Restore options.scenarios

[codebien]

Using as an example the following script, it prints an unexpected {} object using >v0.37.0. This change has been introduced by #2392.

import exec from 'k6/execution';

export const options = {
	scenarios: {
		contacts: {
			executor: 'shared-iterations',
			iterations: 1,
		},
	},
};

export default function() {
	console.log(JSON.stringify(options.scenarios))
}

In v0.36.0 and previous versions, the scenarios key wasn't set during the js.Bundle.Instantiate because the key used for it was scenarios,omitempty.

The current change is an hack for restoring the previous behaviour where the expected output is:

INFO[0000] {"contacts":{"executor":"shared-iterations","iterations":1}}  source=console

Questions

• Could we rid the entire b.Options.ForEachSpecified("json", logic when k6/execution: Export consolidated options #2450 will be implemented. If yes, probably we should directly implement 2450 and not merge this.
• Do we have an alternative to make this change less const-string dependent?

[mstoykov]

This unfortunately means that we won't set the scenarios in the script at all, so if they are not entirely configured from within they will have wrong values ...

It seems to me like the Set doesn't work correctly and it seems to be some goja issue - probably due to dop251/goja#377 (the type definition).

[mstoykov]

Suggested change

	return
	val = (map[string]lib.ExecutorConfig)(val.(lib.ScenarioConfigs))

This seems like a better fix.
We basically remove the type "around" map and give goja a map which then is set correctly.

This definitely needs a bunch of tests though

[mstoykov]

Probably a better variant will be for this to have some kind of interface ToValue or something like that. Then we can check that val implements it and call the method to get the actual value - the body in this will be this same line.

But I feel that this might be too much work especially as this will likely be the only "exception" so maybe leave that as a comment and hope that we will never have to implement it 🤞

[codebien]

Unfortunately, this doesn't work really well because it includes the BaseConfig that the executor's config contains. The ideal approach would be to use a mapper like ToValue to return the correct object.

[codebien]

Considering the effort required for this, we would directly introduce the final and better solution. I opened an issue for tracking and future updates. #2495