"cross_dependency" mysterious CI error

Long story short, I have a pipeline that 1. generates some yml dynamically and 2. triggers that pipeline as a child. This “child pipeline” is a single job that’s essentially running a bunch of other (variable amount) of pipelines

The term “variable count” refers to the fact that the number of “items” is determined at runtime.

FILE: .gitlab-ci.yml

generate-pipeline:
  stage: generate-jobs
  rules:
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH && $CI_PIPELINE_SOURCE != "web"
  artifacts:
    public: false
    name: "auto job group unreal ci yml"
    paths:
      - "dynjobs/"
      - ".gitlab-ci-group-run.yml"
  script:
    # some script that generates all the variable count jobs in the "dynjobs" folder.
    # the number of jobs created in "dynjobs" is determined at runtime.
    # also generates the ".gitlab-ci-group-run-yml" from the "template file" below.

run-pipeline:
  stage: run-jobs
  rules:
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH && $CI_PIPELINE_SOURCE != "web"
  variables:
    PARENT_PIPELINE_ID: $CI_PIPELINE_ID
  needs: ['generate-pipeline']
  trigger:
    include:
      - artifact: .gitlab-ci-group-run.yml
        job: generate-pipeline
    strategy: depend

FILE: template file

run-group-pipeline:
  rules:
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH && $CI_PIPELINE_SOURCE != "web"
  needs:
    - pipeline: $PARENT_PIPELINE_ID
      job: run-pipeline
      artifacts: true
  trigger:
    include: 
{0}    strategy: depend

The “{0}” is filled in by a string formatter via pwsh, containing a variable amount of repeated entries of the following

- artifact: dynjobs/.gitlab-ci-dynamically-generated-stuff-1.yml
  job: generate-pipeline
- artifact: dynjobs/.gitlab-ci-dynamically-generated-stuff-2.yml
  job: generate-pipeline
- artifact: dynjobs/.gitlab-ci-dynamically-generated-stuff-3.yml
  job: generate-pipeline
# etc

The relationships here seem sound to me, HOWEVER, I’m getting an odd error when I try to run this.

jobs:run-group-pipeline:needs config uses invalid types: cross_dependency

What does this mean, and how do I fix it?

Googling “cross_dependency gitlab ci” turns up 0 results, the things I see have to do with cross-project shenanigans, which isn’t relevant here.

Just to test, I also attempted to comment out trigger,include,strategy, and all the dynamic -artifact/job lines in the generated file “.gitlab-ci-group-run.yml” and add a test script like

script:
  - echo "Hello World!"
  - dir
  - cd dynjobs
  - dir

and everything (all the dynamically generated yml files in the dynjobs folder, and also the “.gitlab-ci-group-run.yml” file show up as expected, along with the repo contents.

This indicates to me that the pipeline in the “.gitlab-ci-group-run.yml” is getting evaluated/“executed” in some sense, it’s just that when doing the trigger/include/artifact,job*N,strategy thing causes issues for some reason.

I even modified the template file to simply have something like

trigger:
  include:
    - .gitlab-ci-test-a.yml
    - .gitlab-ci-test-b.yml

where these two a & b files are simple pipeline files in the repo that just echo something, and they both get executed fine.

Thank you for your time!