Foreach is not working with Variables

[RDPerera]

Description

I built this integration where I loop through an array in a variable using foreach.

<?xml version="1.0" encoding="UTF-8"?>
<api context="/sample" name="sample" xmlns="http://ws.apache.org/ns/synapse">
    <resource methods="GET" uri-template="/">
        <inSequence>
            <variable name="arrayVar" type="JSON" value="{&quot;array&quot;:[{&quot;id&quot;:&quot;011&quot;},{&quot;id&quot;:&quot;012&quot;}]}
"/>
            <foreach collection="${vars.arrayVar.array}" parallel-execution="true" update-original="true" continue-without-aggregation="false">
                <sequence>
                    <log category="INFO" logMessageID="false" logFullPayload="false">
                        <message>${payload.id}</message>
                    </log>
                </sequence>
            </foreach>
            <respond/>
        </inSequence>
        <faultSequence>
        </faultSequence>
    </resource>
</api>

While the array values are being looped through during execution, the flow doesn't end correctly—the respond mediator is not being triggered.

Here is the error I'm getting in the output

[2025-05-07 22:48:00,708]  INFO {PassThroughListeningIOReactorManager} - Pass-through EI_INTERNAL_HTTP_INBOUND_ENDPOINT Listener started on 0.0.0.0:9201
[2025-05-07 22:48:00,723]  INFO {PassThroughListeningIOReactorManager} - Pass-through EI_INTERNAL_HTTPS_INBOUND_ENDPOINT Listener started on 0.0.0.0:9164
[2025-05-07 22:48:00,723]  INFO {StartupFinalizer} - WSO2 Micro Integrator started in 3.45 seconds
[2025-05-07 22:48:05,033]  INFO {AuthenticationHandlerAdapter} - User admin logged in successfully
[2025-05-07 22:48:08,834]  INFO {LogMediator} - {api:sample GET /sample/} 011
[2025-05-07 22:48:08,834]  INFO {LogMediator} - {api:sample GET /sample/} 012
[2025-05-07 22:48:08,837] ERROR {MediatorWorker} - {api:sample} Unexpected error executing task/async inject com.jayway.jsonpath.PathNotFoundException

Exception in thread "SynapseWorker-1" java.lang.NullPointerException: Cannot invoke "String.split(String)" because the return value of "java.lang.Exception.getMessage()" is null
	at org.apache.synapse.FaultHandler.handleFault(FaultHandler.java:85)
	at org.apache.synapse.mediators.MediatorWorker.run(MediatorWorker.java:134)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base/java.lang.Thread.run(Thread.java:1583)

Steps to Reproduce

1. Download the MI Runtime 4.4.0 and update to the latest update.
2. Create a new project and API called "sample".
3. Paste the following and try to run.

<?xml version="1.0" encoding="UTF-8"?>
<api context="/sample" name="sample" xmlns="http://ws.apache.org/ns/synapse">
    <resource methods="GET" uri-template="/">
        <inSequence>
            <variable name="arrayVar" type="JSON" value="{&quot;array&quot;:[{&quot;id&quot;:&quot;011&quot;},{&quot;id&quot;:&quot;012&quot;}]}
"/>
            <foreach collection="${vars.arrayVar.array}" parallel-execution="true" update-original="true" continue-without-aggregation="false">
                <sequence>
                    <log category="INFO" logMessageID="false" logFullPayload="false">
                        <message>${payload.id}</message>
                    </log>
                </sequence>
            </foreach>
            <respond/>
        </inSequence>
        <faultSequence>
        </faultSequence>
    </resource>
</api>

Version

Runtime Version: 4.4.0

Environment Details (with versions)

WSO2 MI VS Code Extension Version : 2.2.0

[PularaW]

Hi, I was able to recreate this and it looks interesting. Could you please assign it to me?

[vimukthiwaththegama]

Hi @RDPerera , I would like to work on this issue. Could you please assign it to me?

[Lahu19]

Hi @RDPerera, I figured out the solution for it, so could you please assign to me so i can contribute to this amazing project. under Hacktoberfest 2025

[myleshmulecraft]

Hi @RDPerera / @chanikag , I’ve recreated this issue in my local system and identified the solution. Kindly assign it to me, and I will resolve it as soon as possible.

[adityagupta0251]

Hi @RDPerera / @chanikag,

I’ve reviewed the issue and was able to reproduce the behavior locally. I’d be glad to work on this and help provide a proper fix for the foreach mediator when used with variables.

If this issue is still open for contribution, could you please assign it to me?

Thank you!