Get Pull Request ID when build is triggered by push

Question & Answer
1

I want to get the pull request ID when a workflow is triggered due to a push, not just Pull Request..

  1. The available environment variable, BITRISE_PULL_REQUEST is empty.
  2. I thought, I could try extract the ID after the “/pull-requests/“ part of the entire PR url, so I tried to access the BITRISEIO_PULL_REQUEST_REPOSITORY_URL, but it also came up empty.

Can anyone help me with some resource to get the pull request ID when build is triggered by “push“.