Child pipeline fails if there is no job on the current branch
Summary
One of my client is working with mono-repo for java software. I recently use child-pipelines to build docker image and deploy them into kubernetes clusters. (btw it allow me to significantly reduce the size of my .gitlab-ci.yaml file so i'm really happy of this feature, my code also more respect DRY principle) But unfortunately my child-pipeline fail if there is no job to be done in a specific branch.
Steps to reproduce
In my current workflow, I only do packaging/deployment on branches : develop,release,master So when the CI run from a feature-* branch there is nothing to do in my child pipeline, and the parent job failed with the error "Downstream pipeline can not be created".
Example Project
Hosted gitlab, so no example sorry.
What is the current bug behavior?
The parent job failed.
What is the expected correct behavior?
If there is nothing to do, there is no error, like a classic pipeline.
Results of GitLab environment info
Hosted gitlab version 12.10.3-ee setup with helm chart version 3.3.3