XML/vcdiff as patch file

[Bob Miller <kb...@jogger-egg.com>]

Some of us have said that we think the svn XML format would be useful
as a patch file.  I'm not so sure, though.

The original patch file, as created by "diff -c" and, later, "diff
-u", has enough redundant info that the patch can be applied to a
somewhat different base file, and patch can usually figure out how to
apply the changes.  People use this feature a lot.

The XML/vcdiff format, on the other hand, is compressed to within an
inch of its life, and has no redundancy.  If you don't have access to
the exact version of the file that the vcdiff applies to, the vcdiff
is useless.

This means that people won't be able to use XML/vcdiff files in many
of the ways they currently use patches.  Hang out on the Linux kernel
developers' list for the premier example of patch abuse, or unpack the
source RPM of a large package. (kernel-*.src.rpm is again a good
example.)

Just something to think about...

-- 
                                        K<bob>
kbob@jogger-egg.com, http://www.jogger-egg.com/

Re: XML/vcdiff as patch file

[Karl Fogel <kf...@galois.collab.net>]

Bob Miller <kb...@jogger-egg.com> writes:
> The XML/vcdiff format, on the other hand, is compressed to within an
> inch of its life, and has no redundancy.  If you don't have access to
> the exact version of the file that the vcdiff applies to, the vcdiff
> is useless.
> 
> This means that people won't be able to use XML/vcdiff files in many
> of the ways they currently use patches.  Hang out on the Linux kernel
> developers' list for the premier example of patch abuse, or unpack the
> source RPM of a large package. (kernel-*.src.rpm is again a good
> example.)
> 
> Just something to think about...

Oh, you want:

   <text-delta type="gnu-diff">[gnu diff data here...]</text-delta>

which has been discussed but not yet implemented.  Anyway, with that,
xml tree deltas as generalized patch files becomes reasonable.

When `type' is omitted, it defaults to "vcdiff" of course.

-K