fix: do not reuse branch if cache fingerprint doesn't match (renovatebot#36616)

Author: rarkins

lib/workers/repository/process/write.spec.ts

@@ -15,7 +15,7 @@ import type { BranchConfig, BranchUpgradeConfig } from '../../types';
 import * as _branchWorker from '../update/branch';
 import * as _limits from './limits';
 import {
-  canSkipBranchUpdateCheck,
+  compareCacheFingerprint,
   generateCommitFingerprintConfig,
   syncBranchState,
   writeUpdates,
@@ -358,7 +358,9 @@ describe('workers/repository/process/write', () => {
         branchName: 'new/some-branch',
         sha: '111',
       };
-      expect(canSkipBranchUpdateCheck(branchCache, '222')).toBe(false);
+      expect(compareCacheFingerprint(branchCache, '222')).toBe(
+        'no-fingerprint',
+      );
     });
 
     it('returns false when fingerprints are not same', () => {
@@ -368,7 +370,7 @@ describe('workers/repository/process/write', () => {
         sha: '111',
         commitFingerprint: '211',
       };
-      expect(canSkipBranchUpdateCheck(branchCache, '222')).toBe(false);
+      expect(compareCacheFingerprint(branchCache, '222')).toBe('no-match');
     });
 
     it('returns true', () => {
@@ -378,7 +380,7 @@ describe('workers/repository/process/write', () => {
         sha: '111',
         commitFingerprint: '222',
       };
-      expect(canSkipBranchUpdateCheck(branchCache, '222')).toBe(true);
+      expect(compareCacheFingerprint(branchCache, '222')).toBe('matched');
     });
   });
 

lib/workers/repository/process/write.ts

@@ -8,7 +8,11 @@ import type { BranchCache } from '../../../util/cache/repository/types';
 import { fingerprint } from '../../../util/fingerprint';
 import { setBranchNewCommit } from '../../../util/git/set-branch-commit';
 import { incCountValue, setCount } from '../../global/limits';
-import type { BranchConfig, UpgradeFingerprintConfig } from '../../types';
+import type {
+  BranchConfig,
+  CacheFingerprintMatchResult,
+  UpgradeFingerprintConfig,
+} from '../../types';
 import { processBranch } from '../update/branch';
 import { upgradeFingerprintFields } from './fingerprint-fields';
 import {
@@ -33,22 +37,22 @@ export function generateCommitFingerprintConfig(
   return res;
 }
 
-export function canSkipBranchUpdateCheck(
+export function compareCacheFingerprint(
   branchState: BranchCache,
   commitFingerprint: string,
-): boolean {
+): CacheFingerprintMatchResult {
   if (!branchState.commitFingerprint) {
     logger.trace('branch.isUpToDate(): no fingerprint');
-    return false;
+    return 'no-fingerprint';
   }
 
   if (commitFingerprint !== branchState.commitFingerprint) {
     logger.debug('branch.isUpToDate(): needs recalculation');
-    return false;
+    return 'no-match';
   }
 
   logger.debug('branch.isUpToDate(): using cached result "true"');
-  return true;
+  return 'matched';
 }
 
 export async function syncBranchState(
@@ -156,7 +160,7 @@ export async function writeUpdates(
       commitFingerprintConfig: generateCommitFingerprintConfig(branch),
       managers,
     });
-    branch.skipBranchUpdate = canSkipBranchUpdateCheck(
+    branch.cacheFingerprintMatch = compareCacheFingerprint(
       branchState,
       commitFingerprint,
     );

lib/workers/repository/update/branch/index.spec.ts

@@ -32,7 +32,11 @@ import * as _mergeConfidence from '../../../../util/merge-confidence';
 import * as _sanitize from '../../../../util/sanitize';
 import type { Timestamp } from '../../../../util/timestamp';
 import * as _limits from '../../../global/limits';
-import type { BranchConfig, BranchUpgradeConfig } from '../../../types';
+import type {
+  BranchConfig,
+  BranchUpgradeConfig,
+  CacheFingerprintMatchResult,
+} from '../../../types';
 import type { ResultWithPr } from '../pr';
 import * as _prWorker from '../pr';
 import * as _prAutomerge from '../pr/automerge';
@@ -897,6 +901,38 @@ describe('workers/repository/update/branch/index', () => {
       expect(prWorker.ensurePr).toHaveBeenCalledTimes(0);
     });
 
