Previously, the buildkite jobs wouldn't launch for PRs that were opened on forks, because the smooth-checkout plugin would not be able to find a valid refspec^1. This fixes this up for the most general cases, i.e., when a build is kicked off because a PR is opened or more commits are added on to the PR, and is not expected to work when builds are explicitly triggered (through the Web UI) for the HEAD commit.
Previously, the buildkite jobs wouldn't launch for PRs that were opened on forks, because the
smooth-checkoutplugin would not be able to find a valid refspec^1. This fixes this up for the most general cases, i.e., when a build is kicked off because a PR is opened or more commits are added on to the PR, and is not expected to work when builds are explicitly triggered (through the Web UI) for theHEADcommit.