initial commit.

`git log --boundary` does not mark the initial commit as a boundary.