webpack/lib/optimize/ConcatenatedModule.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const eslintScope = require("eslint-scope");
const {
	CachedSource,
	ConcatSource,
	ReplaceSource
} = require("webpack-sources");
const ConcatenationScope = require("../ConcatenationScope");
const { UsageState } = require("../ExportsInfo");
const Module = require("../Module");
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const HarmonyImportDependency = require("../dependencies/HarmonyImportDependency");
const JavascriptParser = require("../javascript/JavascriptParser");
const { equals } = require("../util/ArrayHelpers");
const LazySet = require("../util/LazySet");
const { concatComparators, keepOriginalOrder } = require("../util/comparators");
const createHash = require("../util/createHash");
const contextify = require("../util/identifier").contextify;
const makeSerializable = require("../util/makeSerializable");
const propertyAccess = require("../util/propertyAccess");

/** @typedef {import("eslint-scope").Scope} Scope */
/** @typedef {import("webpack-sources").Source} Source */
/** @typedef {import("../../declarations/WebpackOptions").WebpackOptionsNormalized} WebpackOptions */
/** @typedef {import("../ChunkGraph")} ChunkGraph */
/** @typedef {import("../Compilation")} Compilation */
/** @typedef {import("../Dependency")} Dependency */
/** @typedef {import("../Dependency").UpdateHashContext} UpdateHashContext */
/** @typedef {import("../DependencyTemplate").DependencyTemplateContext} DependencyTemplateContext */
/** @typedef {import("../DependencyTemplates")} DependencyTemplates */
/** @typedef {import("../ExportsInfo").ExportInfo} ExportInfo */
/** @typedef {import("../Module").CodeGenerationContext} CodeGenerationContext */
/** @typedef {import("../Module").CodeGenerationResult} CodeGenerationResult */
/** @typedef {import("../Module").LibIdentOptions} LibIdentOptions */
/** @typedef {import("../ModuleGraph")} ModuleGraph */
/** @typedef {import("../ModuleGraphConnection")} ModuleGraphConnection */
/** @typedef {import("../RequestShortener")} RequestShortener */
/** @typedef {import("../ResolverFactory").ResolverWithOptions} ResolverWithOptions */
/** @typedef {import("../RuntimeTemplate")} RuntimeTemplate */
/** @typedef {import("../WebpackError")} WebpackError */
/** @typedef {import("../util/Hash")} Hash */
/** @typedef {import("../util/fs").InputFileSystem} InputFileSystem */
/** @typedef {import("../util/runtime").RuntimeSpec} RuntimeSpec */

/**
 * @typedef {Object} ReexportInfo
 * @property {Module} module
 * @property {string[]} export
 */

/** @typedef {RawBinding | SymbolBinding} Binding */

/**
 * @typedef {Object} RawBinding
 * @property {ModuleInfo} info
 * @property {string} rawName
 * @property {string=} comment
 * @property {string[]} ids
 * @property {string[]} exportName
 */

/**
 * @typedef {Object} SymbolBinding
 * @property {ConcatenatedModuleInfo} info
 * @property {string} name
 * @property {string=} comment
 * @property {string[]} ids
 * @property {string[]} exportName
 */

/** @typedef {ConcatenatedModuleInfo | ExternalModuleInfo } ModuleInfo */

/**
 * @typedef {Object} ConcatenatedModuleInfo
 * @property {"concatenated"} type
 * @property {Module} module
 * @property {number} index
 * @property {Object} ast
 * @property {Source} internalSource
 * @property {ReplaceSource} source
 * @property {Iterable<string>} runtimeRequirements
 * @property {Scope} globalScope
 * @property {Scope} moduleScope
 * @property {Map<string, string>} internalNames
 * @property {Map<string, string>} exportMap
 * @property {Map<string, string>} rawExportMap
 * @property {string=} namespaceExportSymbol
 * @property {string} namespaceObjectName
 * @property {boolean} interopNamespaceObjectUsed
 * @property {string} interopNamespaceObjectName
 * @property {boolean} interopDefaultAccessUsed
 * @property {string} interopDefaultAccessName
 */

