PolyglotException when cocatenating String with HashMap

[vepo]

I'm trying to migrate a legacy Nashorn + Java 8 project to use GraalVM. As a first step, we are migrating to use GraalVM.js.

When migrating some scripts I found that some of our prints were throwing an exception. This exception happens when we have the following script.

function fn(somePojo, someHashMap) {
    print('' + somePojo.toString()); // It works fine
    print('' + someHashMap.toString()); // It works fine
    print('' + somePojo); // It works fine
    print('' + someHashMap); // Throws org.graalvm.polyglot.PolyglotException
    return 'true';
}

This is a sample code (https://github.com/vepo/graalvm-bug) that for testing. The same exception was thrown when running it with OpenJDK 8 and 20.

[WARNING]
javax.script.ScriptException: org.graalvm.polyglot.PolyglotException: TypeError: (this) has no such function "valueOf"
    at com.oracle.truffle.js.scriptengine.GraalJSScriptEngine.toScriptException (GraalJSScriptEngine.java:483)
    at com.oracle.truffle.js.scriptengine.GraalJSScriptEngine.invokeFunction (GraalJSScriptEngine.java:558)
    at io.vepo.graalvmjs.GraalVmJsBug.main (GraalVmJsBug.java:52)
    at org.codehaus.mojo.exec.ExecJavaMojo$1.run (ExecJavaMojo.java:279)
    at java.lang.Thread.run (Thread.java:1623)
Caused by: org.graalvm.polyglot.PolyglotException: TypeError: (this) has no such function "valueOf"
    at <js>.fn (<eval>:5)
    at org.graalvm.polyglot.Value.execute (Value.java:841)
    at com.oracle.truffle.js.scriptengine.GraalJSScriptEngine.invokeFunction (GraalJSScriptEngine.java:556)
    at io.vepo.graalvmjs.GraalVmJsBug.main (GraalVmJsBug.java:52)
    at org.codehaus.mojo.exec.ExecJavaMojo$1.run (ExecJavaMojo.java:279)
    at java.lang.Thread.run (Thread.java:1623)

[iamstolis]

What version of GraalVM/graaljs do you use? I was able to reproduce this issue in some older GraalVM relase but your test-case works fine in the latest release (GraalVM 22.3.x) or with the latest development version.

[vepo]

Ow! I was using some old version!

Sorry for that. I should always remember to check with the latest version. 🤦‍♂️