Trigger without cloning?

[jrobison-sb]

Is it possible to trigger a concourse pipeline using this resource without doing a get or a clone?

The use case is that we need to run some code once a month on a cron schedule, and also run that same code whenever a PR with a given label is merged. When a PR with a given label is merged, we don't need to clone that PR branch or interact with that PR at all. We only want the PR to trigger a job, but other than that we don't test anything in the PR or use the PR branch at all.

Currently we do it like this:

resource_types:
  - name: cron-resource
    type: docker-image
    source:
      repository: cftoolsmiths/cron-resource

  - name: pull-request
    type: docker-image
    source:
      repository: cfcommunity/github-pr-resource
      tag: "0.25.2"

resources:

  - name: devops
    type: git
    icon: github
    source:
      branch: master
      uri: git@github.com:company/devops.git
      private_key: ((github_deploy_private_key))

  - name: merged-offboarding-pull-request
    type: pull-request
    check_every: 2m
    source:
      repository: company/devops
      access_token: ((github_api_token))
      paths:
        - some_file_from_the_latest_pr.txt
      base_branch: master
      states:
        - MERGED
      labels:
        - STAFF-OFFBOARDING

  - name: monthly
    type: cron-resource
    icon: calendar
    source:
      expression: "0 13 01 * *" # 1PM on the first day of the month
      location: "America/New_York"

jobs:
  - name: some-job
    plan:
    - get: devops
    # Trigger the job monthly
    - get: monthly
      trigger: true
    # OR when an offboarding PR is merged
    - get: merged-offboarding-pull-request
      trigger: true
    - task: some-job
      config:
        platform: linux
        image_resource:
          type: docker-image
          source:
            repository: ubuntu
            tag: 24.04
 
        inputs:
          - name: devops # Notice that there is no input for the PR branch, we don't use the PR branch at all other than as a trigger

        run:
          dir: devops
          path: ./some_script.sh

The above does work most of the time. But currently we found ourselves in a state where the get step of the PR fails because of a merge conflict:

Initialized empty Git repository in /tmp/build/get/.git/
Switched to a new branch 'master'
Auto-merging some_file_from_the_latest_pr.txt
CONFLICT (content): Merge conflict in some_file_from_the_latest_pr.txt
Automatic merge failed; fix conflicts and then commit the result.
2025/06/05 14:09:25 get failed: merge failed: exit status 1

I can probably work around this by pushing a new PR which doesn't conflict with master, but since our use case doesn't use the PR branch at all, is it possible to use a PR as a trigger without get'ing or cloning the PR branch at all?

Thanks.