/**
 * @typedef {Object} ExternalModuleInfo
 * @property {"external"} type
 * @property {Module} module
 * @property {number} index
 * @property {string} name
 * @property {boolean} interopNamespaceObjectUsed
 * @property {string} interopNamespaceObjectName
 * @property {boolean} interopDefaultAccessUsed
 * @property {string} interopDefaultAccessName
 */

const RESERVED_NAMES = [
	// internal names (should always be renamed)
	ConcatenationScope.DEFAULT_EXPORT,
	ConcatenationScope.NAMESPACE_OBJECT_EXPORT,

	// keywords
	"abstract,arguments,async,await,boolean,break,byte,case,catch,char,class,const,continue",
	"debugger,default,delete,do,double,else,enum,eval,export,extends,false,final,finally,float",
	"for,function,goto,if,implements,import,in,instanceof,int,interface,let,long,native,new,null",
	"package,private,protected,public,return,short,static,super,switch,synchronized,this,throw",
	"throws,transient,true,try,typeof,var,void,volatile,while,with,yield",

	// commonjs
	"module,__dirname,__filename,exports",

	// js globals
	"Array,Date,eval,function,hasOwnProperty,Infinity,isFinite,isNaN,isPrototypeOf,length,Math",
	"NaN,name,Number,Object,prototype,String,toString,undefined,valueOf",

	// browser globals
	"alert,all,anchor,anchors,area,assign,blur,button,checkbox,clearInterval,clearTimeout",
	"clientInformation,close,closed,confirm,constructor,crypto,decodeURI,decodeURIComponent",
	"defaultStatus,document,element,elements,embed,embeds,encodeURI,encodeURIComponent,escape",
	"event,fileUpload,focus,form,forms,frame,innerHeight,innerWidth,layer,layers,link,location",
	"mimeTypes,navigate,navigator,frames,frameRate,hidden,history,image,images,offscreenBuffering",
	"open,opener,option,outerHeight,outerWidth,packages,pageXOffset,pageYOffset,parent,parseFloat",
	"parseInt,password,pkcs11,plugin,prompt,propertyIsEnum,radio,reset,screenX,screenY,scroll",
	"secure,select,self,setInterval,setTimeout,status,submit,taint,text,textarea,top,unescape",
	"untaint,window",

	// window events
	"onblur,onclick,onerror,onfocus,onkeydown,onkeypress,onkeyup,onmouseover,onload,onmouseup,onmousedown,onsubmit"
]
	.join(",")
	.split(",");

const bySourceOrder = (a, b) => {
	const aOrder = a.sourceOrder;
	const bOrder = b.sourceOrder;
	if (isNaN(aOrder)) {
		if (!isNaN(bOrder)) {
			return 1;
		}
	} else {
		if (isNaN(bOrder)) {
			return -1;
		}
		if (aOrder !== bOrder) {
			return aOrder < bOrder ? -1 : 1;
		}
	}
	return 0;
};

const joinIterableWithComma = iterable => {
	// This is more performant than Array.from().join(", ")
	// as it doesn't create an array
	let str = "";
	let first = true;
	for (const item of iterable) {
		if (first) {
			first = false;
		} else {
			str += ", ";
		}
		str += item;
	}
	return str;
};

/**
 * @typedef {Object} ConcatenationEntry
 * @property {"concatenated" | "external"} type
 * @property {Module} module
 */

