allow to merge multiple hmr updates which calling hot.check while previous update is ready

lib/Compilation.js

@@ -276,6 +276,7 @@ const { isSourceEqual } = require("./util/source");
  * @typedef {Object} PathData
  * @property {ChunkGraph=} chunkGraph
  * @property {string=} hash
+ * @property {string=} index
  * @property {function(number): string=} hashWithLength
  * @property {(Chunk|ChunkPathData)=} chunk
  * @property {(Module|ModulePathData)=} module
@@ -831,7 +832,7 @@ BREAKING CHANGE: Asset processing hooks in Compilation has been merged into a si
 			/** @type {SyncHook<[Chunk, string]>} */
 			chunkAsset: new SyncHook(["chunk", "filename"]),
 
-			/** @type {SyncWaterfallHook<[string, object, AssetInfo]>} */
+			/** @type {SyncWaterfallHook<[string, PathData, AssetInfo]>} */
 			assetPath: new SyncWaterfallHook(["path", "options", "assetInfo"]),
 
 			/** @type {SyncBailHook<[], boolean>} */
@@ -996,6 +997,12 @@ BREAKING CHANGE: Asset processing hooks in Compilation has been merged into a si
 		/** @private @type {Map<string, Module>} */
 		this._modules = new Map();
 		this.records = null;
+		/** @type {string | undefined} */
+		this.hash = undefined;
+		/** @type {string | undefined} */
+		this.fullHash = undefined;
+		/** @type {number | undefined} */
+		this.index = undefined;
 		/** @type {string[]} */
 		this.additionalChunkAssets = [];
 		/** @type {CompilationAssets} */
@@ -2781,6 +2788,11 @@ BREAKING CHANGE: Asset processing hooks in Compilation has been merged into a si
 			ChunkGraph.setChunkGraphForModule(module, chunkGraph);
 		}
 
+		this.index =
+			this.records && this.records.index !== undefined
+				? this.records.index + 1
+				: 0;
+
 		this.hooks.seal.call();
 
 		this.logger.time("optimize dependencies");
@@ -3056,6 +3068,7 @@ Or do you want to use the entrypoints '${name}' and '${runtime}' independently o
 
 									this.summarizeDependencies();
 									if (shouldRecord) {
+										this.records.index = this.index;
 										this.hooks.record.call(this, this.records);
 									}
 
@@ -4442,6 +4455,7 @@ This prevents using hashes of each other and should be avoided.`);
 				try {
 					manifest = this.getRenderManifest({
 						chunk,
+						index: `${this.index}`,
 						hash: this.hash,
 						fullHash: this.fullHash,
 						outputOptions,
@@ -4586,9 +4600,10 @@ This prevents using hashes of each other and should be avoided.`);
 	 * @returns {string} interpolated path
 	 */
 	getPath(filename, data = {}) {
-		if (!data.hash) {
+		if (!data.hash || !data.index) {
 			data = {
 				hash: this.hash,
+				index: `${this.index}`,
 				...data
 			};
 		}
@@ -4601,9 +4616,10 @@ This prevents using hashes of each other and should be avoided.`);
 	 * @returns {{ path: string, info: AssetInfo }} interpolated path and asset info
 	 */
 	getPathWithInfo(filename, data = {}) {
-		if (!data.hash) {
+		if (!data.hash || !data.index) {
 			data = {
 				hash: this.hash,
+				index: `${this.index}`,
 				...data
 			};
 		}

lib/HotModuleReplacementPlugin.js

@@ -23,6 +23,8 @@ const JavascriptParser = require("./javascript/JavascriptParser");
 const {
 	evaluateToIdentifier
 } = require("./javascript/JavascriptParserHelpers");
+const CompilationIndexRuntimeModule = require("./runtime/CompilationIndexRuntimeModule");
+const GetFullHashRuntimeModule = require("./runtime/GetFullHashRuntimeModule");
 const { find, isSubset } = require("./util/SetHelpers");
 const TupleSet = require("./util/TupleSet");
 const { compareModulesById } = require("./util/comparators");
@@ -48,6 +50,10 @@ const {
  * @property {SyncBailHook<[TODO, string[]], void>} hotAcceptWithoutCallback
  */
 
