add lazy compilation for entrypoints

declarations/WebpackOptions.d.ts

@@ -1042,7 +1042,7 @@ export interface Experiments {
 	 */
 	layers?: boolean;
 	/**
-	 * Compile import()s only when they are accessed.
+	 * Compile entrypoints and import()s only when they are accessed.
 	 */
 	lazyCompilation?:
 		| boolean
@@ -1064,6 +1064,10 @@ export interface Experiments {
 				 * A custom client.
 				 */
 				client?: string;
+				/**
+				 * Enable/disable lazy compilation for entries.
+				 */
+				entries?: boolean;
 		  };
 	/**
 	 * Allow output javascript files as module source type.

examples/lazy-compilation/webpack.config.js

@@ -10,7 +10,9 @@ module.exports = {
 		idleTimeout: 5000
 	},
 	experiments: {
-		lazyCompilation: true
+		lazyCompilation: {
+			entries: false
+		}
 	},
 	devServer: {
 		hot: true,

hot/lazy-compilation-node.js

@@ -2,16 +2,12 @@
 
 "use strict";
 
-if (!module.hot) {
-	throw new Error(
-		"Environment doesn't support lazy compilation (requires Hot Module Replacement enabled)"
-	);
-}
-
 var urlBase = decodeURIComponent(__resourceQuery.slice(1));
 exports.keepAlive = function (options) {
 	var data = options.data;
 	var onError = options.onError;
+	var active = options.active;
+	var module = options.module;
 	var response;
 	var request = require("http").request(
 		urlBase + data,
@@ -22,6 +18,11 @@ exports.keepAlive = function (options) {
 		function (res) {
 			response = res;
 			response.on("error", errorHandler);
+			if (!active && !module.hot) {
+				console.log(
+					"Hot Module Replacement is not enabled. Waiting for process restart..."
+				);
+			}
 		}
 	);
 	function errorHandler(err) {

hot/lazy-compilation-web.js

@@ -2,9 +2,9 @@
 
 "use strict";
 
-if (typeof EventSource !== "function" || !module.hot) {
+if (typeof EventSource !== "function") {
 	throw new Error(
-		"Environment doesn't support lazy compilation (requires EventSource and Hot Module Replacement enabled)"
+		"Environment doesn't support lazy compilation (requires EventSource)"
 	);
 }
 
@@ -45,12 +45,19 @@ var updateEventSource = function updateEventSource() {
 exports.keepAlive = function (options) {
 	var data = options.data;
 	var onError = options.onError;
+	var active = options.active;
+	var module = options.module;
 	errorHandlers.add(onError);
 	var value = activeKeys.get(data) || 0;
 	activeKeys.set(data, value + 1);
 	if (value === 0) {
 		updateEventSource();
 	}
+	if (!active && !module.hot) {
+		console.log(
+			"Hot Module Replacement is not enabled. Waiting for process restart..."
+		);
+	}
 
 	return function () {
 		errorHandlers.delete(onError);

lib/WebpackOptionsApply.js

@@ -256,7 +256,10 @@ class WebpackOptionsApply extends OptionsApply {
 						options.experiments.lazyCompilation.client) ||
 					`webpack/hot/lazy-compilation-${
 						options.externalsPresets.node ? "node" : "web"
-					}.js`
+					}.js`,
+				entries:
+					typeof options.experiments.lazyCompilation !== "object" ||
+					options.experiments.lazyCompilation.entries !== false
 			}).apply(compiler);
 		}
 

lib/hmr/LazyCompilationPlugin.js

@@ -59,12 +59,8 @@ class LazyCompilationDependency extends Dependency {
 registerNotSerializable(LazyCompilationDependency);
 
