ExtensionContext: How to properly search in parent contexts?

[bmarwell]

Hi!

With my extensions (not just in this example), I do some initialisation in the beforeAll method and some fine-tuning (e.g. finding execution arguments) in the beforeEach method.

I was using context.getParent() for this: https://github.com/bmarwell/jdtfmt/blob/main/integration-tests/it-extension/src/main/java/io/github/bmarwell/jdtfmt/its/extension/JdtFmtExtension.java#L83

However, @sormuras hinted me to getRoot(): https://docs.junit.org/current/user-guide/#extensions-keeping-state

Blindly using getParent() seems a little fragile, and not sure if there is a way to search all the layers in between.

What is the recommended approach? Is it always true that the beforeAll context is the direct parent of beforeEach?
Maybe the javadoc should mention such things (when to use which context, when to call getParent/getRoot, which one is fragile, etc.).

Thanks!

[sormuras]

@jlink answered a related question here: https://stackoverflow.com/questions/58586207/how-to-store-values-in-junit-5-extensions-and-inject-in-parameterized-test#comment103705894_58586208

Perhaps an Optional<Store> findStore(NAMESPACE) function would be good to have. Search the current context first, and the delegating to all parents, including and ending with the root context.