fixup! perf(@angular/build): overlap library asset resolution and deduplicate output mkdir calls

Author: alan-agius4

packages/angular/build/src/builders/library/pipeline/build-action.ts

@@ -71,13 +71,8 @@ export async function buildAction(actionContext: BuildActionContext): Promise<Ex
       return result;
     }
 
-    const collectedAssetsPromise =
-      actionContext.collectedAssets ?? buildState.collectAssets(options, modifiedFiles);
-    if (collectedAssetsPromise instanceof Promise) {
-      // Prevent unhandled promise rejections if compilation or bundling returns early.
-      collectedAssetsPromise.catch(() => {});
-    }
-
+    let collectedAssetsPromise: CollectedAssets | Promise<CollectedAssets> | undefined =
+      actionContext.collectedAssets;
     const filesToEmit: OutputFile[] = [];
 
     if (shouldCompileEntryPoints) {
@@ -106,6 +101,13 @@ export async function buildAction(actionContext: BuildActionContext): Promise<Ex
         return result;
       }
 
+      if (!collectedAssetsPromise) {
+        const promise = buildState.collectAssets(options, modifiedFiles);
+        // Prevent unhandled promise rejections if bundling returns early.
+        promise.catch(() => {});
+        collectedAssetsPromise = promise;
+      }
+
       const itemsToBundle = collectEntryPointsToBundle(options, buildState);
       let bundleOutput: BundleEntryPointsOutput;
       try {
@@ -158,17 +160,26 @@ export async function buildAction(actionContext: BuildActionContext): Promise<Ex
       filesToEmit.push(...manifestFiles);
     }
 
-    const collectedAssets = await collectedAssetsPromise;
+    const collectedAssets = await (collectedAssetsPromise ??
+      buildState.collectAssets(options, modifiedFiles));
     filesToEmit.push(...collectedAssets.filesToEmit);
 
+    const emitPromise = emitFilesToDisk(filesToEmit, (file) =>
+      path.posix.join(options.outputPath, file.path),
+    );
+
     const filesToDelete = buildState.recordEmittedOutputs(collectedAssets, manifestFiles);
 
-    await Promise.all([
-      deleteFilesFromDisk(
-        Array.from(filesToDelete, (file) => path.posix.join(options.outputPath, file)),
-      ),
-      emitFilesToDisk(filesToEmit, (file) => path.posix.join(options.outputPath, file.path)),
-    ]);
+    if (filesToDelete.size) {
+      await Promise.all([
+        emitPromise,
+        deleteFilesFromDisk(
+          Array.from(filesToDelete, (file) => path.posix.join(options.outputPath, file)),
+        ),
+      ]);
+    } else {
+      await emitPromise;
+    }
   } catch (error) {
     assertIsError(error);
     result.addError(error.message);

packages/angular/build/src/utils/disk-files.ts

@@ -50,13 +50,7 @@ export async function emitFilesToDisk<T extends EmittableFile = EmittableFile>(
       let mkdirPromise = directoryCreationPromises.get(fileBasePath);
       if (!mkdirPromise) {
         mkdirPromise = mkdir(fileBasePath, { recursive: true });
-        for (
-          let currentDir = fileBasePath;
-          !directoryCreationPromises.has(currentDir);
-          currentDir = dirname(currentDir)
-        ) {
-          directoryCreationPromises.set(currentDir, mkdirPromise);
-        }
+        directoryCreationPromises.set(fileBasePath, mkdirPromise);
       }
       await mkdirPromise;
     }

packages/angular/build/src/utils/disk-files_spec.ts

@@ -39,8 +39,6 @@ describe('disk-files', () => {
           contents: new TextEncoder().encode('mem-1'),
         },
         { origin: 'memory', path: 'nested/a/mem2.txt', contents: 'mem-2' },
-        { origin: 'memory', path: 'nested/parent.txt', contents: 'parent-mem' },
-        { origin: 'memory', path: 'root.txt', contents: 'root-mem' },
         { origin: 'disk', path: 'nested/b/disk1.txt', source: sourceFile },
         { origin: 'disk', path: 'nested/c/disk2.txt', source: sourceFile },
         { origin: 'memory', path: 'skipped/file.txt', contents: 'should-not-exist' },
@@ -53,8 +51,6 @@ describe('disk-files', () => {
 
       expect(await readFile(join(outDir, 'nested/a/mem1.txt'), 'utf-8')).toBe('mem-1');
       expect(await readFile(join(outDir, 'nested/a/mem2.txt'), 'utf-8')).toBe('mem-2');
-      expect(await readFile(join(outDir, 'nested/parent.txt'), 'utf-8')).toBe('parent-mem');
-      expect(await readFile(join(outDir, 'root.txt'), 'utf-8')).toBe('root-mem');
       expect(await readFile(join(outDir, 'nested/b/disk1.txt'), 'utf-8')).toBe('from-disk');
       expect(await readFile(join(outDir, 'nested/c/disk2.txt'), 'utf-8')).toBe('from-disk');
       expect(existsSync(join(outDir, 'skipped/file.txt'))).toBeFalse();