tag-merge-conflicts.yml

name: Tag Merge Conflicts
on:
  push:
    branches: ['develop']
  pull_request:
    branches: ['develop']
jobs:
  merge-conflicts:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
      - uses: actions/github-script@v6
        with:
          script: |
            const pullRequests = (await github.rest.pulls.list({
                ...context.repo
            })).data

            const addMergeConflictTag = async (pullRequests) => {
              const promises = pullRequests.map(pr => {
                  const { number } = pr
                  return github.rest.pulls.get({
                      ...context.repo,
                      pull_number: number
                  })
              })

              const prs = await Promise.allSettled(promises)
              const prsAwaitingCheck = []

              prs.forEach(pr => {
                  const data = pr.value.data
                  if (data.mergeable === false) {
                      github.rest.issues.addLabels({
                          ...context.repo,
                          issue_number: data.number,
                          labels: ["merge conflict"]
                      })
                  } else if (data.mergeable === true 
                      && data.labels.some(label => label.name === "merge conflict")) {
                          github.rest.issues.removeLabel({
                              ...context.repo,
                              issue_number: data.number,
                              name: "merge conflict"
                          })
                  } else if (data.mergeable === null) {
                    prsAwaitingCheck.push({...data})
                  }
              })

              if (prsAwaitingCheck.length) {
                console.log("Some PRs are still waiting to calculate status...")
                await new Promise(resolve => setTimeout(resolve, 5000))
                addMergeConflictTag(prsAwaitingCheck)
              }

            }

            await addMergeConflictTag(pullRequests)