API Difference Linting

[roxspring]

Several times colleagues have asked whether our CI integration could use Zally to block new SHOULD violations being introduced by a branch while letting existing SHOULD violations through. Similarly, I've wondered a couple of times about automatically identifying breaking changes to APIs.

Both of these cases go well beyond simple linting and would need a new mode where both new and baseline versions of a spec are submitted. Validating each spec separately and diffing the Violations would probably work for the first case. For the second I imagine configurable rules for the second, depending on whether changes should be allowed to security scopes, paths, operations, schemas etc.

Is there any appetite for Zally to take on these additional capabilities?

Or are there some good recommendations of existing tools to achieve these results?

[maxim-tschumak]

I would separate these two features.

1. Incremental linting - Diff between two violation reports Personally, I don't believe this is very useful, but if you have a use-case for this - let's implement it.

2. Breaking change detection I think it can provide huge value for the users. We already had this idea, but unfortunately could not get to it. We should start by identifying the classes of backward incompatible changes.