Re: metastore (was: Track /etc directory using Git)

From: Daniel Barkalow <barkalow@iabervon.org>
Date: Sep 15, 2007, 19:56 UTC
Message-ID: <Pine.LNX.4.64.0709151430040.5298@iabervon.org>
In-Reply-To: <20070915145437.GA12875@piper.oerlikon.madduck.net>

On Sat, 15 Sep 2007, martin f krafft wrote:

Show 18 quoted lines

> also sprach Johannes Schindelin <Johannes.Schindelin@gmx.de> [2007.09.15.1610 +0200]:
> > No.  Git is a source code management system.  Everything else that
> > you can do with it is a bonus, a second class citizen.  Should we
> > really try to support your use case, we will invariably affect the
> > primary use case.
> 
> I thought git was primarily a content tracker... so it all comes
> down to how to define content, doesn't it? But either way, we need
> not discuss that because that definition depends a lot on context
> and purpose and thus cannot be answered once and for all.
> 
> I understand that for the primary use case, tracking nothing more
> than +x makes sense and should not be interfered with. This is why
> I was proposing a policy-based approach. The primary use case is
> unaffected, it's the default policy. Someone may choose to track
> other mode bits or file/inode attributes, according to one of
> several policies available with git, or even a custom policy. In
> that case, the repository needs to be appropriately configured.

Configuration options only apply to the local aspects of the repository. That is, when you clone a repository, you don't get the configuration options from it, in general. And changing configuration options on a repository does not have any effect on the content it contains. So configuration options aren't appropriate.

Show 7 quoted lines

> The reason why I say this should be done inside git rather than with
> hooks and an external tool, such as metastore is quite simple: git
> knows about every content entity in any tree of a repo and already
> has a data node for each object. Rather than introducing a parallel
> object database (shadow hierarchy or single file), it would make
> a lot more sense and be way more robust to attach additional
> information to these object nodes, wouldn't it?

Git doesn't have any way to represent owners or groups, and they would need to be represented carefully in order to make sense across multiple computers. If you're adding support for metadata-as-content (for more than "is this a script?"), you should be able to cover all of the common cases of extended stuff, like AFS-style ACLs. And if you want to allow meaningful development with this mechanism (as opposed to just archival of a sequence of states of a live system), the normal case will be that the metadata beyond +x is manipulated by ordinary users in some way other than modifying their working directory. So the normal case here will be like working on a filesystem that doesn't support symlinks or an executable bit when this is important content.

	-Daniel
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