Re: svn:externals using git submodules

[Andy Parkins <andyparkins@gmail.com>]

On Tuesday 2007, May 01, Chris Shoemaker wrote:

> > Actually that is an interesting point that Chris makes.  Isn't the
> > svn:externals property revision controlled on the parent directory?
> > So each change to it is actually recorded in the revision history
> > of the parent project.
>
> Yes and yes.

Yes and no.  Think of svn:externals as a file in the parent repository; 
it contains

 directory-name URL

Now, changes to that file _are_ tracked, in that if I changed the URL 
that change would be recorded in the parent repository.  However, 
nowhere is the revision of the external recorded.  Subversion always 
fetches the latest revision at that URL.

> > And if every svn:externals URL included the
> > exact version of the other project to include, aren't svn:externals
> > then more-or-less like the subproject link support, except they
> > also include the URL?
>
> Just to clarify, my point was just that Andy's setup seems to assume
> that the externals don't specify a revision.  If they do, maybe

They don't.  If they did, they'd be just as useful as git's submodules.

> git-svn can map the externals into subprojects.  Is this what
> you're thinking?

Well, I'm thinking that that information /can/ be reconstructed from the 
revision date information - kind of - the problem is that there is no 
way to know when the parent updated the module.   svn:externals really 
is just a quick way of doing
 $ cd submodule
 $ svn update
That's it.  That's all you get.  We could guess that when the parent 
module was at date YYYY-MM-DD, that the submodule would be at that same 
date - but who knows?



Andy
-- 
Dr Andy Parkins, M Eng (hons), MIET
andyparkins@gmail.com