nodejs · aduh95 · Mar 23, 2026 · Mar 16, 2026
diff --git a/bin/ncu-ci.js b/bin/ncu-ci.js
@@ -119,6 +119,11 @@ const args = yargs(hideBin(process.argv))
                     'If not provided, the command will use the SHA of the last approved commit.',
           type: 'string'
         })
+        .option('check-for-duplicates', {
+          describe: 'When set, NCU will query Jenkins recent builds to ensure ' +
+                    'there is not an existing job for the same commit.',
+          type: 'boolean'
+        })
         .option('owner', {
           default: '',
           describe: 'GitHub repository owner'
@@ -298,7 +303,10 @@ class RunPRJobCommand {
       this.cli.setExitCode(1);
       return;
     }
-    const jobRunner = new RunPRJob(cli, request, owner, repo, prid, this.argv.certifySafe);
+    const { certifySafe, checkForDuplicates } = this.argv;
+    const jobRunner = new RunPRJob(
+      cli, request, owner, repo, prid,
+      certifySafe, checkForDuplicates);
     if (!(await jobRunner.start())) {
       this.cli.setExitCode(1);
       process.exitCode = 1;

diff --git a/lib/ci/build-types/pr_build.js b/lib/ci/build-types/pr_build.js
@@ -15,9 +15,8 @@ const {
 } = CIFailureParser;
 
 export class PRBuild extends TestBuild {
-  constructor(cli, request, id, skipMoreThan) {
+  constructor(cli, request, id, skipMoreThan, tree = PR_TREE) {
     const path = `job/node-test-pull-request/${id}/`;
-    const tree = PR_TREE;
     super(cli, request, path, tree);
     this.skipMoreThan = skipMoreThan;
     this.commitBuild = null;

diff --git a/lib/ci/run_ci.js b/lib/ci/run_ci.js
@@ -1,13 +1,15 @@
 import { FormData } from 'undici';
 
 import {
+  JobParser,
   CI_DOMAIN,
   CI_TYPES,
   CI_TYPES_KEYS
 } from './ci_type_parser.js';
 import PRData from '../pr_data.js';
 import { debuglog } from '../verbosity.js';
 import PRChecker from '../pr_checker.js';
+import { PRBuild } from './build-types/pr_build.js';
 
 export const CI_CRUMB_URL = `https://${CI_DOMAIN}/crumbIssuer/api/json`;
 const CI_PR_NAME = CI_TYPES.get(CI_TYPES_KEYS.PR).jobName;
@@ -17,7 +19,7 @@ const CI_V8_NAME = CI_TYPES.get(CI_TYPES_KEYS.V8).jobName;
 export const CI_V8_URL = `https://${CI_DOMAIN}/job/${CI_V8_NAME}/build`;
 
 export class RunPRJob {
-  constructor(cli, request, owner, repo, prid, certifySafe) {
+  constructor(cli, request, owner, repo, prid, certifySafe, checkForDuplicates) {
     this.cli = cli;
     this.request = request;
     this.owner = owner;
@@ -29,6 +31,7 @@ export class RunPRJob {
       Promise.all([this.prData.getReviews(), this.prData.getCommits()]).then(() =>
         (this.certifySafe = new PRChecker(cli, this.prData, request, {}).getApprovedTipOfHead())
       );
+    this.checkForDuplicates = checkForDuplicates;
   }
 
   async getCrumb() {
@@ -70,7 +73,7 @@ export class RunPRJob {
   }
 
   async start() {
-    const { cli, certifySafe } = this;
+    const { cli, request, certifySafe, checkForDuplicates } = this;
 
     if (!(await certifySafe)) {
       cli.error('Refusing to run CI on potentially unsafe PR');
@@ -87,9 +90,25 @@ export class RunPRJob {
     }
     cli.stopSpinner('Jenkins credentials valid');
 
+    if (checkForDuplicates) {
+      await this.prData.getComments();
+      const { jobid, link } = new JobParser(this.prData.comments).parse().get('PR') ?? {};
+      const { actions } = jobid
+        ? (await new PRBuild(cli, request, jobid, undefined, 'actions[parameters[name,value]]')
+            .getBuildData())
+        : {};
+      const { parameters } = actions?.find(a => 'parameters' in a) ?? {};
+      if (parameters?.find(c => c.name === 'COMMIT_SHA_CHECK')?.value === certifySafe) {
+        cli.info('Existing CI run found: ' + link);
+        cli.error('Refusing to start a potentially duplicate CI job. Use the ' +
+          '"Resume build" button in the Jenkins UI, or start a new CI manually.');
+        return false;
+      }
+    }
+
     try {
       cli.startSpinner('Starting PR CI job');
-      const response = await this.request.fetch(CI_PR_URL, {
+      const response = await request.fetch(CI_PR_URL, {
         method: 'POST',
         headers: {
           'Jenkins-Crumb': crumb
@@ -106,10 +125,10 @@ export class RunPRJob {
 
