How to handle async adapters?

[s1n7ax]

Discussed in #322

^{Originally posted by s1n7ax November 19, 2023}
I'm working on https://github.com/nvim-java/nvim-java. So far, I have created only two APIs to run tests.

• run_current_test_class
• debug_current_test_class

Both these are ran using nvim-dap & test discovery is done by communicating to jdtls language server.

However, I would like to have an adapter so I can get all the neotest features come with it. However, I don't really understand how to do asynchronous stuff from the given adapter interface. I can see that you have the @async annotation in each method, however, there is no callback function passed to any APIs.

So I would like to get help on

• doing async stuff
  For instance, there is a language sever command for checking if the given file is a test or not in jdtls. It's java.project.isTestFile. However calling this has to be done asynchronously. So my adapter function should look like this with a callback function. But looking at the interface there is not? So how should this be handled?

adapter.is_test_file = function(file_path, callback)
	jdtls.executeCommand({
		command = 'java.project.isTestFile',
		arguments = { uri },
	}, function(err, is_test_file)
		assert(err, 'could not check the file')

		callback(is_test_file)
	end)
end

• What should build_spec return? Is it a dap laucher config?

[rcarriga]

Closing and continuing in discussion linked