No permissions to trigger downstream pipeline

Summary

An upstream project with a trigger to downstream projects returns error: No permissions to trigger downstream pipeline

Steps to reproduce

1. Create an upstream project
2. Create a downstream project
3. Create an upstream pipeline to trigger downstream pipeline
4. Start the upstream pipeline with a user who has developer rights on the downstream project

Example Project

• https://gitlab.com/NebulousLabs/Sia
• https://gitlab.com/NebulousLabs/Sia-Ant-Farm

What is the current bug behavior?

We have an upstream project: https://gitlab.com/NebulousLabs/Sia

with trigger in gitlab-ci.yml:

antfarm-version-tests:
  stage: test
  trigger:
    project: NebulousLabs/Sia-Ant-Farm
    strategy: depend
  variables:
    PARENT_CI_PIPELINE_SOURCE: $CI_PIPELINE_SOURCE
  only:
    - master

According to the documentation from: https://docs.gitlab.com/ee/ci/multi_project_pipelines.html#triggering-a-downstream-pipeline-using-a-bridge-job

The user that created the upstream pipeline needs to have access rights to the downstream project (my/deployment in this case). If a downstream project is not found, or a user does not have access rights to create a pipeline there, the staging job is marked as failed.

The user: https://gitlab.com/pjbrone who started the upstream pipeline: https://gitlab.com/NebulousLabs/Sia/-/pipelines/244881112

has permissions to start a downstream pipeline, example pipeline he has started manually: https://gitlab.com/NebulousLabs/Sia-Ant-Farm/-/pipelines/244936968

Gets error: No permissions to trigger downstream pipeline in the upstream pipeline.

What is the expected correct behavior?

Downstream pipeline is triggered correctly.

Relevant logs and/or screenshots

https://gitlab.com/NebulousLabs/Sia/-/pipelines/244881112 antfarm-version-tests job fails with a permission error

Output of checks

This bug happens on GitLab.com

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:env:info`)

(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`)

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)
(we will only investigate if the tests are passing)

Possible fixes