The Envy configuration management system for Smalltalk worked like this. As you were working, you could see if someone had changed code "nearby" (same class, sa

The Envy configuration management system for Smalltalk worked like this. As you were working, you could see if someone had changed code "nearby" (same class, same category, same protocol) and you could review it and merge it in. Perforce provides something with the same effect. If you periodically get the most recent revision, you can see files with collisions in your change sets, then merge them in.