**Description**

For a DAG that looks like this:

```
A >> B
```

If A fails, B goes into "upstream_failed" state. If a user then marks A "success", B will remain in "upstream_failed" state. It will not automatically start running. This scenario often happens if the failure of A is dealt with outside of Airflow and the user does not want Airflow to run A again. But he usually expect Airflow to run B after A is marked "success".

**Use case / motivation**

After A is marked "success", its downstream tasks B should be cleared automatically and get ready to be scheduled. To avoid changing this behaviour completely, there can be a toggle button next to "Success" that lets the user decide if he wants Airflow to automatically clear downstream tasks that are in "upstream_failed" state.
tests/www/views/test_views.py
conf = initialize_config()
    conf.validate()
    with conf_vars({('webserver', 'expose_config'): 'True'}):
        resp = admin_client.get('configuration', follow_redirects=True)
    check_content_in_response(['Airflow Configuration', 'Running Configuration'], resp)
def test_redoc_should_render_template(capture_templates, admin_client):
    with capture_templates() as templates:
        resp = admin_client.get('redoc')
        check_content_in_response('Redoc', resp)
    assert len(templates) == 1
    assert templates[0].name == 'airflow/redoc.html'
    assert templates[0].local_context == {
        'openapi_spec_url': '/api/v1/openapi.yaml',
        'rest_api_enabled': True,
    }
def test_plugin_should_list_on_page_with_details(admin_client):
    resp = admin_client.get('/plugin')
    check_content_in_response("test_plugin", resp)
    check_content_in_response("Airflow Plugins", resp)
    check_content_in_response("source", resp)
    check_content_in_response("<em>$PLUGINS_FOLDER/</em>test_plugin.py", resp)
def test_plugin_should_list_entrypoint_on_page_with_details(admin_client):