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milkshakeukmilkshakeuk
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build: add Dependabot auto-merge workflow
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‎.github/workflows/dependabot-auto-approve.yml‎

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Original file line numberDiff line numberDiff line change
@@ -6,6 +6,7 @@ on:
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branches:
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- main
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- dependabot-merge
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permissions:
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pull-requests: write
@@ -16,7 +17,8 @@ jobs:
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runs-on: ubuntu-latest
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# Check for success, an associated PR, and the correct target branch
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if: |
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github.event.pull_request.base.ref == 'main' &&
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(github.event.pull_request.base.ref == 'main' ||
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github.event.pull_request.base.ref == 'dependabot-merge') &&
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github.event.pull_request.user.login == 'dependabot[bot]'
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steps:

‎.github/workflows/dependabot-auto-merge.yml‎

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name: Dependabot Auto Merge
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on:
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check_suite:
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types: [completed]
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permissions:
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contents: write
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pull-requests: write
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checks: read
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jobs:
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final-merge:
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runs-on: ubuntu-latest
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if: |
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github.actor == 'dependabot[bot]' &&
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github.event.check_suite.pull_requests[0].base.ref == 'dependabot-merge'
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steps:
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- name: Checkout
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uses: actions/checkout@v6
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- name: Attempt Merge
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id: attempt-merge
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uses: actions/github-script@v8
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with:
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github-token: ${{ secrets.GITHUB_TOKEN }}
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script: |
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const { owner, repo } = context.repo;
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const checkSuite = context.payload.check_suite;
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// 1. Identify the PR number
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if (!checkSuite.pull_requests || checkSuite.pull_requests.length === 0) {
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core.setOutput('result', 'failed');
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core.setFailed("No PR associated with this check suite.");
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return;
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}
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const prNumber = checkSuite.pull_requests[0].number;
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core.info(`Processing PR #${prNumber}`);
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core.setOutput('pr_number', prNumber);
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core.setOutput('result', 'failed') // Default to failed unless we succeed later
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// Fetch full PR details
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const { data: pr } = await github.rest.pulls.get({
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owner,
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repo,
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pull_number: prNumber,
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});
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// 2. Polling Loop for Checks
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// We wait until all OTHER checks are completed.
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const sleep = (ms) => new Promise(r => setTimeout(r, ms));
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const MAX_WAIT_MS = 10 * 60 * 1000; // 10 minutes timeout
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const RETRY_MS = 10000; // Check every 10 seconds
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const startTime = Date.now();
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let allChecks = [];
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core.info("Verifying check status...");
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while (true) {
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// Fetch latest checks for the commit
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const { data: checks } = await github.rest.checks.listForRef({
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owner,
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repo,
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ref: pr.head.sha,
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filter: 'latest'
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});
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allChecks = checks.check_runs;
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// CRITICAL: Exclude THIS job from the check list.
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// 'context.job' is the job ID from YAML ('final-merge').
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// We filter out any check run with this name.
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const otherChecks = allChecks.filter(run => run.name !== context.job);
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const pending = otherChecks.filter(run => run.status !== 'completed');
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if (pending.length === 0) {
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core.info("All other checks have completed.");
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break;
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}
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if (Date.now() - startTime > MAX_WAIT_MS) {
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core.setOutput('result', 'failed')
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core.setFailed(`Timeout waiting for checks: ${pending.map(c => c.name).join(', ')}`);
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pending.forEach(c => core.info(` - ${c.name}: ${c.status} / ${c.conclusion}`));
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return;
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}
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core.info(`Waiting for ${pending.length} checks to complete:`);
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pending.forEach(c => core.info(` - ${c.name}: ${c.status} / ${c.conclusion}`));
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await sleep(RETRY_MS);
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}
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// 3. Validate Conclusions
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// Now that everything is completed, check if they passed.
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const otherChecks = allChecks.filter(run => run.name !== context.job);
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// Fail if any check is incomplete or concluded with failure/cancelled
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// Note: We accept 'neutral' and 'skipped' as passing
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const badChecks = otherChecks.filter(run =>
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run.status !== 'completed' ||
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!['success', 'skipped', 'neutral'].includes(run.conclusion)
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);
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if (badChecks.length > 0) {
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core.setOutput('result', 'failed');
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core.setFailed(`Not all checks are green yet. Found ${badChecks.length} incomplete or failed checks:`);