 class LazyCompilationProxyModule extends Module {
-	constructor(originalModule, request, client, data, active) {
+	constructor(context, originalModule, request, client, data, active) {
-		super(
+		super("lazy-compilation-proxy", context, originalModule.layer);
-			"lazy-compilation-proxy",
-			originalModule.context,
-			originalModule.layer
-		);
 		this.originalModule = originalModule;
 		this.request = request;
 		this.client = client;
@@ -172,14 +168,16 @@ class LazyCompilationProxyModule extends Module {
 			.dependencies[0]);
 		const clientModule = moduleGraph.getModule(clientDep);
 		const block = this.blocks[0];
-		const keepActive = Template.asString([
+		const client = Template.asString([
 			`var client = ${runtimeTemplate.moduleExports({
 				module: clientModule,
 				chunkGraph,
 				request: clientDep.userRequest,
 				runtimeRequirements
 			})}`,
-			`var data = ${JSON.stringify(this.data)};`,
+			`var data = ${JSON.stringify(this.data)};`
+		]);
+		const keepActive = Template.asString([
 			`var dispose = client.keepAlive({ data, active: ${JSON.stringify(
 				!!block
 			)}, module, onError });`
@@ -189,11 +187,7 @@ class LazyCompilationProxyModule extends Module {
 			const dep = block.dependencies[0];
 			const module = moduleGraph.getModule(dep);
 			source = Template.asString([
-				"module.hot.accept();",
+				client,
-				`module.hot.accept(${JSON.stringify(
-					chunkGraph.getModuleId(module)
-				)}, function() { module.hot.invalidate(); });`,
-				"module.hot.dispose(function(data) { delete data.resolveSelf; dispose(data); });",
 				`module.exports = ${runtimeTemplate.moduleNamespacePromise({
 					chunkGraph,
 					block,
@@ -203,17 +197,31 @@ class LazyCompilationProxyModule extends Module {
 					message: "import()",
 					runtimeRequirements
 				})};`,
-				"if (module.hot.data && module.hot.data.resolveSelf) module.hot.data.resolveSelf(module.exports);",
+				"if (module.hot) {",
+				Template.indent([
+					"module.hot.accept();",
+					`module.hot.accept(${JSON.stringify(
+						chunkGraph.getModuleId(module)
+					)}, function() { module.hot.invalidate(); });`,
+					"module.hot.dispose(function(data) { delete data.resolveSelf; dispose(data); });",
+					"if (module.hot.data && module.hot.data.resolveSelf) module.hot.data.resolveSelf(module.exports);"
+				]),
+				"}",
 				"function onError() { /* ignore */ }",
 				keepActive
 			]);
 		} else {
 			source = Template.asString([
-				"module.hot.accept();",
+				client,
 				"var resolveSelf, onError;",
 				`module.exports = new Promise(function(resolve, reject) { resolveSelf = resolve; onError = reject; });`,
+				"if (module.hot) {",
+				Template.indent([
+					"module.hot.accept();",
 					"if (module.hot.data && module.hot.data.resolveSelf) module.hot.data.resolveSelf(module.exports);",
-				"module.hot.dispose(function(data) { data.resolveSelf = resolveSelf; dispose(data); });",
+					"module.hot.dispose(function(data) { data.resolveSelf = resolveSelf; dispose(data); });"
+				]),
+				"}",
 				keepActive
 			]);
 		}
@@ -263,10 +271,12 @@ class LazyCompilationPlugin {
 	 * @param {Object} options options
 	 * @param {(function(Compiler, string, function(Error?, any?): void): void) | function(Compiler, string): Promise<any>} options.backend the backend
 	 * @param {string} options.client the client reference
+	 * @param {boolean} options.entries true, when entries are lazy compiled
 	 */
-	constructor({ backend, client }) {
+	constructor({ backend, client, entries }) {
 		this.backend = backend;
 		this.client = client;
+		this.entries = entries;
 	}
 	/**
 	 * Apply the plugin
@@ -292,20 +302,28 @@ class LazyCompilationPlugin {
 				}
 			}
 		);
-		compiler.hooks.compilation.tap(
+		compiler.hooks.thisCompilation.tap(
 			"LazyCompilationPlugin",
 			(compilation, { normalModuleFactory }) => {
 				normalModuleFactory.hooks.module.tap(
 					"LazyCompilationPlugin",
 					(originalModule, createData, resolveData) => {
 						if (
-							resolveData.dependencies.every(dep => dep.type === "import()")
+							resolveData.dependencies.every(
+								dep =>
+									dep.type === "import()" ||
+									(this.entries && dep.type === "entry")
+							) &&
+							!/webpack[/\\]hot[/\\]|webpack-dev-server[/\\]client/.test(
+								resolveData.request
+							)
 						) {
 							const moduleInfo = backend.module(originalModule);
 							if (!moduleInfo) return;
 							const { client, data, active } = moduleInfo;
 
 							return new LazyCompilationProxyModule(
+								compiler.context,
 								originalModule,
 								resolveData.request,
 								client,

schemas/WebpackOptions.json

@@ -582,7 +582,7 @@
           "type": "boolean"
         },
         "lazyCompilation": {
-          "description": "Compile import()s only when they are accessed.",
+          "description": "Compile entrypoints and import()s only when they are accessed.",
           "anyOf": [
             {
               "type": "boolean"
@@ -599,6 +599,10 @@
                 "client": {
                   "description": "A custom client.",
                   "type": "string"
+                },
+                "entries": {
+                  "description": "Enable/disable lazy compilation for entries.",
+                  "type": "boolean"
                 }
               }
             }

test/hotCases/lazy-compilation/simple/webpack.config.js

@@ -3,6 +3,8 @@
 /** @type {import("../../../../").Configuration} */
 module.exports = {
 	experiments: {
-		lazyCompilation: true
+		lazyCompilation: {
+			entries: false
+		}
 	}
 };

types.d.ts

@@ -2956,7 +2956,7 @@ declare interface Experiments {
 	layers?: boolean;
 
 	/**
-	 * Compile import()s only when they are accessed.
+	 * Compile entrypoints and import()s only when they are accessed.
 	 */
 	lazyCompilation?:
 		| boolean
@@ -2975,6 +2975,10 @@ declare interface Experiments {
 				 * A custom client.
 				 */
 				client?: string;
+				/**
+				 * Enable/disable lazy compilation for entries.
+				 */
+				entries?: boolean;
 		  };
 
 	/**