WRROC fails with NullPointerException on initial run of nf-prov-test

[bentsherman]

To reproduce, clone the nf-prov repository and run the test pipeline with nf-prov 1.4.0:

nextflow run nf-prov-test

It fails with the following error:

java.lang.NullPointerException: Cannot invoke "nextflow.processor.TaskRun.getWorkDir()" because "task" is null
	at nextflow.prov.WrrocRenderer.getTaskOutputName(WrrocRenderer.groovy:916)
	at nextflow.prov.WrrocRenderer.access$10(WrrocRenderer.groovy)
	at nextflow.prov.WrrocRenderer$_render_closure25.doCall(WrrocRenderer.groovy:459)
        ...
	at nextflow.prov.WrrocRenderer.render(WrrocRenderer.groovy:456)
	at nextflow.prov.ProvObserver.onFlowComplete(ProvObserver.groovy:123)
	at nextflow.Session.notifyFlowComplete(Session.groovy:1155)
	at nextflow.Session.shutdown0(Session.groovy:749)
	at nextflow.Session.destroy(Session.groovy:694)
	at nextflow.script.ScriptRunner.shutdown(ScriptRunner.groovy:260)
	at nextflow.script.ScriptRunner.execute(ScriptRunner.groovy:146)
	at nextflow.cli.CmdRun.run(CmdRun.groovy:376)
	at nextflow.cli.Launcher.run(Launcher.groovy:503)
	at nextflow.cli.Launcher.main(Launcher.groovy:658)

On a resumed run, the wrroc manifest is created successfully. So that is a workaround for now.

@fbartusch this looks like the same error you encountered with nf-core/demultiplex 1.5.1

Fortunately now that I'm seeing it with the test pipeline, it should be easy to debug and fix.

[simleo]

I tried running nf-prov-test with nf-prov 1.4.0 and the outcome is different: the execution does not fail, but the ro-crate-metadata.json file is missing from the results directory.

$ git checkout 1.4.0
$ nextflow run nf-prov-test/ -plugins nf-prov@1.4.0

 N E X T F L O W   ~  version 25.04.6

Launching `nf-prov-test/main.nf` [prickly_montalcini] DSL2 - revision: 621cbe9a05

WARN: The legacy format is deprecated -- it will be removed in a future version
executor >  local (6)
[7f/436814] ECHO_SCRIPT (r1) [100%] 3 of 3 ✔
[23/58b99c] ECHO_EXEC (r2)   [100%] 3 of 3 ✔
WARN: Could not determine pipeline repository URL for Workflow Run RO-Crate -- launch the pipeline with canonical URL (e.g. `nextflow run nextflow-io/hello`) to ensure that the pipeline repository URL is recorded in the crate
WARN: Could not identify process definition for `ECHO_SCRIPT` -- resulting RO-Crate may be invalid (hint: define each process in a separate module script to fix this issue)
$ find . -name '*.json'
./results/manifest.json
./results/bco.json