A run-history list shows a workflow that executed without any new commit, with no operator named as the actor and no external API call recorded. The workflow file declares the on block below. Which trigger most likely produced this run?
on:
push:
branches: [main]
workflow_dispatch:
schedule:
- cron: '0 6 * * 1'- AThe push event, because the run history records a commit to main even when the diff is empty and the user interface omits the pushing actor.
- BThe workflow_dispatch event, because a teammate clicked Run workflow and GitHub anonymises the actor on manually started runs to protect the operator.
- CThe repository_dispatch event, because an outside system posted a custom payload that the run history hides from the actor and commit columns by design.
- DThe schedule event, because a cron-triggered run fires on its own timetable with no commit and is attributed to the workflow rather than to any human or external caller. Correct
Why A is wrong: Tempting because push is listed first in the on block, but a push run always references a head commit and names the pusher as actor, neither of which appears in this run.
Why B is wrong: Tempting because workflow_dispatch needs no commit, but a manual run always records the person who clicked Run workflow as the actor, so an unnamed operator rules it out.
Why C is wrong: Tempting because that event also lacks a commit, but repository_dispatch is not in the on block and the stem states no external API call was recorded, so it cannot be the cause.
Why D is correct: A scheduled run fires from the cron timetable with no commit and no operator, and run history attributes it to the workflow itself, matching the empty actor and absent commit observed.