Mitigate possible NSE exception in PrivateAccessValidator.java

[jyoo980]

Issue #, if available: n/a

Description of changes:

Within PrivateAccessValidator#getPrivateAccessValiationEvent, an unchecked call to Optional#get occurs. This might throw a NoSuchElementException if the optional is indeed empty.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[mtdowling]

Thanks for submitting this. Did you run into this issue in practice? By the time this validator is invoked, all model references have been validated. Given this, I think a more tactical fix is to change the call to .get() the neighbor to use expectNeighborShape instead. This way it throws a more useful error message and doesn’t need the extra complexity. See

smithy/smithy-model/src/main/java/software/amazon/smithy/model/neighbor/Relationship.java

Line 117 in 32ff2c3

public Shape expectNeighborShape() {

[jyoo980]

Thanks for the review, @mtdowling; I didn't mean for you to look at this over the weekend, apologies.

I haven't seen the error in-practice, but it was reported by a static analysis tool after I ran a compilation locally. I'm happy to help improve the codebase if this is something you would find useful. Are there any places in the code in particular that actually might be at risk of NoSuchElementException?

[mtdowling]

Thanks for updating. Generally any place that we use .get() right now is probably fine and rather than convert to returning optionals or additional conditionals, we could switch to using these kinds of expect* style methods when available or using something like orElseThrow.

[jyoo980]

Got it, thanks! I'll fix the checkstyle errors shortly.

[mtdowling]

Thanks!