/**
 * @param {ModuleGraph} moduleGraph the module graph
 * @param {ModuleInfo} info module info
 * @param {string[]} exportName exportName
 * @param {Map<Module, ModuleInfo>} moduleToInfoMap moduleToInfoMap
 * @param {RuntimeSpec} runtime for which runtime
 * @param {RequestShortener} requestShortener the request shortener
 * @param {RuntimeTemplate} runtimeTemplate the runtime template
 * @param {Set<ConcatenatedModuleInfo>} neededNamespaceObjects modules for which a namespace object should be generated
 * @param {boolean} asCall asCall
 * @param {boolean} strictHarmonyModule strictHarmonyModule
 * @param {boolean | undefined} asiSafe asiSafe
 * @param {Set<ExportInfo>} alreadyVisited alreadyVisited
 * @returns {Binding} the final variable
 */
const getFinalBinding = (
	moduleGraph,
	info,
	exportName,
	moduleToInfoMap,
	runtime,
	requestShortener,
	runtimeTemplate,
	neededNamespaceObjects,
	asCall,
	strictHarmonyModule,
	asiSafe,
	alreadyVisited = new Set()
) => {
	const exportsType = info.module.getExportsType(
		moduleGraph,
		strictHarmonyModule
	);
	if (exportName.length === 0) {
		switch (exportsType) {
			case "default-only":
			case "default-with-named":
				info.interopNamespaceObjectUsed = true;
				return {
					info,
					rawName: info.interopNamespaceObjectName,
					ids: exportName,
					exportName
				};
			case "namespace":
			case "dynamic":
				break;
			default:
				throw new Error(`Unexpected exportsType ${exportsType}`);
		}
	} else {
		switch (exportsType) {
			case "namespace":
				break;
			case "default-with-named":
				if (exportName[0] === "default") {
					exportName = exportName.slice(1);
				}
				break;
			case "default-only": {
				const exportId = exportName[0];
				exportName = exportName.slice(1);
				if (exportId !== "default") {
					return {
						info,
						rawName:
							"/* non-default import from default-exporting module */undefined",
						ids: exportName,
						exportName
					};
				}
				break;
			}
			case "dynamic":
				if (exportName[0] === "default") {
					exportName = exportName.slice(1);
					info.interopDefaultAccessUsed = true;
					const defaultExport = asCall
						? `${info.interopDefaultAccessName}()`
						: asiSafe
						? `(${info.interopDefaultAccessName}())`
						: asiSafe === false
						? `;(${info.interopDefaultAccessName}())`
						: `${info.interopDefaultAccessName}.a`;
					return {
						info,
						rawName: defaultExport,
						ids: exportName,
						exportName
					};
				}
				break;
			default:
				throw new Error(`Unexpected exportsType ${exportsType}`);
		}
	}
	if (exportName.length === 0) {
		switch (info.type) {
			case "concatenated":
				neededNamespaceObjects.add(info);
				return {
					info,
					rawName: info.namespaceObjectName,
					ids: exportName,
					exportName
				};
			case "external":
				return { info, rawName: info.name, ids: exportName, exportName };
		}
	}
	const exportsInfo = moduleGraph.getExportsInfo(info.module);
	const exportInfo = exportsInfo.getExportInfo(exportName[0]);
	if (alreadyVisited.has(exportInfo)) {
		return {
			info,
			rawName: "/* circular reexport */ Object(function x() { x() }())",
			ids: [],
			exportName
		};
	}
	alreadyVisited.add(exportInfo);
	if (exportInfo.getUsed(runtime) === UsageState.Unused) {
		return {
			info,
			rawName: "/* unused export */ undefined",
			ids: exportName.slice(1),
			exportName
		};
	}
	switch (info.type) {
		case "concatenated": {
			const exportId = exportName[0];
			if (exportInfo.provided === false) {
				// It's not provided, but it could be on the prototype
				neededNamespaceObjects.add(info);
				return {
					info,
					rawName: info.namespaceObjectName,
					ids: exportName,
					exportName
				};
			}
			const directExport = info.exportMap && info.exportMap.get(exportId);
			if (directExport) {
				const usedName = /** @type {string[]} */ (exportsInfo.getUsedName(
					exportName,
					runtime
				));
				return {
					info,
					name: directExport,
					ids: usedName.slice(1),
					exportName
				};
			}
			const rawExport = info.rawExportMap && info.rawExportMap.get(exportId);
			if (rawExport) {
				return {
					info,
					rawName: rawExport,
					ids: exportName.slice(1),
					exportName
				};
			}
			const reexport = exportInfo.findTarget(moduleGraph, module =>
				moduleToInfoMap.has(module)
			);
			if (reexport === false) {
				throw new Error(
					`Target module of reexport from '${info.module.readableIdentifier(
						requestShortener
					)}' is not part of the concatenation`
				);
			}
			if (reexport) {
				const refInfo = moduleToInfoMap.get(reexport.module);
				return getFinalBinding(
					moduleGraph,
					refInfo,
					reexport.export
						? [...reexport.export, ...exportName.slice(1)]
						: exportName.slice(1),
					moduleToInfoMap,
					runtime,
					requestShortener,
					runtimeTemplate,
					neededNamespaceObjects,
					asCall,
					info.module.buildMeta.strictHarmonyModule,
					asiSafe,
					alreadyVisited
				);
			}
			if (info.namespaceExportSymbol) {
				const usedName = /** @type {string[]} */ (exportsInfo.getUsedName(
					exportName,
					runtime
				));
				return {
					info,
					rawName: info.namespaceObjectName,
					ids: usedName,
					exportName
				};
			}
			throw new Error(
				`Cannot get final name for export '${exportName.join(
					"."
				)}' of ${info.module.readableIdentifier(requestShortener)}`
			);
		}

