Re: [RFC 1/5] GSOC: prepare svndump for branch detection

From: Florian Achleitner <florian.achleitner.2.6.31@gmail.com>
Date: Aug 20, 2012, 13:35 UTC
Message-ID: <1701463.olu8UUX9CV@flomedio>
In-Reply-To: <7v7gsum4oc.fsf@alter.siamese.dyndns.org>

On Sunday 19 August 2012 23:57:23 Junio C Hamano wrote:

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> Florian Achleitner <florian.achleitner.2.6.31@gmail.com> writes:
> >> This change makes me uncomfortable.
> >> We are doubling up on hashing with fast-import.
> >> This introduces git-specific logic into vcs-svn.
> 
> IIUC, vcs-svn/fast-export is meant to produce a stream in the
> fast-import format, and that format is meant to be VCS agnostic,
> it would need a careful thinking to add anything Git specific to
> it.  If you make other people's importers unable to read from you
> because you tell them the contents of blob in Git's terms, that is
> not very good.

Good point.

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> 
> > You have two choices of referencing that blobs later, by using a mark, or
> > by giving their sha1. Marks are already used for marking commits, and
> > there is only one "mark namespace". So I couldn't use marks to reference
> > the blobs in a nice way. This allows for referencing them by their sha1.
> 
> Surely you can, by using even and odd numbers (or modulo 4 if you
> may later want to mark trees and tags as well, but I doubt that is
> needed), no?

Currently, the mark number is equal to the svn revision number the commit corresponds to. I didn't want to break that, but not mandatory. We could also split the mark namespace by reserving one or more of the most significant bits as a type specifier. I'll develop a marks-based version ..