Javalin: getOrNull not giving a null value

[simpleauthority]

Actual behavior (the bug)
I have optional/required parameters for a specific route. I use getOrNull by default to either get the value or get null in its place. Then, I check if optional is true and if value is null. If so, I just return null from my handler. However, my route execution is short-circuited by getOrNull and Postman has:

{
    "title": "Form parameter 'name removed' with value 'null' invalid - Failed check",
    "status": 400,
    "type": "https://javalin.io/documentation#badrequestresponse",
    "details": []
}

Expected behavior
I expect to be able to work with null.

To Reproduce
Call getOrNull with a parameter that is supposed to be allowed to be null.

Additional context
Code I'm using:

String resolved = validator.getOrNull(); // I am short-circuited here if it is null and I do not reach the if.
if (optional && resolved == null) {
    return null;
} else if (resolved != null) {
    return parser.parse(resolved);
}

I'm not very proficient in Kotlin, though I do use it on occasion. This doesn't look right to me, but I could be wrong.

fun getOrNull(): T? = rules
        .find { value == null || !it.test.invoke(value) }
        ?.let { throw BadRequestResponse(it.invalidMessage) }
        ?: value

It seems that if the value is null, the ?.let {} will run and throw a 400 Bad Request. The value is only returned if it isn't null. (Edit: verified with debugger)

I am not sure of anything else, but if you need more please let me know and I will get the information for you.

[tipsy]

This function was recently added by @oharaandrew314, maybe he knows what's up?

[oharaandrew314]

@simpleauthority, I was able to reproduce the error you describe, but I'd like to confirm that the causes are the same.

Was your validator created for a query param with at least one check added to it?

[simpleauthority]

@oharaandrew314 Form param, but yes at least one check was added.

[oharaandrew314]

I'll add a test for that to make sure it's fixed.

On Wed., Jul. 10, 2019, 7:35 p.m. Jacob Andersen, [e-mail]
wrote:

@oharaandrew314 https://github.com/oharaandrew314 Form param, but yes
at least one check was added.

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[simpleauthority]

Thank you for your prompt work on this @oharaandrew314. It is appreciated.

[simpleauthority]

To be thorough, it may also be wise to add a test for path params that can be omitted (null) with checks added.