+const isOutOfBandModule = module =>
+	module instanceof CompilationIndexRuntimeModule ||
+	module instanceof GetFullHashRuntimeModule;
+
 /** @type {WeakMap<JavascriptParser, HMRJavascriptParserHooks>} */
 const parserHooksMap = new WeakMap();
 
@@ -342,6 +348,7 @@ class HotModuleReplacementPlugin {
 							chunkGraph.getChunkFullHashModulesSet(chunk);
 						if (fullHashModulesInThisChunk !== undefined) {
 							for (const module of fullHashModulesInThisChunk) {
+								if (isOutOfBandModule(module)) continue;
 								fullHashModules.add(module, chunk);
 							}
 						}
@@ -350,6 +357,7 @@ class HotModuleReplacementPlugin {
 							if (records.chunkModuleHashes) {
 								if (fullHashModulesInThisChunk !== undefined) {
 									for (const module of modules) {
+										if (isOutOfBandModule(module)) continue;
 										const key = `${chunk.id}|${module.identifier()}`;
 										const hash = getModuleHash(module);
 										if (
@@ -370,6 +378,7 @@ class HotModuleReplacementPlugin {
 									}
 								} else {
 									for (const module of modules) {
+										if (isOutOfBandModule(module)) continue;
 										const key = `${chunk.id}|${module.identifier()}`;
 										const hash = getModuleHash(module);
 										if (records.chunkModuleHashes[key] !== hash) {
@@ -381,6 +390,7 @@ class HotModuleReplacementPlugin {
 							} else {
 								if (fullHashModulesInThisChunk !== undefined) {
 									for (const module of modules) {
+										if (isOutOfBandModule(module)) continue;
 										const key = `${chunk.id}|${module.identifier()}`;
 										const hash = getModuleHash(module);
 										if (
@@ -452,6 +462,7 @@ class HotModuleReplacementPlugin {
 									compilation.outputOptions.hotUpdateMainFilename,
 									{
 										hash: records.hash,
+										index: `${records.index}`,
 										runtime
 									}
 								);
@@ -625,6 +636,7 @@ class HotModuleReplacementPlugin {
 									chunk: hotUpdateChunk,
 									hash: records.hash,
 									fullHash: records.hash,
+									index: `${records.index}`,
 									outputOptions: compilation.outputOptions,
 									moduleTemplates: compilation.moduleTemplates,
 									dependencyTemplates: compilation.dependencyTemplates,
@@ -710,6 +722,8 @@ To fix this, make sure to include [runtime] in the output.hotUpdateMainFilename
 							{ removedChunkIds, removedModules, updatedChunkIds, assetInfo }
 						] of hotUpdateMainContentByFilename) {
 							const hotUpdateMainJson = {
+								n: compilation.index,
+								h: compilation.hash,
 								c: Array.from(updatedChunkIds),
 								r: Array.from(removedChunkIds),
 								m:

lib/RuntimeGlobals.js

@@ -140,6 +140,11 @@ exports.nodeModuleDecorator = "__webpack_require__.nmd";
  */
 exports.getFullHash = "__webpack_require__.h";
 
