[BUG] Cannot invoke "String.length()" because "spec" is null

[polastre]

Description

This error is thrown at the end of my workflow, but I can't figure out why. I will try to create a simplified workflow.js to reproduce, but wanted to start by asking if anyone has ideas.

Environment

• OS: Linux
• Java: JDK 21

Steps to Reproduce

Run baremaps workflow execute --file=workflow.js

Error

[ERROR] 2025-09-23 00:23:49.602 [main] WorkflowExecutor - Error while executing the workflow
java.util.concurrent.CompletionException: org.apache.baremaps.workflow.WorkflowException: java.net.MalformedURLException: Cannot invoke "String.length()" because "spec" is null
        at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:315) ~[?:?]
        at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:320) ~[?:?]
        at java.base/java.util.concurrent.CompletableFuture$UniRun.tryFire(CompletableFuture.java:791) ~[?:?]
        at java.base/java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:482) ~[?:?]
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[?:?]
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[?:?]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
Caused by: org.apache.baremaps.workflow.WorkflowException: java.net.MalformedURLException: Cannot invoke "String.length()" because "spec" is null
        at org.apache.baremaps.workflow.WorkflowExecutor.lambda$createStep$3(WorkflowExecutor.java:172) ~[baremaps-core-0.8.2.jar:0.8.2]
        at java.base/java.util.concurrent.CompletableFuture$UniRun.tryFire(CompletableFuture.java:787) ~[?:?]
        ... 4 more
Caused by: java.net.MalformedURLException: Cannot invoke "String.length()" because "spec" is null
        at java.base/java.net.URL.<init>(URL.java:806) ~[?:?]
        at java.base/java.net.URL.<init>(URL.java:654) ~[?:?]
        at java.base/java.net.URL.<init>(URL.java:590) ~[?:?]
        at org.apache.baremaps.tasks.DownloadUrl.execute(DownloadUrl.java:74) ~[baremaps-core-0.8.2.jar:0.8.2]
        at org.apache.baremaps.workflow.WorkflowExecutor.lambda$createStep$3(WorkflowExecutor.java:167) ~[baremaps-core-0.8.2.jar:0.8.2]
        at java.base/java.util.concurrent.CompletableFuture$UniRun.tryFire(CompletableFuture.java:787) ~[?:?]
        ... 4 more
Caused by: java.lang.NullPointerException: Cannot invoke "String.length()" because "spec" is null
        at java.base/java.net.URL.<init>(URL.java:712) ~[?:?]
        at java.base/java.net.URL.<init>(URL.java:654) ~[?:?]
        at java.base/java.net.URL.<init>(URL.java:590) ~[?:?]
        at org.apache.baremaps.tasks.DownloadUrl.execute(DownloadUrl.java:74) ~[baremaps-core-0.8.2.jar:0.8.2]
        at org.apache.baremaps.workflow.WorkflowExecutor.lambda$createStep$3(WorkflowExecutor.java:167) ~[baremaps-core-0.8.2.jar:0.8.2]
        at java.base/java.util.concurrent.CompletableFuture$UniRun.tryFire(CompletableFuture.java:787) ~[?:?]
        ... 4 more

[polastre]

Looks like this is an artifact of migrating my workflow from baremaps 0.7x to 0.8.x. I missed that url became source and path became target. When big config changes like this are done in the future, would be helpful to have a migration guide or notes in the changelog. Better errors from org.apache.baremaps.workflow would be nice too with the exact step that is failing.

[bchapuis]

@polastre If I understand correctly, you have been able to adapt the workflow.

Sorry for not communicating these upgrades and migrations clearly. I sometimes move too quickly due to time constraints. I usually try to onboard people through the mailing list during the release process. We could typically include this feedback in the release notes if we encounter problems with the new binaries when testing production configurations.

I will include a note in the release process regarding this point.