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badChecks.forEach(c => core.info(` - ${c.name}: ${c.status} / ${c.conclusion}`));
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return;
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}
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// 4. Check for the "auto-approved" label
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const hasLabel = pr.labels.some(l => l.name === "auto-approved");
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if (!hasLabel) {
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core.setOutput('result', 'failed');
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core.setFailed("PR does not have 'auto-approved' label. Skipping.");
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return;
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}
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// 5. Check if PR is strictly up-to-date (Fast Forward possible)
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const prBaseSha = pr.base.sha;
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const targetBranch = pr.base.ref;
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// Get current SHA of the target branch from remote
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const { data: refData } = await github.rest.git.getRef({
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owner,
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repo,
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ref: `heads/${targetBranch}`
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});
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const currentBaseSha = refData.object.sha;
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if (prBaseSha !== currentBaseSha) {
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core.setOutput('result', 're-triggered');
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core.setFailed(`PR is behind ${targetBranch}. Cannot fast-forward merge.`);
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core.info("Asking Dependabot to recreate PR...");
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await github.rest.issues.createComment({
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owner,
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repo,
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issue_number: prNumber,
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body: "@dependabot recreate"
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});
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return;
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}
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// 6. Merge
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core.info("PR is clean, labelled, and strictly up-to-date. Merging...");
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try {
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await github.rest.pulls.merge({
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owner,
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repo,
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pull_number: prNumber,
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merge_method: 'rebase'
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});
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core.info("Merge request sent successfully.");
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core.setOutput('result', 'success');
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} catch (error) {
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core.setOutput('result', 'failed');
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core.setFailed(`Merge failed: ${error.message}`);
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// We do not fail the workflow here to avoid noise, just log it.
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}
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- name: Comment automerge results
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uses: actions/github-script@v8
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if: always() && steps.attempt-merge.outputs.result != 're-triggered'
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env:
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MERGE_RESULT: ${{ steps.attempt-merge.outputs.result }}
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PR_NUMBER: ${{ steps.attempt-merge.outputs.pr_number }}
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with:
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script: |
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const { owner, repo } = context.repo;
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// Get PR number from step output (context.payload.pull_request is null in check_suite events)
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const prNumber = parseInt(process.env.PR_NUMBER);
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if (!prNumber || isNaN(prNumber)) {
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core.info('No valid PR number found; skipping comment.');
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return;
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}
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const jobSummaryUrl = `https://github.com/${owner}/${repo}/actions/runs/${context.runId}`;
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const prHead = context.payload.pull_request?.head;
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const headCommitSha = prHead?.sha ?? process.env.GITHUB_SHA ?? '';
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const shortSha = headCommitSha ? headCommitSha.slice(0, 7) : 'unknown';
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const runResult = process.env.MERGE_RESULT?.toLowerCase() ?? '';
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const isFailure = runResult === 'failed';
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const marker = '<!-- dependabot-merge-comment -->';
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const heading = isFailure
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? '## ⚠️ Auto Merge Failed'
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: '## ✅ Auto Merge Succeeded';
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const narration = `Please check the [workflow run↗️](${jobSummaryUrl}) for details.`;
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const bodySections = [
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heading,
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narration
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];
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const existingComments = await github.paginate(
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github.rest.issues.listComments,
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{
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owner,
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repo,
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issue_number: prNumber,
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per_page: 100,
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},
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);
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const previous = existingComments.find((comment) =>
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comment.body?.includes(marker),
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);
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if(previous) {
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bodySections.push(':recycle: This comment has been updated with latest results.');
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}
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const body = `${marker}\n${bodySections.join('\n\n')}\n${marker}`;
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if (previous) {
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core.info(`Updating existing auto merge comment (${previous.id}).`);
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await github.rest.issues.updateComment({
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owner,
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repo,
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comment_id: previous.id,
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body,
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});
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} else {
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core.info('Creating new auto merge comment.');
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await github.rest.issues.createComment({
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owner,
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repo,
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issue_number: prNumber,
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body,
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});
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}

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