NPE in TextDocumentHandler

[aBothe]

Hey there,

I'm trying to set up a LanguageServer having a custom DefinitionHandler.
This handler currently features a DefinitionRegistrationOptions config object with a DocumentSelector set to null (it's just still the default - I'll define it soon).

When trying to start the LanguageServer in one of my tests, it just didn't want to fully initialize.
I manually stepped through LanguageServer code to find out what's throwing an exception there.

Turns out, it's an NullPointerException in TextDocumentHandler.GetHandler:

csharp-language-server-protocol/src/Server/Matchers/TextDocumentMatcher.cs

Line 82 in 79b1056

if (registrationOptions?.DocumentSelector == null || registrationOptions.DocumentSelector.IsMatch(attributes))

There might be a ? missing in the second clause, as it's evaluating said second expression as soon as registrationOptions is not null - but DocumentSelector might be.

My code was:

public DDefinitionHandler(ProgressManager progressManager)
            : base(new DefinitionRegistrationOptions(), progressManager)
        {
        }

Thanks for your project!

[david-driscoll]

Thanks @aBothe

I think you might be right, it's very possible the registrations options is null in that scenario. After this next big change I'll look at adding that in.

[david-driscoll]

I will get a fix in for this, I think it is still there looking at the code I just need to create a test case.

[david-driscoll]

I have added a test to my latest commit, to confirm this appears to be working as expected. Let me know if you have any more problems!