       // check if the job need a v8 build and trigger it
       await this.prData.getPR();
-      const labels = this.prData.pr.labels;
-      if (labels.nodes.map(i => i.name).includes('v8 engine')) {
+      const { labels } = this.prData.pr;
+      if (labels?.nodes.some(i => i.name === 'v8 engine')) {
         cli.startSpinner('Starting V8 CI job');
-        const response = await this.request.fetch(CI_V8_URL, {
+        const response = await request.fetch(CI_V8_URL, {
           method: 'POST',
           headers: {
             'Jenkins-Crumb': crumb

diff --git a/test/unit/ci_start.test.js b/test/unit/ci_start.test.js
@@ -1,4 +1,4 @@
-import { describe, it, before, afterEach } from 'node:test';
+import { describe, it, before, afterEach, beforeEach } from 'node:test';
 import assert from 'assert';
 
 import * as sinon from 'sinon';
@@ -13,6 +13,9 @@ import {
 import PRChecker from '../../lib/pr_checker.js';
 
 import TestCLI from '../fixtures/test_cli.js';
+import { PRBuild } from '../../lib/ci/build-types/pr_build.js';
+import { JobParser } from '../../lib/ci/ci_type_parser.js';
+import PRData from '../../lib/pr_data.js';
 
 describe('Jenkins', () => {
   const owner = 'nodejs';
@@ -199,4 +202,129 @@ describe('Jenkins', () => {
       });
     }
   });
+
+  describe('--check-for-duplicates', { concurrency: false }, () => {
+    beforeEach(() => {
+      sinon.replace(PRData.prototype, 'getComments', sinon.fake.resolves());
+      sinon.replace(PRData.prototype, 'getPR', sinon.fake.resolves());
+      sinon.replace(JobParser.prototype, 'parse',
+        sinon.fake.returns(new Map().set('PR', { jobid: 123456 })));
+    });
+    afterEach(() => {
+      sinon.restore();
+    });
+
+    const getParameters = (commitHash) =>
+      [
+        {
+          _class: 'hudson.model.BooleanParameterValue',
+          name: 'CERTIFY_SAFE',
+          value: true
+        },
+        {
+          _class: 'hudson.model.StringParameterValue',
+          name: 'COMMIT_SHA_CHECK',
+          value: commitHash
+        },
+        {
+          _class: 'hudson.model.StringParameterValue',
+          name: 'TARGET_GITHUB_ORG',
+          value: 'nodejs'
+        },
+        {
+          _class: 'hudson.model.StringParameterValue',
+          name: 'TARGET_REPO_NAME',
+          value: 'node'
+        },
+        {
+          _class: 'hudson.model.StringParameterValue',
+          name: 'PR_ID',
+          value: prid
+        },
+        {
+          _class: 'hudson.model.StringParameterValue',
+          name: 'REBASE_ONTO',
+          value: '<pr base branch>'
+        },
+        {
+          _class: 'com.wangyin.parameter.WHideParameterValue',
+          name: 'DESCRIPTION_SETTER_DESCRIPTION',
+          value: ''
+        }
+      ];
+    const mockJenkinsResponse = parameters => ({
+      _class: 'com.tikal.jenkins.plugins.multijob.MultiJobBuild',
+      actions: [
+        { _class: 'hudson.model.CauseAction' },
+        { _class: 'hudson.model.ParametersAction', parameters },
+        { _class: 'hudson.model.ParametersAction', parameters },
+        { _class: 'hudson.model.ParametersAction', parameters },
+        {},
+        { _class: 'hudson.model.CauseAction' },
+        {},
+        {},
+        {},
+        {},
+        { _class: 'hudson.plugins.git.util.BuildData' },
+        {},
+        {},
+        {},
+        {},
+        { _class: 'hudson.model.ParametersAction', parameters },
+        {
+          _class: 'hudson.plugins.parameterizedtrigger.BuildInfoExporterAction'
+        },
+        {
+          _class: 'com.tikal.jenkins.plugins.multijob.MultiJobTestResults'
+        },
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {},
+        {
+          _class: 'org.jenkinsci.plugins.displayurlapi.actions.RunDisplayAction'
+        }
+      ]
+    });
+
+    it('should return false if already started', async() => {
+      const cli = new TestCLI();
+      sinon.replace(PRBuild.prototype, 'getBuildData',
+        sinon.fake.resolves(mockJenkinsResponse(getParameters('deadbeef'))));
+
+      const jobRunner = new RunPRJob(cli, {}, owner, repo, prid, 'deadbeef', true);
+      assert.strictEqual(await jobRunner.start(), false);
+    });
+    it('should return true when last CI is on a different commit', async() => {
+      const cli = new TestCLI();
+      sinon.replace(PRBuild.prototype, 'getBuildData',
+        sinon.fake.resolves(mockJenkinsResponse(getParameters('123456789abcdef'))));
+
+      const request = {
+        gql: sinon.stub().returns({
+          repository: {
+            pullRequest: {
+              labels: {
+                nodes: []
+              }
+            }
+          }
+        }),
+        fetch: sinon.stub()
+          .callsFake((url, { method, headers, body }) => {
+            assert.strictEqual(url, CI_PR_URL);
+            assert.strictEqual(method, 'POST');
+            assert.deepStrictEqual(headers, { 'Jenkins-Crumb': crumb });
+            return Promise.resolve({ status: 201 });
+          }),
+        json: sinon.stub().withArgs(CI_CRUMB_URL).resolves({ crumb })
+      };
+      const jobRunner = new RunPRJob(cli, request, owner, repo, prid, 'deadbeef', true);
+      assert.strictEqual(await jobRunner.start(), true);
+    });
+  });
 });