[kbn/optimizer] include bootstrap cache key in optimizer cache key (e…

…lastic#58176)

* [kbn/optimizer] include bootstrap cache key in optimizer cache key

* remove cache buster

* update cache keys tests

* move mocks

packages/kbn-optimizer/src/index.ts

@@ -17,7 +17,6 @@
  * under the License.
  */
 
-// cache buster - https://github.com/elastic/kibana/issues/58077 - 1
 export { OptimizerConfig } from './optimizer';
 export * from './run_optimizer';
 export * from './log_optimizer_state';

packages/kbn-optimizer/src/optimizer/cache_keys.test.ts

@@ -17,14 +17,35 @@
  * under the License.
  */
 
+import Path from 'path';
+
 import jestDiff from 'jest-diff';
 import { REPO_ROOT, createAbsolutePathSerializer } from '@kbn/dev-utils';
 
 import { reformatJestDiff, getOptimizerCacheKey, diffCacheKey } from './cache_keys';
 import { OptimizerConfig } from './optimizer_config';
 
-jest.mock('./get_changes.ts');
+jest.mock('./get_changes.ts', () => ({
+  getChanges: async () =>
+    new Map([
+      ['/foo/bar/a', 'modified'],
+      ['/foo/bar/b', 'modified'],
+      ['/foo/bar/c', 'deleted'],
+    ]),
+}));
+
+jest.mock('./get_mtimes.ts', () => ({
+  getMtimes: async (paths: string[]) => new Map(paths.map(path => [path, 12345])),
+}));
+
 jest.mock('execa');
+
+jest.mock('fs', () => {
+  const realFs = jest.requireActual('fs');
+  jest.spyOn(realFs, 'readFile');
+  return realFs;
+});
+
 expect.addSnapshotSerializer(createAbsolutePathSerializer());
 
 jest.requireMock('execa').mockImplementation(async (cmd: string, args: string[], opts: object) => {
@@ -46,28 +67,35 @@ jest.requireMock('execa').mockImplementation(async (cmd: string, args: string[],
   };
 });
 
-jest.requireMock('./get_changes.ts').getChanges.mockImplementation(
-  async () =>
-    new Map([
-      ['/foo/bar/a', 'modified'],
-      ['/foo/bar/b', 'modified'],
-      ['/foo/bar/c', 'deleted'],
-    ])
-);
-
 describe('getOptimizerCacheKey()', () => {
-  it('uses latest commit and changes files to create unique value', async () => {
+  it('uses latest commit, bootstrap cache, and changed files to create unique value', async () => {
+    jest
+      .requireMock('fs')
+      .readFile.mockImplementation(
+        (path: string, enc: string, cb: (err: null, file: string) => void) => {
+          expect(path).toBe(
+            Path.resolve(REPO_ROOT, 'packages/kbn-optimizer/target/.bootstrap-cache')
+          );
+          expect(enc).toBe('utf8');
+          cb(null, '<bootstrap cache>');
+        }
+      );
+
     const config = OptimizerConfig.create({
       repoRoot: REPO_ROOT,
     });
 
     await expect(getOptimizerCacheKey(config)).resolves.toMatchInlineSnapshot(`
             Object {
+              "bootstrap": "<bootstrap cache>",
               "deletedPaths": Array [
                 "/foo/bar/c",
               ],
               "lastCommit": "<last commit sha>",
-              "modifiedPaths": Object {},
+              "modifiedTimes": Object {
+                "/foo/bar/a": 12345,
+                "/foo/bar/b": 12345,
+              },
               "workerConfig": Object {
                 "browserslistEnv": "dev",
                 "cache": true,

packages/kbn-optimizer/src/optimizer/cache_keys.ts

@@ -18,6 +18,8 @@
  */
 
 import Path from 'path';
+import Fs from 'fs';
+import { promisify } from 'util';
 
 import Chalk from 'chalk';
 import execa from 'execa';
@@ -116,9 +118,10 @@ export function reformatJestDiff(diff: string | null) {
 
 export interface OptimizerCacheKey {
   readonly lastCommit: string | undefined;
+  readonly bootstrap: string | undefined;
   readonly workerConfig: WorkerConfig;
   readonly deletedPaths: string[];
-  readonly modifiedPaths: Record<string, number>;
+  readonly modifiedTimes: Record<string, number>;
 }
 
 async function getLastCommit() {
@@ -133,21 +136,45 @@ async function getLastCommit() {
   return stdout.trim() || undefined;
 }
 
+async function getBootstrapCacheKey() {
+  try {
+    return await promisify(Fs.readFile)(
+      Path.resolve(OPTIMIZER_DIR, 'target/.bootstrap-cache'),
+      'utf8'
+    );
+  } catch (error) {
+    if (error?.code !== 'ENOENT') {
+      throw error;
+    }
+    return undefined;
+  }
+}
+
 export async function getOptimizerCacheKey(config: OptimizerConfig) {
-  const changes = Array.from((await getChanges(OPTIMIZER_DIR)).entries());
+  const [changes, lastCommit, bootstrap] = await Promise.all([
+    getChanges(OPTIMIZER_DIR),
+    getLastCommit(),
+    getBootstrapCacheKey(),
+  ] as const);
+
+  const deletedPaths: string[] = [];
+  const modifiedPaths: string[] = [];
+  for (const [path, type] of changes) {
+    (type === 'deleted' ? deletedPaths : modifiedPaths).push(path);
+  }
 
   const cacheKeys: OptimizerCacheKey = {
-    lastCommit: await getLastCommit(),
     workerConfig: config.getWorkerConfig('♻'),
-    deletedPaths: changes.filter(e => e[1] === 'deleted').map(e => e[0]),
-    modifiedPaths: {} as Record<string, number>,
+    lastCommit,
+    bootstrap,
+    deletedPaths,
+    modifiedTimes: {} as Record<string, number>,
   };
 
-  const modified = changes.filter(e => e[1] === 'modified').map(e => e[0]);
-  const mtimes = await getMtimes(modified);
+  const mtimes = await getMtimes(modifiedPaths);
   for (const [path, mtime] of Array.from(mtimes.entries()).sort(ascending(e => e[0]))) {
     if (typeof mtime === 'number') {
-      cacheKeys.modifiedPaths[path] = mtime;
+      cacheKeys.modifiedTimes[path] = mtime;
     }
   }