+/**
+ * the compilation index
+ */
+exports.compilationIndex = "__webpack_require__.N";
+
 /**
  * an object containing all installed WebAssembly.Instance export objects keyed by module id
  */

lib/RuntimePlugin.js

@@ -12,6 +12,7 @@ const AsyncModuleRuntimeModule = require("./runtime/AsyncModuleRuntimeModule");
 const AutoPublicPathRuntimeModule = require("./runtime/AutoPublicPathRuntimeModule");
 const CompatGetDefaultExportRuntimeModule = require("./runtime/CompatGetDefaultExportRuntimeModule");
 const CompatRuntimeModule = require("./runtime/CompatRuntimeModule");
+const CompilationIndexRuntimeModule = require("./runtime/CompilationIndexRuntimeModule");
 const CreateFakeNamespaceObjectRuntimeModule = require("./runtime/CreateFakeNamespaceObjectRuntimeModule");
 const CreateScriptUrlRuntimeModule = require("./runtime/CreateScriptUrlRuntimeModule");
 const DefinePropertyGettersRuntimeModule = require("./runtime/DefinePropertyGettersRuntimeModule");
@@ -44,6 +45,7 @@ const GLOBALS_ON_REQUIRE = [
 	RuntimeGlobals.ensureChunk,
 	RuntimeGlobals.entryModuleId,
 	RuntimeGlobals.getFullHash,
+	RuntimeGlobals.compilationIndex,
 	RuntimeGlobals.global,
 	RuntimeGlobals.makeNamespaceObject,
 	RuntimeGlobals.moduleCache,
@@ -84,6 +86,16 @@ const TREE_DEPENDENCIES = {
 	[RuntimeGlobals.shareScopeMap]: [RuntimeGlobals.hasOwnProperty]
 };
 
+const handleRuntimeModuleAssetPath = (assetPath, runtimeRequirements) => {
+	if (typeof assetPath !== "string") return;
+	if (/\[(full)?hash(:\d+)?\]/.test(assetPath)) {
+		runtimeRequirements.add(RuntimeGlobals.getFullHash);
+	}
+	if (/\[index\]/.test(assetPath)) {
+		runtimeRequirements.add(RuntimeGlobals.compilationIndex);
+	}
+};
+
 class RuntimePlugin {
 	/**
 	 * @param {Compiler} compiler the Compiler
@@ -203,6 +215,15 @@ class RuntimePlugin {
 					}
 					return true;
 				});
+			compilation.hooks.runtimeRequirementInTree
+				.for(RuntimeGlobals.compilationIndex)
+				.tap("RuntimePlugin", chunk => {
+					compilation.addRuntimeModule(
+						chunk,
+						new CompilationIndexRuntimeModule(compilation.index)
+					);
+					return true;
+				});
 			compilation.hooks.runtimeRequirementInTree
 				.for(RuntimeGlobals.global)
 				.tap("RuntimePlugin", chunk => {
@@ -229,14 +250,10 @@ class RuntimePlugin {
 			compilation.hooks.runtimeRequirementInTree
 				.for(RuntimeGlobals.getChunkScriptFilename)
 				.tap("RuntimePlugin", (chunk, set) => {
-					if (
+					handleRuntimeModuleAssetPath(
-						typeof compilation.outputOptions.chunkFilename === "string" &&
+						compilation.outputOptions.chunkFilename,
-						/\[(full)?hash(:\d+)?\]/.test(
+						set
-							compilation.outputOptions.chunkFilename
+					);
-						)
-					) {
-						set.add(RuntimeGlobals.getFullHash);
-					}
 					compilation.addRuntimeModule(
 						chunk,
 						new GetChunkFilenameRuntimeModule(
@@ -256,12 +273,10 @@ class RuntimePlugin {
 			compilation.hooks.runtimeRequirementInTree
 				.for(RuntimeGlobals.getChunkUpdateScriptFilename)
 				.tap("RuntimePlugin", (chunk, set) => {
-					if (
+					handleRuntimeModuleAssetPath(
-						/\[(full)?hash(:\d+)?\]/.test(
+						compilation.outputOptions.hotUpdateChunkFilename,
-							compilation.outputOptions.hotUpdateChunkFilename
+						set
-						)
+					);
-					)
-						set.add(RuntimeGlobals.getFullHash);
 					compilation.addRuntimeModule(
 						chunk,
 						new GetChunkFilenameRuntimeModule(
@@ -277,13 +292,10 @@ class RuntimePlugin {
 			compilation.hooks.runtimeRequirementInTree
 				.for(RuntimeGlobals.getUpdateManifestFilename)
 				.tap("RuntimePlugin", (chunk, set) => {
-					if (
+					handleRuntimeModuleAssetPath(
-						/\[(full)?hash(:\d+)?\]/.test(
+						compilation.outputOptions.hotUpdateMainFilename,
-							compilation.outputOptions.hotUpdateMainFilename
+						set
-						)
+					);
-					) {
-						set.add(RuntimeGlobals.getFullHash);
-					}
 					compilation.addRuntimeModule(
 						chunk,
 						new GetMainFilenameRuntimeModule(

