scylladb/.github/workflows/conflict_reminder.yaml

name: Notify PR Authors of Conflicts

permissions:
  issues: write
  pull-requests: write

on:
  push:
    branches:
      - 'master'
      - 'branch-*'
  schedule:
    - cron: '0 10 * * 1'  # Runs every Monday at 10:00am

jobs:
  notify_conflict_prs:
    runs-on: ubuntu-latest

    steps:
      - name: Notify PR Authors of Conflicts
        uses: actions/github-script@v7
        with:
          script: |
            console.log("Starting conflict reminder script...");
            // Print trigger event
            if (process.env.GITHUB_EVENT_NAME) {
              console.log(`Workflow triggered by: ${process.env.GITHUB_EVENT_NAME}`);
            } else {
              console.log("Could not determine workflow trigger event.");
            }
            const isPushEvent = process.env.GITHUB_EVENT_NAME === 'push';
            console.log(`isPushEvent: ${isPushEvent}`);
            const twoMonthsAgo = new Date();
            twoMonthsAgo.setMonth(twoMonthsAgo.getMonth() - 2);
            const prs = await github.paginate(github.rest.pulls.list, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              state: 'open',
              per_page: 100
            });
            console.log(`Fetched ${prs.length} open PRs`);
            const recentPrs = prs.filter(pr => new Date(pr.created_at) >= twoMonthsAgo);
            const validBaseBranches = ['master'];
            const branchPrefix = 'branch-';
            const oneWeekAgo = new Date();
            const conflictLabel = 'conflicts';
            oneWeekAgo.setDate(oneWeekAgo.getDate() - 7);
            console.log(`One week ago: ${oneWeekAgo.toISOString()}`);

            for (const pr of recentPrs) {
              console.log(`Checking PR #${pr.number} on base branch '${pr.base.ref}'`);
              const isBranchX = pr.base.ref.startsWith(branchPrefix);
              const isMaster = validBaseBranches.includes(pr.base.ref);
              if (!(isBranchX || isMaster)) {
                console.log(`PR #${pr.number} skipped: base branch is not 'master' or does not start with '${branchPrefix}'`);
                continue;
              }
              const updatedDate = new Date(pr.updated_at);
              console.log(`PR #${pr.number} last updated at: ${updatedDate.toISOString()}`);
              if (!isPushEvent && updatedDate >= oneWeekAgo) {
                console.log(`PR #${pr.number} skipped: updated within last week`);
                continue;
              }
              if (pr.assignee === null) {
                console.log(`PR #${pr.number} skipped: no assignee`);
                continue;
              }

              // Fetch PR details to check mergeability
              let { data: prDetails } = await github.rest.pulls.get({
                owner: context.repo.owner,
                repo: context.repo.repo,
                pull_number: pr.number,
              });
              console.log(`PR #${pr.number} mergeable: ${prDetails.mergeable}`);

              // Wait and re-fetch if mergeable is null
              if (prDetails.mergeable === null) {
                console.log(`PR #${pr.number} mergeable is null, waiting 2 seconds and retrying...`);
                await new Promise(resolve => setTimeout(resolve, 2000)); // wait 2 seconds
                prDetails = (await github.rest.pulls.get({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  pull_number: pr.number,
                })).data;
                console.log(`PR #${pr.number} mergeable after retry: ${prDetails.mergeable}`);
              }

              if (prDetails.mergeable === false) {
                const hasConflictLabel = pr.labels.some(label => label.name === conflictLabel);
                console.log(`PR #${pr.number} has conflict label: ${hasConflictLabel}`);

                // Fetch comments to check for existing notifications
                const comments = await github.paginate(github.rest.issues.listComments, {
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: pr.number,
                  per_page: 100,
                });
                
                // Find last notification comment from the bot
                const notificationPrefix = `@${pr.assignee.login}, this PR has merge conflicts with the base branch.`;
                const lastNotification = comments
                  .filter(c =>
                    c.user.type === "Bot" &&
                    c.body.startsWith(notificationPrefix)
                  )
                  .sort((a, b) => new Date(b.created_at) - new Date(a.created_at))[0];

                // Check if we should skip notification based on recent notification
                let shouldSkipNotification = false;
                if (lastNotification) {
                  const lastNotified = new Date(lastNotification.created_at);
                  if (lastNotified >= oneWeekAgo) {
                    console.log(`PR #${pr.number} skipped: last notification was less than 1 week ago`);
                    shouldSkipNotification = true;
                  }
                }

                // Additional check for push events on draft PRs with conflict labels
                if (
                  isPushEvent &&
                  pr.draft === true &&
                  hasConflictLabel &&
                  shouldSkipNotification
                ) {
                  continue;
                }

                if (!hasConflictLabel) {
                  await github.rest.issues.addLabels({
                    owner: context.repo.owner,
                    repo: context.repo.repo,
                    issue_number: pr.number,
                    labels: [conflictLabel],
                  });
                  console.log(`Added 'conflicts' label to PR #${pr.number}`);
                }
                
                const assignee = pr.assignee.login;
                if (assignee && !shouldSkipNotification) {
                  await github.rest.issues.createComment({
                    owner: context.repo.owner,
                    repo: context.repo.repo,
                    issue_number: pr.number,
                    body: `@${assignee}, this PR has merge conflicts with the base branch. Please resolve the conflicts so we can merge it.`,
                  });
                  console.log(`Notified @${assignee} for PR #${pr.number}`);
                }
              } else {
                console.log(`PR #${pr.number} is mergeable, no action needed.`);
              }
            }
            console.log(`Total PRs checked: ${prs.length}`);