		case "external": {
			const used = /** @type {string[]} */ (exportsInfo.getUsedName(
				exportName,
				runtime
			));
			const comment = equals(used, exportName)
				? ""
				: Template.toNormalComment(`${exportName.join(".")}`);
			return { info, rawName: info.name + comment, ids: used, exportName };
		}
	}
};

/**
 * @param {ModuleGraph} moduleGraph the module graph
 * @param {ModuleInfo} info module info
 * @param {string[]} exportName exportName
 * @param {Map<Module, ModuleInfo>} moduleToInfoMap moduleToInfoMap
 * @param {RuntimeSpec} runtime for which runtime
 * @param {RequestShortener} requestShortener the request shortener
 * @param {RuntimeTemplate} runtimeTemplate the runtime template
 * @param {Set<ConcatenatedModuleInfo>} neededNamespaceObjects modules for which a namespace object should be generated
 * @param {boolean} asCall asCall
 * @param {boolean} callContext callContext
 * @param {boolean} strictHarmonyModule strictHarmonyModule
 * @param {boolean | undefined} asiSafe asiSafe
 * @returns {string} the final name
 */
const getFinalName = (
	moduleGraph,
	info,
	exportName,
	moduleToInfoMap,
	runtime,
	requestShortener,
	runtimeTemplate,
	neededNamespaceObjects,
	asCall,
	callContext,
	strictHarmonyModule,
	asiSafe
) => {
	const binding = getFinalBinding(
		moduleGraph,
		info,
		exportName,
		moduleToInfoMap,
		runtime,
		requestShortener,
		runtimeTemplate,
		neededNamespaceObjects,
		asCall,
		strictHarmonyModule,
		asiSafe
	);
	{
		const { ids, comment } = binding;
		let reference;
		let isPropertyAccess;
		if ("rawName" in binding) {
			reference = `${binding.rawName}${comment || ""}${propertyAccess(ids)}`;
			isPropertyAccess = ids.length > 0;
		} else {
			const { info, name: exportId } = binding;
			const name = info.internalNames.get(exportId);
			if (!name) {
				throw new Error(
					`The export "${exportId}" in "${info.module.readableIdentifier(
						requestShortener
					)}" has no internal name (existing names: ${
						Array.from(
							info.internalNames,
							([name, symbol]) => `${name}: ${symbol}`
						).join(", ") || "none"
					})`
				);
			}
			reference = `${name}${comment || ""}${propertyAccess(ids)}`;
			isPropertyAccess = ids.length > 1;
		}
		if (isPropertyAccess && asCall && callContext === false) {
			return asiSafe
				? `(0,${reference})`
				: asiSafe === false
				? `;(0,${reference})`
				: `Object(${reference})`;
		}
		return reference;
	}
};

const addScopeSymbols = (s, nameSet, scopeSet1, scopeSet2) => {
	let scope = s;
	while (scope) {
		if (scopeSet1.has(scope)) break;
		if (scopeSet2.has(scope)) break;
		scopeSet1.add(scope);
		for (const variable of scope.variables) {
			nameSet.add(variable.name);
		}
		scope = scope.upper;
	}
};