lib/Template.js

@@ -41,6 +41,7 @@ const MATCH_PADDED_HYPHENS_REPLACE_REGEX = /^-|-$/g;
 /**
  * @typedef {Object} RenderManifestOptions
  * @property {Chunk} chunk the chunk used to render
+ * @property {string} index
  * @property {string} hash
  * @property {string} fullHash
  * @property {OutputOptions} outputOptions

lib/TemplatedPathPlugin.js

@@ -147,6 +147,7 @@ const replacePathVariables = (path, data, assetInfo) => {
 	// Placeholders
 	//
 	// [fullhash] - data.hash (3a4b5c6e7f)
+	// [index] - data.index (14)
 	//
 	// Legacy Placeholders
 	//
@@ -171,6 +172,9 @@ const replacePathVariables = (path, data, assetInfo) => {
 			)
 		);
 	}
+	if (data.index) {
+		replacements.set("index", replacer(data.index));
+	}
 
 	// Chunk Context
 	//

lib/config/defaults.js

@@ -808,9 +808,17 @@ const applyOutputDefaults = (
 	D(
 		output,
 		"hotUpdateChunkFilename",
-		`[id].[fullhash].hot-update.${output.module ? "mjs" : "js"}`
+		futureDefaults
+			? `[id].[index].hot-update.${output.module ? "mjs" : "js"}`
+			: `[id].[fullhash].hot-update.${output.module ? "mjs" : "js"}`
+	);
+	D(
+		output,
+		"hotUpdateMainFilename",
+		futureDefaults
+			? "[runtime].[index].hot-update.json"
+			: "[runtime].[fullhash].hot-update.json"
 	);
-	D(output, "hotUpdateMainFilename", "[runtime].[fullhash].hot-update.json");
 	D(output, "crossOriginLoading", false);
 	F(output, "scriptType", () => (output.module ? "module" : false));
 	D(

lib/hmr/HotModuleReplacement.runtime.js

@@ -8,6 +8,10 @@
 var $interceptModuleExecution$ = undefined;
 var $moduleCache$ = undefined;
 // eslint-disable-next-line no-unused-vars
+var $getFullHash$ = undefined;
+// eslint-disable-next-line no-unused-vars
+var $compilationIndex$ = undefined;
+// eslint-disable-next-line no-unused-vars
 var $hmrModuleData$ = undefined;
 /** @type {() => Promise}  */
 var $hmrDownloadManifest$ = undefined;
@@ -26,12 +30,15 @@ module.exports = function () {
 	// status
 	var registeredStatusHandlers = [];
 	var currentStatus = "idle";
+	var additionalUpdate = false;
 
 	// while downloading
 	var blockingPromises;
 
 	// The update info
 	var currentUpdateApplyHandlers;
+	var currentUpdateCompilationIndex;
+	var currentUpdateCompilationHash;
 	var queuedInvalidatedModules;
 
 	// eslint-disable-next-line no-unused-vars
@@ -200,6 +207,12 @@ module.exports = function () {
 				var idx = registeredStatusHandlers.indexOf(l);
 				if (idx >= 0) registeredStatusHandlers.splice(idx, 1);
 			},
+			getUpdateIndex: function () {
+				return currentUpdateCompilationIndex;
+			},
+			getUpdateHash: function () {
+				return currentUpdateCompilationHash;
+			},
 
