Re: [PATCH v2 4/5] Makefile: use the sha1collisiondetection submodule by default

[Jeff King <peff@peff.net>]

On Fri, Dec 08, 2017 at 03:21:23PM -0800, Junio C Hamano wrote:

> Junio C Hamano <gitster@pobox.com> writes:
> 
> > That endgame allows us not force people to grab an essential part of
> > the codebase as an external dependency from another place, which
> > feels quite bad, especially when their primary interest is not in
> > dogfooding submodule but in building a working version of Git.
> >
> > Removing one and keeping the other between the two will make the
> > distribution more streamlined by removing the build-time knob we
> > need to tweak, but the one that gets removed does not have to be the
> > in-tree one that allows people to "git clone" from just one place.
> 
> Perhaps this may deserve a bit more explanation.
> 
> I wouldn't be so against "let's do submodule-only" if this were not
> SHA-1 implementation but something like gitk and git-gui.  An optional
> part of a system that it is safe to leave to individual builders if
> they want to fetch and use that part *is* an ideal target to bind as
> a submodule to the system.
> 
> It's just the "default SHA-1 implementation" is at the far opposite
> end of the spectrum from "an optional part", and our use of
> submodule to bind this code is definitely *not* because it makes
> sense to use submodule in that context; it is because developers
> (not necessarily those who consume Git sourcecode) *wanted* to use
> submodule there, regardless of the real merit of doing so.

Thanks for writing this out. I had a vague feeling that I didn't quite
like going the submodule-only direction, but I was having trouble
putting into words. It's exactly this.

-Peff