MacOS X/NeXT "bundles"

["Alastair J.Houghton" <aj...@dsl.pipex.com>]

On Apple's Cocoa-dev mailing list recently there have been a couple of 
interesting comments from Chris Hanson about problems with storing 
version control information in directories in the source tree (like CVS 
or Subversion).  In particular, on NeXT-derived platforms (as well as 
Acorn Archimedes I seem to remember), there are objects ("bundles") 
that look like files from the GUI, but are in fact directories with a 
special subdirectory hierarchy and special contents.

This would be fine, but for the fact that applications sometimes treat 
them exactly the way they would have treated a file... for example, 
when saving, they might do the following:

	1. Create a new bundle, with a different name.

	2. Delete the old bundle.

	3. Rename the new bundle so it has the original name.

(Just like a typical "safe" file save routine.)

Trouble is, this procedure trashes Subversion/CVS's version control 
information, which wouldn't have happened if it were just a file.  Now, 
in the case of the example Chris gave (EOModeler, part of Apple's 
WebObjects software), Apple have apparently changed their program to 
cope with CVS, and will presumably at some point have to do so again to 
cope with Subversion (depending on exactly what they changed).

It would seem sensible if Subversion and CVS could provide version 
control support for such an object without having to change existing 
applications; Chris's idea was to add options to hold version control 
information outside of the source tree, but I personally don't think 
this is a good idea because of the advantages of having it there.  
Perhaps a better solution would be to store version control information 
for bundles in the containing directory... e.g. given a tree like the 
following:

	my-project/
		my-bundle.ext/
			Contents/
				Info.plist
				Version.plist
				Resources/

	(which looks like a single file, my-project/my-bundle.bundle, from the 
GUI)

a checked-out copy from CVS might look like

	my-project/
		CVS/
			Entries
			Repository
			Root			
			my-bundle.ext/
				Entries
				Contents/
					Entries
					Resources/
						Entries
		my-bundle.ext/
			Contents/
				Info.plist
				Version.plist
				Resources/

The top-level Entries file could contain an entry listing my-bundle.ext 
as a bundle.  This would of course mean changing the way CVS and 
Subversion locate their information... they'd have to keep going up the 
directory tree until they found a .svn or CVS subdirectory, then check 
that it listed the directory they had just come from as a bundle.

(I guess in Subversion, the equivalent of the Entries file would just 
list my-bundle.ext as if it were a file?  I haven't looked at 
Subversion in enough detail yet to figure-out how the working copies 
work, other than that you use them like you do in CVS.)

Anyway, I thought I'd throw this into the pot to see if anyone had any 
ideas; I might have some time soon to work on this sort of thing, so 
it's quite possible that if we have some agreement on how to handle 
this I might be able to provide a patch.

Kind regards,

Alastair.


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Re: MacOS X/NeXT "bundles"

[Chris Parker <su...@playswithfire.com>]

I'm going to trim the CC: line, since I'm not a member of the dev@ccvs
list...

On Mon, May 26, 2003 at 05:04:15PM +0100, Alastair J.Houghton wrote:
> On Apple's Cocoa-dev mailing list recently there have been a couple of 
> interesting comments from Chris Hanson about problems with storing 
> version control information in directories in the source tree (like CVS 
> or Subversion).  In particular, on NeXT-derived platforms (as well as 
> Acorn Archimedes I seem to remember), there are objects ("bundles") 
> that look like files from the GUI, but are in fact directories with a 
> special subdirectory hierarchy and special contents.
> 
> [remainder of cogent discussion clippped]

Ah! Come right over here, to ... issue 707!

http://subversion.tigris.org/issues/show_bug.cgi?id=707

At least for the bundle part. Chris' comments in
cocoa-dev@lists.apple.com aren't completely addressed by this, but it
does cover the nib/rtfd case.

Although I have to admit, having crawled around libsvn_wc to get a feel
for what this would take its current designation as "bite-sized"
might be taken with a grain of salt...

.chris

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