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?
Users will become dependent on anything you release.
Microsoft has to be careful with private and internal members as users will use reflection and become dependent on them. Meaning internal changes break customer code.
Admittedly that is over kill in most cases. I take the stance if they are dependent on private state it’s their fault if a release breaks it.
But the point remains you can’t easily change existing APIs once released.
As mentioned above semantic versioning is a good solution to this. At least then they know when an upgrade will cause breaking changes.
If it can be avoided don’t put out anything that will likely be retired. Releasing experimental features that are likely to be replaced is always going to be bad.
If you release a feature you need to plan to support it essentially.