From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?iso-8859-1?Q?Bj=F6rn?= Steinbrink <B.Steinbrink@gmx.de>
Subject: Re: why is git destructive by default? (i suggest it not be!)
Date: Tue, 24 Jun 2008 10:35:17 +0200
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Cc: Jakub Narebski <jnareb@gmail.com>,
	Avery Pennarun <apenwarr@gmail.com>,
	Nicolas Pitre <nico@cam.org>, git@vger.kernel.org
To: David Jeske <jeske@google.com>
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On 2008.06.24 08:08:13 -0000, David Jeske wrote:
> To re-ask the same question I asked in my last post, using your ascii
> pictures...
>=20
>=20
> Let's assume we're here..
>=20
> .<---.<---.<---A<---X<---Y    <--- master
> \
> \--B<---C    <--- customer_A_branch <=3D=3D=3D HEAD
>=20
>=20
> And this person and everyone else moves their head pointers back to m=
aster
> without merging:
>=20
>=20
> .<---.<---.<---A<---X<---Y    <--- master              <=3D=3D=3D HEA=
D
> \
> \--B<---C    <--- customer_A_branch
>=20
>=20
> Now, five years down the road, our tree looks like:
>=20
>=20
> .<---A<---X<---Y<---.<--.<--.(3 years of changes)<---ZZZ<--- master  =
<=3D=3D=3D HEAD
> \
> \--B<---C   <--- customer_A_branch
>=20
> And someone does:
>=20
> git-branch -f customer_A_branch ZZZ
>=20
> To bring us to:
>=20
> .<---A<---X<---Y<---.<--.(3 years of changes)<---ZZZ<--- master  <=3D=
=3D=3D HEAD
> \                                           \
> \--B<---C                                   \-- customer_A_branch
>=20
>=20
> ..at this point, will a GC keep "B<--C", or garbage collect the commi=
ts and
> throw them away?

That would throw away the changes in _that_ repository after the reflog
entry has expired. It would not affect any other repo yet, and if that
developer tries to push that new customer_A_branch, it would be refused=
,
because it is not a fast-forward. And if the repo he's trying to push t=
o
simply doesn't allow any non-fast-forward pushes, then even push -f
won't help him to destroy anything.

Bj=F6rn