 			//inherit from previous dispose call
 			data: currentModuleData[moduleId]
@@ -230,6 +243,9 @@ module.exports = function () {
 			case "prepare":
 				blockingPromises.push(promise);
 				return promise;
+			case "check":
+				if (additionalUpdate) blockingPromises.push(promise);
+				return promise;
 			default:
 				return promise;
 		}
@@ -244,25 +260,51 @@ module.exports = function () {
 		});
 	}
 
-	function hotCheck(applyOnUpdate) {
+	function applyOutOfBandInfo() {
-		if (currentStatus !== "idle") {
+		if (currentUpdateCompilationIndex !== undefined) {
-			throw new Error("check() is only allowed in idle status");
+			$compilationIndex$ = currentUpdateCompilationIndex;
+			currentUpdateCompilationIndex = undefined;
 		}
+		if (currentUpdateCompilationHash !== undefined) {
+			var value = currentUpdateCompilationHash;
+			$getFullHash$ = function () {
+				return value;
+			};
+			currentUpdateCompilationHash = undefined;
+		}
+	}
+
+	function hotCheck(applyOnUpdate) {
+		if (currentStatus !== "idle" && currentStatus !== "ready") {
+			throw new Error("check() is only allowed in idle or ready status");
+		}
+		additionalUpdate = currentStatus === "ready";
+		// apply outstanding compilation index update to get the new hot update files
+		applyOutOfBandInfo();
 		return setStatus("check")
 			.then($hmrDownloadManifest$)
 			.then(function (update) {
 				if (!update) {
-					return setStatus(applyInvalidatedModules() ? "ready" : "idle").then(
+					return waitForBlockingPromises(function () {
+						additionalUpdate = applyInvalidatedModules() || additionalUpdate;
+						if (additionalUpdate && applyOnUpdate) {
+							return internalApply(applyOnUpdate);
+						} else {
+							return setStatus(additionalUpdate ? "ready" : "idle").then(
 								function () {
 									return null;
 								}
 							);
 						}
+					});
+				}
 
 				return setStatus("prepare").then(function () {
 					var updatedModules = [];
 					blockingPromises = [];
-					currentUpdateApplyHandlers = [];
+					if (!currentUpdateApplyHandlers) currentUpdateApplyHandlers = [];
+					currentUpdateCompilationIndex = update.n;
+					currentUpdateCompilationHash = update.h;
 
 					return Promise.all(
 						Object.keys($hmrDownloadUpdateHandlers$).reduce(function (
@@ -308,6 +350,7 @@ module.exports = function () {
 		options = options || {};
 
 		applyInvalidatedModules();
+		applyOutOfBandInfo();
 
 		var results = currentUpdateApplyHandlers.map(function (handler) {
 			return handler(options);

lib/hmr/HotModuleReplacementRuntimeModule.js

@@ -21,6 +21,7 @@ class HotModuleReplacementRuntimeModule extends RuntimeModule {
 			require("./HotModuleReplacement.runtime.js")
 		)
 			.replace(/\$getFullHash\$/g, RuntimeGlobals.getFullHash)
+			.replace(/\$compilationIndex\$/g, RuntimeGlobals.compilationIndex)
 			.replace(
 				/\$interceptModuleExecution\$/g,
 				RuntimeGlobals.interceptModuleExecution

lib/hmr/JavascriptHotModuleReplacement.runtime.js

@@ -295,6 +295,7 @@ module.exports = function () {
 				for (var i = 0; i < currentUpdateRuntime.length; i++) {
 					currentUpdateRuntime[i](__webpack_require__);
 				}
+				currentUpdateRuntime = undefined;
 
