[InfiniteRand]

I could see some uses for something like this. When I was working as a web programmer, I often had to do a lot if dev-server type things. Since at least one of the dev-server was often on my personal machine, it could often be a very different beast than the production server.

I guess what this really is a matter of is configuration management, for certain configurations you will have certain lines of code that will not matter or that will confuse. While you can manage this within your code in various ways (such as the #ifdef _DEBUG macro, etc.), it would be natural for the VC to handle this.

For a general features, maybe you could either specify in a configuration file, particular lines of a file or a regular expression to designate lines to ignore or better yet to only apply to certain branch checkouts.

A nice feature to think about for my "one-of-these-days-I-will-make-a-beter-version-control-system" file.

[_ikke_]

Why not just keep environment dependent settings in a separate file that is not tracked? Then you have no problem with files that are 'half-tracked'.