[Bug]: Getting NPE for a simple test with the Dead Code Elimination

[TharmiganK]

Description

Getting the following error when running a simple test assertion with string includes API.

This is found while checking url module with dead code elimination(Related task - ballerina-platform/ballerina-library#7339)

[2024-11-06 13:02:06,298] SEVERE {b7a.log.crash} - Cannot invoke "io.ballerina.runtime.internal.values.FPValue.getFunction()" because "<local1>" is null 
java.lang.NullPointerException: Cannot invoke "io.ballerina.runtime.internal.values.FPValue.getFunction()" because "<local1>" is null
        at tharmigan.package$test.0.tests.test.test(tests/test.bal:6)
        at tharmigan.package$test.0.lambdas.$_generated1tests.test_execute-generated_1.test$lambda0$(tests/test_execute-generated_1.bal:4)
        at io.ballerina.runtime.internal.scheduling.SchedulerItem.execute(SchedulerItem.java:54)
        at io.ballerina.runtime.internal.scheduling.Scheduler.run(Scheduler.java:324)
        at io.ballerina.runtime.internal.scheduling.Scheduler.runSafely(Scheduler.java:291)
        at java.base/java.lang.Thread.run(Thread.java:840)

Steps to Reproduce

Try to run the following test with dead code elimination feature:

import ballerina/test;

@test:Config
function test() {
    string result = "a";
    test:assertTrue(result.includes(" "));
}

Compiling source
        tharmigan/package:0.1.0
Duration for unused BIR node analysis : 1ms
    tharmigan/package:0.1.0 : 1ms


Running Tests

        package
[2024-11-06 13:02:06,298] SEVERE {b7a.log.crash} - Cannot invoke "io.ballerina.runtime.internal.values.FPValue.getFunction()" because "<local1>" is null 
java.lang.NullPointerException: Cannot invoke "io.ballerina.runtime.internal.values.FPValue.getFunction()" because "<local1>" is null
        at tharmigan.package$test.0.tests.test.test(tests/test.bal:6)
        at tharmigan.package$test.0.lambdas.$_generated1tests.test_execute-generated_1.test$lambda0$(tests/test_execute-generated_1.bal:4)
        at io.ballerina.runtime.internal.scheduling.SchedulerItem.execute(SchedulerItem.java:54)
        at io.ballerina.runtime.internal.scheduling.Scheduler.run(Scheduler.java:324)
        at io.ballerina.runtime.internal.scheduling.Scheduler.runSafely(Scheduler.java:291)
        at java.base/java.lang.Thread.run(Thread.java:840)
 

        test has failed.


                [fail] test:

                    error("java.lang.NullPointerException: Cannot invoke "io.ballerina.runtime.internal.values.FPValue.getFunction()" because "<local1>" is null")
                                callableName: test moduleName: tharmigan.package$test.0.tests.test fileName: tests/test.bal lineNumber: 6
                                callableName: test$lambda0$ moduleName: tharmigan.package$test.0.tests.test_execute-generated_1 fileName: tests/test_execute-generated_1.bal lineNumber: 4



                0 passing
                1 failing
                0 skipped

                Test execution time : 0.048s
error: there are test failures

Affected Version(s)

Ballerina SwanLake Update 11(2201.11.x)

OS, DB, other environment details and versions

No response

Related area

-> Compilation

Related issue(s) (optional)

No response

Suggested label(s) (optional)

No response

Suggested assignee(s) (optional)

No response

[MaryamZi]

Seems to be happening with langlib function calls.

Reproducible when the function is in the source too, rather than tests.

Source

public function includesFn(string a, string b) returns boolean {
    return a.includes(b);
}

Tests

import ballerina/test;

@test:Config
function test() {
    boolean res = includesFn("foo", "bar");
    test:assertFalse(res);
}

Issue could be related to io.ballerina.projects.UsedBIRNodeAnalyzer.InvocationData#registerNodes since the function pool is not populated for langlibs.

[MaryamZi]

Seems like the error goes away when the start index is provided.

E.g.,

return a.includes(b, 4);

[MaryamZi]

We've added some fixes which are available with 2201.11.0-20241111-101700-af28a18f, can you please check with this version?

[TharmiganK]

We've added some fixes which are available with 2201.11.0-20241111-101700-af28a18f, can you please check with this version?

With the provided timestamped version, the tests are running without any NPE issues. Hence closing this issue

[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.