[Bug]: java.lang.NullPointerException

[glennj]

Description

[2023-05-06 22:22:38,884] SEVERE {b7a.log.crash} - null
java.lang.NullPointerException
        at org.wso2.ballerinalang.compiler.bir.optimizer.BIROptimizer$RHSTempVarOptimizer.visit(BIROptimizer.java:159)
        at org.wso2.ballerinalang.compiler.bir.model.BIRNode$BIRBasicBlock.accept(BIRNode.java:474)
        at org.wso2.ballerinalang.compiler.bir.optimizer.BIROptimizer$RHSTempVarOptimizer.lambda$visit$3(BIROptimizer.java:121)
        at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
        at org.wso2.ballerinalang.compiler.bir.optimizer.BIROptimizer$RHSTempVarOptimizer.visit(BIROptimizer.java:121)
        at org.wso2.ballerinalang.compiler.bir.model.BIRNode$BIRFunction.accept(BIRNode.java:432)
        at org.wso2.ballerinalang.compiler.bir.optimizer.BIROptimizer$RHSTempVarOptimizer.lambda$visit$1(BIROptimizer.java:107)
        at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
        at org.wso2.ballerinalang.compiler.bir.optimizer.BIROptimizer$RHSTempVarOptimizer.visit(BIROptimizer.java:107)
        at org.wso2.ballerinalang.compiler.bir.model.BIRNode$BIRPackage.accept(BIRNode.java:89)
        at org.wso2.ballerinalang.compiler.bir.optimizer.BIROptimizer.optimizePackage(BIROptimizer.java:83)
        at org.wso2.ballerinalang.compiler.bir.BIRGen.genBIR(BIRGen.java:287)
        at io.ballerina.projects.internal.CompilerPhaseRunner.birGen(CompilerPhaseRunner.java:220)
        at io.ballerina.projects.internal.CompilerPhaseRunner.performBirGenPhases(CompilerPhaseRunner.java:157)
        at io.ballerina.projects.ModuleContext.generateCodeInternal(ModuleContext.java:451)
        at io.ballerina.projects.ModuleCompilationState$4.generatePlatformSpecificCode(ModuleCompilationState.java:132)
        at io.ballerina.projects.ModuleContext.generatePlatformSpecificCode(ModuleContext.java:385)
        at io.ballerina.projects.JBallerinaBackend.performCodeGen(JBallerinaBackend.java:170)
        at io.ballerina.projects.JBallerinaBackend.<init>(JBallerinaBackend.java:139)
        at io.ballerina.projects.JBallerinaBackend.lambda$from$0(JBallerinaBackend.java:117)
        at java.base/java.util.HashMap.computeIfAbsent(HashMap.java:1134)
        at io.ballerina.projects.PackageCompilation.getCompilerBackend(PackageCompilation.java:171)
        at io.ballerina.projects.JBallerinaBackend.from(JBallerinaBackend.java:116)
        at io.ballerina.cli.task.CompileTask.execute(CompileTask.java:191)
        at io.ballerina.cli.TaskExecutor.executeTasks(TaskExecutor.java:40)
        at io.ballerina.cli.cmd.TestCommand.execute(TestCommand.java:315)
        at java.base/java.util.Optional.ifPresent(Optional.java:183)
        at io.ballerina.cli.launcher.Main.main(Main.java:51)

ERROR [anagram:(1:1,1:1)] Compilation failed due to an unhandled exception
error: compilation contains errors

Steps to Reproduce

https://exercism.org/tracks/ballerina/exercises/anagram

code

public function anagrams(string word, string[] candidates) returns string[] {
    var toKey = function (string w) returns int[] => w.toCodePointInts().sort();
    var lcWord = word.toLowerAscii();
    var key = toKey(lcWord);

    return from string candidate in candidates
           let string lcCand = candidate.toLowerAscii()
           where lcCand != lcWord && key == toKey(lcCand)
           select candidate;
}

Affected Version(s)

$ bal version
Ballerina 2201.5.0 (Swan Lake Update 5)
Language specification 2022R4
Update Tool 1.3.14

OS, DB, other environment details and versions

$ uname -a
Linux exercism-vm 5.10.0-20-amd64 #1 SMP Debian 5.10.158-2 (2022-12-13) x86_64 GNU/Linux

Related area

-> Compilation

Related issue(s) (optional)

No response

Suggested label(s) (optional)

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Suggested assignee(s) (optional)

No response

[glennj]

A resolution:

public function anagrams(string word, string[] candidates) returns string[] {
    var lcWord = word.toLowerAscii();
    var key = keyOf(lcWord);

    return from string candidate in candidates
           let string lcCand = candidate.toLowerAscii()
           where lcCand != lcWord && key == keyOf(lcCand)
           select candidate;
}

function keyOf(string w) returns int[] => w.toCodePointInts().sort();

[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.

[glennj]

Sorry what? That I found a workaround for a language bug makes the first attempt an "engineering mistake"? My mistake or yours? Can you point me to some place in the documentation that would tell me the initial version is wrong?

[gimantha]

Sorry what? That I found a workaround for a language bug makes the first attempt an "engineering mistake"? My mistake or yours? Can you point me to some place in the documentation that would tell me the initial version is wrong?

Hey @glennj The mistake is from our side. :-). Your initial code should have worked properly, but due to a mistake (Probably we have not covered your use-case in the initial testing) done from our side, you encountered this issue. Therefore we marked it as a mistake from our side and the label is only used to categorised them as an engineering mistake done from our side. We closed the issue as we fixed the issue with this pull request: #40529

I am sorry for the confusion.

[glennj]

Thank you for your gracious reply. I overreacted to the ticket getting closed.