 				// call accept handlers
 				for (var outdatedModuleId in outdatedDependencies) {
@@ -428,14 +429,20 @@ module.exports = function () {
 		applyHandlers,
 		updatedModulesList
 	) {
-		applyHandlers.push(applyHandler);
+		if (!currentUpdate) {
-		currentUpdateChunks = {};
+			currentUpdate = {};
-		currentUpdateRemovedChunks = removedChunks;
-		currentUpdate = removedModules.reduce(function (obj, key) {
-			obj[key] = false;
-			return obj;
-		}, {});
 			currentUpdateRuntime = [];
+			currentUpdateRemovedChunks = [];
+			applyHandlers.push(applyHandler);
+		}
+		currentUpdateChunks = {};
+		currentUpdateRemovedChunks.push.apply(
+			currentUpdateRemovedChunks,
+			removedChunks
+		);
+		removedModules.forEach(function (key) {
+			currentUpdate[key] = false;
+		});
 		chunkIds.forEach(function (chunkId) {
 			if (
 				$hasOwnProperty$($installedChunks$, chunkId) &&

lib/javascript/JavascriptModulesPlugin.js

@@ -231,6 +231,7 @@ class JavascriptModulesPlugin {
 					"JavascriptModulesPlugin",
 					(result, options) => {
 						const {
+							index,
 							hash,
 							chunk,
 							chunkGraph,
@@ -305,6 +306,7 @@ class JavascriptModulesPlugin {
 							filenameTemplate,
 							pathOptions: {
 								hash,
+								index,
 								runtime: chunk.runtime,
 								chunk,
 								contentHashType: "javascript"

lib/runtime/CompilationIndexRuntimeModule.js

@@ -0,0 +1,27 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+*/
+
+"use strict";
+
+const RuntimeGlobals = require("../RuntimeGlobals");
+const RuntimeModule = require("../RuntimeModule");
+
+class CompilationIndexRuntimeModule extends RuntimeModule {
+	/**
+	 * @param {number} compilationIndex the compilation index
+	 */
+	constructor(compilationIndex) {
+		super("compilation index");
+		this.compilationIndex = compilationIndex;
+	}
+
+	/**
+	 * @returns {string} runtime code
+	 */
+	generate() {
+		return `${RuntimeGlobals.compilationIndex} = ${this.compilationIndex};`;
+	}
+}
+
+module.exports = CompilationIndexRuntimeModule;

lib/runtime/GetChunkFilenameRuntimeModule.js

@@ -144,6 +144,7 @@ class GetChunkFilenameRuntimeModule extends RuntimeModule {
 					  )
 					: JSON.stringify(chunkFilename);
 			const staticChunkFilename = compilation.getPath(chunkFilenameValue, {
+				index: `" + ${RuntimeGlobals.compilationIndex} + "`,
 				hash: `" + ${RuntimeGlobals.getFullHash}() + "`,
 				hashWithLength: length =>
 					`" + ${RuntimeGlobals.getFullHash}().slice(0, ${length}) + "`,
@@ -229,6 +230,7 @@ class GetChunkFilenameRuntimeModule extends RuntimeModule {
 		const url =
 			dynamicFilename &&
 			compilation.getPath(JSON.stringify(dynamicFilename), {
+				index: `" + ${RuntimeGlobals.compilationIndex} + "`,
 				hash: `" + ${RuntimeGlobals.getFullHash}() + "`,
 				hashWithLength: length =>
 					`" + ${RuntimeGlobals.getFullHash}().slice(0, ${length}) + "`,

lib/runtime/GetMainFilenameRuntimeModule.js

@@ -29,6 +29,7 @@ class GetMainFilenameRuntimeModule extends RuntimeModule {
 		const { global, filename, compilation, chunk } = this;
 		const { runtimeTemplate } = compilation;
 		const url = compilation.getPath(JSON.stringify(filename), {
+			index: `" + ${RuntimeGlobals.compilationIndex} + "`,
 			hash: `" + ${RuntimeGlobals.getFullHash}() + "`,
 			hashWithLength: length =>
 				`" + ${RuntimeGlobals.getFullHash}().slice(0, ${length}) + "`,

