DAG output does not include channel name for multiMap

[GordianDziwis]

Bug report

DAG output does not include channel name for multiMap.

Root node is defined by:

chowlkDiagrams = Channel.fromPath(params.sourceDir + '/*.xml')
    .multiMap { it -> toTtl: toPng: it }

Workaround is to define the channel in two steps with different names:

test = Channel.fromPath(params.sourceDir + '/*.xml')
chowlkDiagrams = test.multiMap { it -> toTtl: toPng: it }

Now test is shown, but chowlkDiagrams is still missing:

Environment

• Nextflow version: [21.04.0.5552]
• Java version: [openjdk 11.0.11 2021-04-20]
• Operating system: [ubuntu 21.04]
• Bash version: zsh 5.8 (x86_64-ubuntu-linux-gnu)