Package on main thread for small rebuilds

packages/core/core/src/PackagerRunner.js

@@ -67,6 +67,7 @@ type Opts = {|
   report: ReportFn,
   previousDevDeps: Map<string, string>,
   previousInvalidations: Array<RequestInvalidation>,
+  useFarm: boolean,
 |};
 
 export type PackageRequestResult = {|
@@ -109,20 +110,23 @@ export default class PackagerRunner {
   devDepRequests: Map<string, DevDepRequest>;
   invalidations: Map<string, RequestInvalidation>;
   previousInvalidations: Array<RequestInvalidation>;
+  useFarm: boolean;
 
   constructor({
     config,
     options,
     report,
     previousDevDeps,
     previousInvalidations,
+    useFarm,
   }: Opts) {
     this.config = config;
     this.options = options;
     this.report = report;
     this.previousDevDeps = previousDevDeps;
     this.devDepRequests = new Map();
     this.previousInvalidations = previousInvalidations;
+    this.useFarm = useFarm;
     this.invalidations = new Map();
     this.pluginOptions = new PluginOptions(
       optionsProxy(this.options, option => {
@@ -325,6 +329,7 @@ export default class PackagerRunner {
       type: 'buildProgress',
       phase: 'packaging',
       bundle,
+      bundleGraph: this.useFarm ? undefined : bundleGraph,
     });
 
     let packager = await this.config.getPackager(bundle.name);
@@ -418,6 +423,7 @@ export default class PackagerRunner {
       type: 'buildProgress',
       phase: 'optimizing',
       bundle,
+      bundleGraph: this.useFarm ? undefined : internalBundleGraph,
     });
 
     let optimized = {

packages/core/core/src/ReporterRunner.js

@@ -64,10 +64,12 @@ export default class ReporterRunner {
       let bundle: InternalBundle = event.bundle;
       // Convert any internal bundles back to their public equivalents as reporting
       // is public api
-      let bundleGraph = this.workerFarm.workerApi.getSharedReference(
-        // $FlowFixMe
-        bundleGraphRef,
-      );
+      let bundleGraph =
+        event.bundleGraph ??
+        this.workerFarm.workerApi.getSharedReference(
+          // $FlowFixMe
+          bundleGraphRef,
+        );
       invariant(bundleGraph instanceof BundleGraph);
       // $FlowFixMe[incompatible-call]
       this.report({
@@ -131,5 +133,17 @@ export function reportWorker(workerApi: WorkerApi, event: ReporterEvent) {
 }
 
 export function report(event: ReporterEvent) {
-  bus.emit('reporterEvent', event);
+  if (
+    event.bundleGraph &&
+    event.type === 'buildProgress' &&
+    (event.phase === 'optimizing' || event.phase === 'packaging')
+  ) {
+    bus.emit('reporterEvent', {
+      ...event,
+      bundle: bundleToInternalBundle(event.bundle),
+      bundleGraphRef: event.bundleGraph,
+    });
+  } else {
+    bus.emit('reporterEvent', event);
+  }
 }

packages/core/core/src/requests/PackageRequest.js

@@ -18,7 +18,7 @@ import createParcelConfigRequest from './ParcelConfigRequest';
 type PackageRequestInput = {|
   bundleGraph: BundleGraph,
   bundle: Bundle,
-  bundleGraphReference: SharedReference,
+  bundleGraphReference?: SharedReference,
   optionsRef: SharedReference,
 |};
 
@@ -54,10 +54,12 @@ async function run({input, api, farm}: RunInput) {
   let {cachePath} = nullthrows(
     await api.runRequest<null, ConfigAndCachePath>(createParcelConfigRequest()),
   );
+
   let {devDepRequests, configRequests, bundleInfo, invalidations} =
     await runPackage({
       bundle,
-      bundleGraphReference,
+      bundleGraphReference:
+        bundleGraphReference == null ? input.bundleGraph : bundleGraphReference,
       optionsRef,
       configCachePath: cachePath,
       previousDevDeps: devDeps,

packages/core/core/src/requests/WriteBundlesRequest.js

@@ -49,10 +49,6 @@ export default function createWriteBundlesRequest(
 
 async function run({input, api, farm, options}: RunInput) {
   let {bundleGraph, optionsRef} = input;
-  let {ref, dispose} = await farm.createSharedReference(
-    bundleGraph,
-    serialize(bundleGraph),
-  );
 
   api.invalidateOnOptionChange('shouldContentHash');
 
