--- buildbot: push to main
CI-RUN-CONTEXT: branch=main is_main=true is_pr=false pr_number=
--- buildbot: pull request
CI-RUN-CONTEXT: branch=refs/pull/42/merge is_main=false is_pr=true pr_number=42
--- buildbot: push to a feature branch
CI-RUN-CONTEXT: branch=feature/widget is_main=false is_pr=false pr_number=
--- buildbot: tag push carries no branch
CI-RUN-CONTEXT: branch= is_main=false is_pr=false pr_number=
--- nixbot: pull request against main resolves as a pull request
CI-RUN-CONTEXT: branch=refs/pull/42/merge is_main=false is_pr=true pr_number=42
--- nixbot: push to main resolves as main
CI-RUN-CONTEXT: branch=main is_main=true is_pr=false pr_number=
--- nixbot: push to a feature branch
CI-RUN-CONTEXT: branch=feature/widget is_main=false is_pr=false pr_number=