Re: [xml-dev] XML/XSL Revision Control/ Source Code Versioning: Ideas, M

[Norman Gray <norman@astro.gla.ac.uk>]

Andrew (and all), hello.

On 2012 Dec 10, at 10:22, Andrew Welch wrote:

>>> Thank you for your time & responses. I remember reading somewhere that a
>>> pure text/ linear comparison based tool/ system may not be ideal to compare
>>> & merge XML tree structure based documents.
>>> 
>>> Are there any that are more XML aware?
> 
> cvs, svn, git, mercurial, rtc etc all merge xml files fine, just as
> they merge any other code.  There's nothing special about xml.

I think the 'problem' with XML is that XML-writing applications tend to act in ways which are unfriendly to text-based revision control systems.  An XML editor could legitimately change the textual form of a file, by adding newlines and other whitespace, in ways which are semantically ignorable.  More practically, XML-using tools might well write out an entire XML file in a single line.  This is still, obviously, storable in a VCS, but the diffs are useless, and it means that the file might as well be a binary blob.

I've run into this myself when trying to store application files which are in XML (in particular various applications' working files on OS X).  I did try the trick (mentioned earlier in this thread) of roughly normalising the files before checkin, so that the diffs might be sane, but this rapidly started to feel very precarious.

> Usually I'd recommend svn to start with unless you really need the
> abilities that git/hg/rtc provide (applying or removing whole change
> sets) - do you want to spend your time understanding the difference
> between a pull and rebase?  Or why you can't push because of unstaged
> files?  but...

I think those are mostly problems of git rather than Mercurial.  It's one of my objections to git that it requires you to have internalised quite a lot about its view of the world, before you can make sense of even simple actions.  Mercurial tends to have a much more civil on-ramp.

All the best,

Norman


-- 
Norman Gray  :  http://nxg.me.uk
SUPA School of Physics and Astronomy, University of Glasgow, UK