@@ -83,6 +79,20 @@ async function run({input, api, farm, options}: RunInput) {
     return true;
   });
 
+  let ref;
+  let dispose;
+
+  // Create shared reference in WorkerFarm if we need to change multiple bundles and if we
+  // can't skip the subrequests for all the bundles
+  if (
+    bundles.length > 1 &&
+    bundles.some(b => !api.canSkipSubrequest(bundleGraph.getHash(b)))
+  ) {
+    ({ref, dispose} = await farm.createSharedReference(
+      bundleGraph,
+      serialize(bundleGraph),
+    ));
+  }
   try {
     await Promise.all(
       bundles.map(async bundle => {
@@ -133,7 +143,9 @@ async function run({input, api, farm, options}: RunInput) {
     api.storeResult(res);
     return res;
   } finally {
-    await dispose();
+    if (dispose) {
+      await dispose();
+    }
   }
 }
 

packages/core/core/src/worker.js

@@ -17,7 +17,7 @@ import Transformation, {
   type TransformationOpts,
   type TransformationResult,
 } from './Transformation';
-import {reportWorker} from './ReporterRunner';
+import {reportWorker, report} from './ReporterRunner';
 import PackagerRunner, {type PackageRequestResult} from './PackagerRunner';
 import Validation, {type ValidationOpts} from './Validation';
 import ParcelConfig from './ParcelConfig';
@@ -121,25 +121,32 @@ export async function runPackage(
     previousInvalidations,
   }: {|
     bundle: Bundle,
-    bundleGraphReference: SharedReference,
+    bundleGraphReference: SharedReference | BundleGraph,
     configCachePath: string,
     optionsRef: SharedReference,
     previousDevDeps: Map<string, string>,
     invalidDevDeps: Array<DevDepSpecifier>,
     previousInvalidations: Array<RequestInvalidation>,
   |},
 ): Promise<PackageRequestResult> {
-  let bundleGraph = workerApi.getSharedReference(bundleGraphReference);
+  let bundleGraph =
+    typeof bundleGraphReference === 'number'
+      ? workerApi.getSharedReference(bundleGraphReference)
+      : bundleGraphReference;
   invariant(bundleGraph instanceof BundleGraph);
   let options = loadOptions(optionsRef, workerApi);
   let parcelConfig = await loadConfig(configCachePath, options);
 
   let runner = new PackagerRunner({
     config: parcelConfig,
     options,
-    report: reportWorker.bind(null, workerApi),
+    report:
+      typeof bundleGraphReference === 'number'
+        ? reportWorker.bind(null, workerApi)
+        : report,
     previousDevDeps,
     previousInvalidations,
+    useFarm: typeof bundleGraphReference === 'number' ? true : false,
   });
 
   return runner.run(bundleGraph, bundle, invalidDevDeps);

packages/core/types/index.js

@@ -5,6 +5,7 @@ import type SourceMap from '@parcel/source-map';
 import type {FileSystem} from '@parcel/fs';
 import type WorkerFarm from '@parcel/workers';
 import type {PackageManager} from '@parcel/package-manager';
+import type InternalBundleGraph from '../core/src/BundleGraph';
 import type {
   Diagnostic,
   Diagnostifiable,
@@ -1754,6 +1755,7 @@ export type PackagingProgressEvent = {|
   +type: 'buildProgress',
   +phase: 'packaging',
   +bundle: NamedBundle,
+  +bundleGraph?: InternalBundleGraph,
 |};
 
 /**
@@ -1764,6 +1766,7 @@ export type OptimizingProgressEvent = {|
   +type: 'buildProgress',
   +phase: 'optimizing',
   +bundle: NamedBundle,
+  +bundleGraph?: InternalBundleGraph,
 |};
 
 /**