[Bug]: NullPointerException when invoking a service resource with optional parameter containing keyword

[anuruddhal]

Description

Invoking the following getPackage resource without limit results in a null pointer exception.

import ballerina/http;

listener http:Listener webAPIEP = new (9090);

service / on webAPIEP {

    isolated resource function get packages(int? 'limit = (), string? package = (), boolean? user\-packages = false) returns http:Ok|http:BadRequest|http:InternalServerError|http:Unauthorized {
        return <http:Ok>{
            body: "hello"
        };
    }

}

Following curl results in a null pointer.

curl http://localhost:9090/packages\?package=jbl

[2023-07-19 14:55:42,625] SEVERE {b7a.log.crash} - null
java.lang.NullPointerException
	at bctestorg.hellowin.0.creators.$_function_calls.call(Unknown Source)
	at bctestorg.hellowin.0.$_init.call(hellowin)
	at io.ballerina.runtime.internal.scheduling.AsyncUtils.lambda$callDefaultValueFunction$0(AsyncUtils.java:218)
	at io.ballerina.runtime.internal.scheduling.SchedulerItem.execute(SchedulerItem.java:54)
	at io.ballerina.runtime.internal.scheduling.Scheduler.run(Scheduler.java:306)
	at io.ballerina.runtime.internal.scheduling.Scheduler.runSafely(Scheduler.java:273)
	at java.base/java.lang.Thread.run(Thread.java:829)

error: java.lang.NullPointerException

Invoking with limit parameter works.

curl http://localhost:9090/packages\?limit\=1\&package=jbl
hello%

Steps to Reproduce

No response

Affected Version(s)

2201.7.0

OS, DB, other environment details and versions

No response

Related area

-> Runtime

Related issue(s) (optional)

No response

Suggested label(s) (optional)

No response

Suggested assignee(s) (optional)

No response

[HindujaB]

The issue happens due to this change
adb7633

[github-actions]

This issue is NOT closed with a proper Reason/ label. Make sure to add proper reason label before closing. Please add or leave a comment with the proper reason label now.

      - Reason/EngineeringMistake - The issue occurred due to a mistake made in the past.
      - Reason/Regression - The issue has introduced a regression.
      - Reason/MultipleComponentInteraction - Issue occured due to interactions in multiple components.
      - Reason/Complex - Issue occurred due to complex scenario.
      - Reason/Invalid - Issue is invalid.
      - Reason/Other - None of the above cases.