lib/wasm-async/AsyncWasmLoadingRuntimeModule.js

@@ -26,6 +26,7 @@ class AsyncWasmLoadingRuntimeModule extends RuntimeModule {
 		const wasmModuleSrcPath = compilation.getPath(
 			JSON.stringify(outputOptions.webassemblyModuleFilename),
 			{
+				index: `" + ${RuntimeGlobals.compilationIndex} + "`,
 				hash: `" + ${RuntimeGlobals.getFullHash}() + "`,
 				hashWithLength: length =>
 					`" + ${RuntimeGlobals.getFullHash}}().slice(0, ${length}) + "`,

lib/wasm-sync/WasmChunkLoadingRuntimeModule.js

@@ -233,6 +233,7 @@ class WasmChunkLoadingRuntimeModule extends RuntimeModule {
 		const wasmModuleSrcPath = compilation.getPath(
 			JSON.stringify(outputOptions.webassemblyModuleFilename),
 			{
+				index: `" + ${RuntimeGlobals.compilationIndex} + "`,
 				hash: `" + ${RuntimeGlobals.getFullHash}() + "`,
 				hashWithLength: length =>
 					`" + ${RuntimeGlobals.getFullHash}}().slice(0, ${length}) + "`,

lib/web/JsonpChunkLoadingRuntimeModule.js

@@ -274,9 +274,8 @@ class JsonpChunkLoadingRuntimeModule extends RuntimeModule {
 			"",
 			withHmr
 				? Template.asString([
-						"var currentUpdatedModulesList;",
 						"var waitingUpdateResolves = {};",
-						"function loadUpdateChunk(chunkId) {",
+						"function loadUpdateChunk(chunkId, updatedModulesList) {",
 						Template.indent([
 							`return new Promise(${runtimeTemplate.basicFunction(
 								"resolve, reject",
@@ -302,6 +301,9 @@ class JsonpChunkLoadingRuntimeModule extends RuntimeModule {
 									])};`,
 									`${RuntimeGlobals.loadScript}(url, loadingEnded);`
 								]
+							)}).then(${runtimeTemplate.basicFunction(
+								"updatedModules",
+								"if(updatedModulesList) updatedModulesList.push.apply(updatedModulesList, updatedModules);"
 							)});`
 						]),
 						"}",
@@ -311,12 +313,13 @@ class JsonpChunkLoadingRuntimeModule extends RuntimeModule {
 						)}] = ${runtimeTemplate.basicFunction(
 							"chunkId, moreModules, runtime",
 							[
+								"var updatedModules = [];",
 								"for(var moduleId in moreModules) {",
 								Template.indent([
 									`if(${RuntimeGlobals.hasOwnProperty}(moreModules, moduleId)) {`,
 									Template.indent([
 										"currentUpdate[moduleId] = moreModules[moduleId];",
-										"if(currentUpdatedModulesList) currentUpdatedModulesList.push(moduleId);"
+										"updatedModules.push(moduleId);"
 									]),
 									"}"
 								]),
@@ -324,7 +327,7 @@ class JsonpChunkLoadingRuntimeModule extends RuntimeModule {
 								"if(runtime) currentUpdateRuntime.push(runtime);",
 								"if(waitingUpdateResolves[chunkId]) {",
 								Template.indent([
-									"waitingUpdateResolves[chunkId]();",
+									"waitingUpdateResolves[chunkId](updatedModules);",
 									"waitingUpdateResolves[chunkId] = undefined;"
 								]),
 								"}"

test/hotCases/merge-updates/simple/errors1.js

@@ -0,0 +1 @@
+module.exports = [[/Module parse failed/]];

