updating a patch to the new version of a program

Question

I have this patch developed for mailman-2.1.13, and I would like to port it to mailman-2.1.15

I never did this before, so I'm asking for advices here. How would you go about this task ? Here are my thoughts on the subject :

• I could search the 2.1.15 codebase for code segments corresponding to the patch, but I would miss any new part depending on the patched code.
• I could look at the diff between 2.1.13 and 2.1.15 and search for parts conflicting with the patch, at the risk of drowning into the many changes between the versions
• I could simply rewrite the patch but I would need to understand all the logic of the patched application, which could be quite long ...

Your advices are welcome !

Answer 1

The keywords for search are "rebase", "merge" and "conflict".

A conflict occurs when different parties make changes to the same document, and the system is unable to reconcile the changes. A user must resolve the conflict by combining the changes, or by selecting one change in favour of the other.

You would find that resolving conflicts (e.g. porting patch to newer version) is usually not trivial operation and cannot be done correctly without deep understanding of code you work with.

Really depends on the change in main code base from mailman-2.1.13 to mailman-2.1.15, but sometimes it is easier to rewrite patch from scratch, sometimes it is sufficient to merge changes from patch to new version and try to fix the conflicts/problems it makes.

I would start with finding out what was the original problem that patch wanted to solve and how it was solved. Then look to 2.1.15 code and find out if the original problem is still there and if it is possible to apply the patch directly (internals didn't change so much in meantime) or new approach must be applied.