More specifically, I'm thinking about two different modes of development for a library (private to the company) that's already relied upon by other libraries and applications:
- Rapidly develop the library "in isolation" without being slowed down by keeping all of the users in sync. This causes more divergence and merge effort the longer you wait to upgrade users.
- Make all changes in lock-step with users, keeping everyone in sync for every change that is made. This will be slower and might result in wasted work if experimental changes are not successful.
As a side note: I believe these approaches are similar in spirit to the continuum of microservices vs monoliths.
Speaking from recent experience, I feel like I'm repeatedly finding that users of my library have built towers upon obsolete APIs, because there have been multiple phases of experimentation that necessitated large changes. So with each change, large amounts of code need to be rewritten.
I still think that approach #1 was justified during the early stages of the project, since I wanted to identify all of the design problems as quickly as possible through iteration. But as the API is getting closer to stabilization, I think I need to switch to mode #2.
How do you know when is the right time to switch? Are there any good strategies for avoiding painful upgrades?
I don't have multi-user library maintenance experience in particular, but
I think a library with multiple users has to have a particular consideration for them.
I think "keeping all users in sync" is a hard ask that will likely cause conflict and frustration (on both sides). I don't know your company or project landscape though. Just as a general, most common expectation.
So between your two alternatives, I guess it's more of point 1? I don't think it should be "rapidly develop" though. I'm more thinking doing mindful "isolated" lib development with feedback channels, somewhat predictable planning, and documented release/upgrade changes.
If you're not doing mindful thorough release management, the "saved" effort will likely land elsewhere, and may very well be much higher.