Gentoo Archives: gentoo-dev

From: "Michał Górny" <mgorny@g.o>
To: gentoo-dev@l.g.o
Cc: kentfredric@×××××.com
Subject: Re: [gentoo-dev] Re: Portage Git migration - clean cut or git-cvsserver
Date: Fri, 01 Jun 2012 11:44:37
Message-Id: 20120601134439.049aa294@pomiocik.lan
In Reply to: Re: [gentoo-dev] Re: Portage Git migration - clean cut or git-cvsserver by Kent Fredric
1 On Fri, 1 Jun 2012 23:23:34 +1200
2 Kent Fredric <kentfredric@×××××.com> wrote:
3
4 > On 1 June 2012 22:54, Rich Freeman <rich0@g.o> wrote:
5 > > Rebasing re-applies the same diff to the new head to give you a new
6 > > set of commits.  When you apply the same diff to a different parent
7 > > you end up with a different tree, so the tree signature won't be the
8 > > same either.
9 >
10 > Not nessecarily. Given that :
11 >
12 > a file with a given content has a fixed SHA
13 > A tree is just a list of these SHA's , and that in turn is referenced
14 > by SHA, so if 2 commits have identical file content, their 'tree' sha
15 > will be the same ( in theory ).
16 >
17 > So that means, if you perform a rebase, assuming the filesystem looks
18 > the same as it did before the rebase, it will have the same SHA1 for
19 > the tree, regardless of the process of how it got to be that way.
20
21 I don't think that 'not necessarily' makes any difference here. Maybe
22 in our particular case this is not as likely as with regular source
23 code tree but while rebasing you can hit conflicts. And then files
24 start to change...
25
26 --
27 Best regards,
28 Michał Górny

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