Best practices to deal with "slightly different" branches of source code

Question

This question is rather agnostic than related to a certain version control program.

Assume there is a source code tree under certain distributed version control. Let's call it A.

At some point somebody else clones it and gets its own copy. Let's call it B.

I'll call A and B branches, even if some version control tools have different definitions for branches (some might call A and B repositories).

Let's assume that branch A is the "main" branch. In the context of distributed version control this only means that branch A is modified much more actively and the owner of branch B periodically syncs (pulls) new updates from branch A.

Let's consider that a certain source file in branch B contains a class (again, it's also language agnostic). The owner of branch B considers that some class methods are more appropriate and groups them together by moving them inside the class body. Functionally nothing has changed - this is a very trivial refactoring of the code. But the change gets reflected in diffs. Now, assuming that this change from branch B will never get merged into branch A, the owner of branch B will always get this difference when pulling from branch A and merging into his own workspace. Even if there's only one such trivial change, the owner of branch B needs to resolve conflicts every time when pulling from branch A. As long as branches A and B are modified independently, more and more conflicts like this appear. What is the workaround for this situation? Which workflow should the owner of branch B follow to minimize the effort for periodically syncing with branch A?

Answer 1

Dev B should either un-refactor, or else add some meaningful functionality that has enough momentum to warrant merging back into A. Otherwise tell him "Them's the breaks".

To go to an extreme example, he could decide that he doesn't like C and decide to re-write everything as Pascal, line by line, using the same variable names, class names, etc.. To the point that the only difference is the language. So what would you tell him then, when he insists that there aren't any changes, so there should be no diff?

Answer 2

The owner of branch B should have discussed the change with the owner of branch A. They should have decided that either the change was worth making, in which case it should have been committed to the trunk (A) or it wasn't, in which case it should have never been made. VCS is not a substitute for communication between developers.

Answer 3

Dev B should ask Dev A to pull from him.

The situation is not avoidable if two branches diverge and never converge. Its similar to a fork in a project - Its very difficult to merge two different forks.

Answer 4

One workaround is to have a fancy diff wrapper around code comparison that will intelligently ignore certain very specific diffs.

On a simple level it's usually implemented via gdiff, on fancier, with custom diff code.

However, I must say that such a situation is really a bad thing and it's much better to merge the changes back into A; by for example submitting a patch to A's maintainers owners