+    it('updates branch when no fingerprint match', async () => {
+      expect.assertions(3);
+      getUpdated.getUpdatedPackageFiles.mockResolvedValueOnce(
+        partial<PackageFilesResult>({
+          updatedPackageFiles: [partial<FileChange>()],
+        }),
+      );
+      npmPostExtract.getAdditionalFiles.mockResolvedValueOnce({
+        artifactErrors: [],
+        updatedArtifacts: [partial<FileChange>()],
+      });
+      const inconfig = {
+        ...config,
+        ignoreTests: true,
+        prCreation: 'not-pending',
+        commitBody: '[skip-ci]',
+        fetchChangeLogs: 'branch',
+        cacheFingerprintMatch: 'no-match',
+      } satisfies BranchConfig;
+      scm.getBranchCommit.mockResolvedValue('123test' as LongCommitSha); //TODO:not needed?
+      expect(await branchWorker.processBranch(inconfig)).toEqual({
+        branchExists: true,
+        updatesVerified: true,
+        prNo: undefined,
+        result: 'pending',
+        commitSha: '123test',
+      });
+
+      expect(automerge.tryBranchAutomerge).toHaveBeenCalledTimes(0);
+      expect(prWorker.ensurePr).toHaveBeenCalledTimes(0);
+    });
+
     it('ensures PR and comments notice', async () => {
       getUpdated.getUpdatedPackageFiles.mockResolvedValueOnce(
         partial<PackageFilesResult>({
@@ -1226,7 +1262,7 @@ describe('workers/repository/update/branch/index', () => {
       await branchWorker.processBranch({
         ...config,
         baseBranch: 'new_base',
-        skipBranchUpdate: true,
+        cacheFingerprintMatch: 'matched',
       });
       expect(logger.debug).toHaveBeenCalledWith(
         'Base branch changed by user, rebasing the branch onto new base',
@@ -1480,7 +1516,7 @@ describe('workers/repository/update/branch/index', () => {
         branchPrefixOld: 'old/',
         commitFingerprint: '111',
         reuseExistingBranch: true,
-        skipBranchUpdate: true,
+        cacheFingerprintMatch: 'matched' as CacheFingerprintMatchResult,
       };
       expect(await branchWorker.processBranch(inconfig)).toEqual({
         branchExists: true,
@@ -2500,7 +2536,7 @@ describe('workers/repository/update/branch/index', () => {
         }),
       );
       config.reuseExistingBranch = true;
-      config.skipBranchUpdate = true;
+      config.cacheFingerprintMatch = 'matched';
       const inconfig = {
         ...config,
         branchName: 'new/some-branch',

lib/workers/repository/update/branch/index.ts

@@ -475,12 +475,21 @@ export async function processBranch(
         'Base branch changed by user, rebasing the branch onto new base',
       );
       config.reuseExistingBranch = false;
+    } else if (config.cacheFingerprintMatch === 'no-match') {
+      logger.debug(
+        'Cache fingerprint does not match, cannot reuse existing branch',
+      );
+      config.reuseExistingBranch = false;
     } else {
       config = await shouldReuseExistingBranch(config);
     }
     // TODO: types (#22198)
     logger.debug(`Using reuseExistingBranch: ${config.reuseExistingBranch!}`);
-    if (!(config.reuseExistingBranch && config.skipBranchUpdate)) {
+    if (
+      !(
+        config.reuseExistingBranch && config.cacheFingerprintMatch === 'matched'
+      )
+    ) {
       await scm.checkoutBranch(config.baseBranch);
       const res = await getUpdatedPackageFiles(config);
       // istanbul ignore if

lib/workers/types.ts

@@ -113,6 +113,11 @@ export type BranchResult =
   | 'rebase'
   | 'update-not-scheduled';
 
+export type CacheFingerprintMatchResult =
+  | 'matched'
+  | 'no-match'
+  | 'no-fingerprint';
+
 export interface BranchConfig
   extends BranchUpgradeConfig,
     LegacyAdminConfig,
@@ -135,7 +140,7 @@ export interface BranchConfig
   stopUpdating?: boolean;
   isConflicted?: boolean;
   commitFingerprint?: string;
-  skipBranchUpdate?: boolean;
+  cacheFingerprintMatch?: CacheFingerprintMatchResult;
 }
 
 export interface BranchMetadata {