The workflow_run event occurs when a workflow run is requested or completed, and allows you to execute a workflow based on the finished result of another workflow.

example

on:
workflow_run:
  workflows: [ test ]
  types: 
    - completed

However by itself, this doesn't quite work as expected.

1. The completed type, does not indicate success, for that you'd have to include the following in each job of your workflow:

   if: ${{ github.event.workflow_run.conclusion == 'success' }}
   

2. If you're depending on more than one workflow, then ANY of them completing, will trigger the event

   example

   name: deploy
   
   on:
   workflow_run:
     workflows: [ test, lint, compile ]
     types: 
       - completed
   

   if your test workflow fails, but lint completed successfully, github.event.workflow_run.conclusion == 'success' will still be true

3. Your workflow will trigger as many times as you have workflow dependencies

   > _in the previous example, our `deploy` workflow, will run 3 times!_
   

   All this makes the workflow_run event fundamentally broken for any advanced usage, this Action aims to remedy that.

   Note: See this Community discussion for more info on the topic