fix: handle unavailable Jenkins commit build data

Jenkins can retain a successful PR build result while returning null
for its nested commit build. Accessing that build's subBuilds crashes
git node metadata and aborts commit queue filtering.

Preserve the recorded result when child build data is unavailable.
Report unavailable details for non-successful builds without throwing.

Refs: https://github.com/nodejs/node/actions/runs/34948903953/job/104314954048
Signed-off-by: Filip Skokan <panva.ip@gmail.com>
Assisted-by: Codex

Author: panva

lib/ci/build-types/pr_build.js

@@ -1,4 +1,5 @@
 import { PR_TREE } from '../jenkins_constants.js';
+import { statusType } from '../ci_utils.js';
 import CIFailureParser from '../ci_failure_parser.js';
 import { TestBuild } from './test_build.js';
 import { CommitBuild } from './commit_build.js';
@@ -69,7 +70,7 @@ export class PRBuild extends TestBuild {
 
     // Get result from the sub build
     // assert.strictEqual(commitBuild.jobName, 'node-test-commit');
-    const allBuilds = commitBuild.build.subBuilds;
+    const allBuilds = commitBuild.build?.subBuilds;
     // TODO: fetch result, builtOn, timestamp in the commit build's own data
     // ..or maybe they do not worth an additional API call?
     // Note that we have to pass the actions down to detect resume builds.
@@ -78,6 +79,15 @@ export class PRBuild extends TestBuild {
     };
     const commitBuildId = commitBuild.buildNumber;
     this.commitBuild = new CommitBuild(cli, request, commitBuildId, this.skipMoreThan);
+    // Jenkins can retain the result after the nested build is no longer available.
+    if (!commitBuild.build) {
+      this.commitBuild.setBuildData(buildData);
+      this.failures = result === statusType.SUCCESS
+        ? []
+        : [new NCUFailure({ url: this.commitBuild.jobUrl }, 'Build data is unavailable')];
+      this.commitBuild.failures = this.failures;
+      return { result, builds: this.builds, failures: this.failures };
+    }
     const { builds, failures } = await this.commitBuild.getResults(buildData);
 
     // Set up aliases for display

test/unit/ci_result_parser.test.js

@@ -94,6 +94,42 @@ describe('Jenkins', () => {
     assert.strictEqual(markdown, expected);
   });
 
+  for (const result of ['SUCCESS', 'FAILURE', null]) {
+    it(`should handle unavailable commit build data with result ${result}`, async(t) => {
+      const data = fixtures.readJSON(
+        'jenkins', 'success', 'node-test-pull-request-15237.json'
+      );
+      data.result = result;
+      data.subBuilds[0].result = result;
+      data.subBuilds[0].build = null;
+
+      const cli = new TestCLI();
+      const prBuild = new PRBuild(cli, {}, 15237);
+      t.mock.method(prBuild, 'getBuildData', async() => data);
+      const results = await prBuild.getResults();
+
+      assert.strictEqual(results.result, result);
+      assert.deepStrictEqual(results.builds, {
+        failed: [], aborted: [], pending: [], unstable: []
+      });
+      assert.strictEqual(prBuild.commitBuild.result, result);
+      assert.deepStrictEqual(prBuild.commitBuild.failures, prBuild.failures);
+      if (result === 'SUCCESS') {
+        assert.deepStrictEqual(results.failures, []);
+        assert.deepStrictEqual(prBuild.formatAsJson(), []);
+        assert.strictEqual(prBuild.formatAsMarkdown(), `Job ${prBuild.jobUrl} is green.`);
+      } else {
+        assert.strictEqual(results.failures.length, 1);
+        assert.strictEqual(results.failures[0].type, 'NCU_FAILURE');
+        assert.strictEqual(results.failures[0].url, prBuild.commitBuild.jobUrl);
+        assert.strictEqual(results.failures[0].reason, 'Build data is unavailable');
+        assert.match(prBuild.formatAsMarkdown(), /Build data is unavailable/);
+        assert.strictEqual(prBuild.formatAsJson()[0].reason, 'Build data is unavailable');
+      }
+      prBuild.display();
+    });
+  }
+
   it('should handle node-test-commit trigger failure', async() => {
     tmpdir.refresh();
     const prefix = ['jenkins', 'trigger-failure'];

test/unit/pr_checker.test.js

@@ -1386,6 +1386,38 @@ describe('PRChecker', () => {
       });
     });
 
+    for (const result of ['SUCCESS', 'FAILURE', null]) {
+      it(`should check CI with unavailable commit build data and result ${result}`, async() => {
+        const jenkins = structuredClone(jenkinsCI['success/node-test-pull-request-15237']);
+        jenkins.result = result;
+        jenkins.subBuilds[0].result = result;
+        jenkins.subBuilds[0].build = null;
+        const data = {
+          pr: firstTimerPR,
+          comments: commentsWithSuccessCI,
+          reviews: approvingReviews,
+          commits: githubCI['check-suite-success'],
+          getThread() {
+            return PRData.prototype.getThread.call(this);
+          }
+        };
+        const checker = new PRChecker(new TestCLI(), data, {
+          async json(url) {
+            assert(url.startsWith(jenkins.url));
+            return jenkins;
+          }
+        }, argv);
+
+        assert.strictEqual(Boolean(await checker.checkCI()), result === 'SUCCESS');
+        assert.deepStrictEqual(checker.reasons.map(({ code }) => code),
+          result === 'SUCCESS'
+            ? []
+            : [result === null
+                ? PR_CHECK_REASON_CODES.PENDING_JENKINS_CI
+                : PR_CHECK_REASON_CODES.FAILED_JENKINS_CI]);
+      });
+    }
+
     it('should error if failed Jenkins CI', async() => {
       const cli = new TestCLI();