test/hotCases/merge-updates/simple/index.js

@@ -0,0 +1,34 @@
+import value from "./module";
+import value2 from "./module2";
+
+import.meta.webpackHot.accept("./module");
+import.meta.webpackHot.accept("./module2");
+
+it("should merge multiple updates when not using apply", done => {
+	expect(value).toBe(42);
+	expect(value2).toBe(42);
+	NEXT(err => {
+		if (err) return done(err);
+		NEXT(err => {
+			if (err) return done(err);
+			module.hot
+				.check()
+				.then(updatedModules => {
+					expect(updatedModules).toEqual(["./module.js", "./module2.js"]);
+					return module.hot.check(true).then(updatedModules => {
+						expect(updatedModules).toEqual(["./module.js", "./module2.js"]);
+						try {
+							expect(value).toBe(43);
+							expect(value2).toBe(43);
+						} catch (e) {
+							return done(e);
+						}
+						done();
+					});
+				})
+				.catch(err => {
+					done(err);
+				});
+		});
+	});
+});

test/hotCases/merge-updates/simple/module.js

@@ -0,0 +1,6 @@
+export default 42;
+---
+throw new Error("Invalid")
+export default 0;
+---
+export default 43

test/hotCases/merge-updates/simple/module2.js

@@ -0,0 +1,6 @@
+export default 42;
+---
+}}}
+export default 0;
+---
+export default 43

types.d.ts

@@ -1424,7 +1424,7 @@ declare class Compilation {
 		chunkHash: SyncHook<[Chunk, Hash, ChunkHashContext]>;
 		moduleAsset: SyncHook<[Module, string]>;
 		chunkAsset: SyncHook<[Chunk, string]>;
-		assetPath: SyncWaterfallHook<[string, object, AssetInfo]>;
+		assetPath: SyncWaterfallHook<[string, PathData, AssetInfo]>;
 		needAdditionalPass: SyncBailHook<[], boolean>;
 		childCompiler: SyncHook<[Compiler, string, number]>;
 		log: SyncBailHook<[string, LogEntry], true>;
@@ -1491,6 +1491,9 @@ declare class Compilation {
 	namedChunks: Map<string, Chunk>;
 	modules: Set<Module>;
 	records: any;
+	hash?: string;
+	fullHash?: string;
+	index?: number;
 	additionalChunkAssets: string[];
 	assets: CompilationAssets;
 	assetsInfo: Map<string, AssetInfo>;
@@ -1667,8 +1670,6 @@ declare class Compilation {
 		runtime: RuntimeSpec;
 		runtimes: RuntimeSpec[];
 	}[];
-	fullHash?: string;
-	hash?: string;
 	emitAsset(file: string, source: Source, assetInfo?: AssetInfo): void;
 	updateAsset(
 		file: string,
@@ -8611,6 +8612,7 @@ declare interface ParserStateBase {
 declare interface PathData {
 	chunkGraph?: ChunkGraph;
 	hash?: string;
+	index?: string;
 	hashWithLength?: (arg0: number) => string;
 	chunk?: Chunk | ChunkPathData;
 	module?: Module | ModulePathData;
@@ -9056,6 +9058,7 @@ declare interface RenderManifestOptions {
 	 * the chunk used to render
 	 */
 	chunk: Chunk;
+	index: string;
 	hash: string;
 	fullHash: string;
 	outputOptions: Output;
@@ -11419,7 +11422,7 @@ declare interface UpdateHashContextGenerator {
 	chunkGraph: ChunkGraph;
 	runtime: RuntimeSpec;
 }
-type UsageStateType = 0 | 1 | 2 | 3 | 4;
+type UsageStateType = 0 | 2 | 3 | 1 | 4;
 declare interface UserResolveOptions {
 	/**
 	 * A list of module alias configurations or an object which maps key to value
@@ -12179,6 +12182,7 @@ declare namespace exports {
 		export let harmonyModuleDecorator: string;
 		export let nodeModuleDecorator: string;
 		export let getFullHash: string;
+		export let compilationIndex: string;
 		export let wasmInstances: string;
 		export let instantiateWasm: string;
 		export let uncaughtErrorHandler: string;