Best way to modify code without breaking stuff.

[Ivan Illarionov]

On Wed, 04 Jun 2008 00:25:19 -0700, Jesse Aldridge wrote:

> I've got a module that I use regularly.  I want to make some extensive
> changes to this module but I want all of the programs that depend on the
> module to keep working while I'm making my changes.  What's the best way
> to accomplish this?

Version control system.

http://en.wikipedia.org/wiki/List_of_revision_control_software

Make your module a versioned repository.
Make your changes in different place, then commit them.

I use SVN and mercurial.

Ivan