const getAllReferences = variable => {
	let set = variable.references;
	// Look for inner scope variables too (like in class Foo { t() { Foo } })
	const identifiers = new Set(variable.identifiers);
	for (const scope of variable.scope.childScopes) {
		for (const innerVar of scope.variables) {
			if (innerVar.identifiers.some(id => identifiers.has(id))) {
				set = set.concat(innerVar.references);
				break;
			}
		}
	}
	return set;
};

const getPathInAst = (ast, node) => {
	if (ast === node) {
		return [];
	}

	const nr = node.range;

	const enterNode = n => {
		if (!n) return undefined;
		const r = n.range;
		if (r) {
			if (r[0] <= nr[0] && r[1] >= nr[1]) {
				const path = getPathInAst(n, node);
				if (path) {
					path.push(n);
					return path;
				}
			}
		}
		return undefined;
	};

	if (Array.isArray(ast)) {
		for (let i = 0; i < ast.length; i++) {
			const enterResult = enterNode(ast[i]);
			if (enterResult !== undefined) return enterResult;
		}
	} else if (ast && typeof ast === "object") {
		const keys = Object.keys(ast);
		for (let i = 0; i < keys.length; i++) {
			const value = ast[keys[i]];
			if (Array.isArray(value)) {
				const pathResult = getPathInAst(value, node);
				if (pathResult !== undefined) return pathResult;
			} else if (value && typeof value === "object") {
				const enterResult = enterNode(value);
				if (enterResult !== undefined) return enterResult;
			}
		}
	}
};

/**
 * @param {ModuleInfo[]} modulesWithInfo modules
 * @returns {Map<Module, ModuleInfo>} mapping
 */
const modulesWithInfoToMap = modulesWithInfo => {
	const moduleToInfoMap = new Map();
	for (const m of modulesWithInfo) {
		moduleToInfoMap.set(m.module, m);
	}
	return moduleToInfoMap;
};

const TYPES = new Set(["javascript"]);

class ConcatenatedModule extends Module {
	/**
	 * @param {Module} rootModule the root module of the concatenation
	 * @param {Set<Module>} modules all modules in the concatenation (including the root module)
	 * @param {Object=} associatedObjectForCache object for caching
	 * @returns {ConcatenatedModule} the module
	 */
	static create(rootModule, modules, associatedObjectForCache) {
		const identifier = ConcatenatedModule._createIdentifier(
			rootModule,
			modules,
			associatedObjectForCache
		);
		return new ConcatenatedModule({
			identifier,
			rootModule,
			modules
		});
	}

	/**
	 * @param {Object} options options
	 * @param {string} options.identifier the identifier of the module
	 * @param {Module=} options.rootModule the root module of the concatenation
	 * @param {Set<Module>=} options.modules all concatenated modules
	 */
	constructor({ identifier, rootModule, modules }) {
		super("javascript/esm", null);

		// Info from Factory
		/** @type {string} */
		this._identifier = identifier;
		/** @type {Module} */
		this.rootModule = rootModule;
		/** @type {Set<Module>} */
		this._modules = modules;
		this.factoryMeta = rootModule && rootModule.factoryMeta;

		// Caching
		// TODO
	}

	/**
	 * Assuming this module is in the cache. Update the (cached) module with
	 * the fresh module from the factory. Usually updates internal references
	 * and properties.
	 * @param {Module} module fresh module
	 * @returns {void}
	 */
	updateCacheModule(module) {
		super.updateCacheModule(module);
		const m = /** @type {ConcatenatedModule} */ (module);
		this._identifier = m._identifier;
		this.rootModule = m.rootModule;
		this._modules = m._modules;
	}
	/**
	 * @returns {Set<string>} types available (do not mutate)
	 */
	getSourceTypes() {
		return TYPES;
	}

	get modules() {
		return Array.from(this._modules);
	}

	/**
	 * @returns {string} a unique identifier of the module
	 */
	identifier() {
		return this._identifier;
	}

	/**
	 * @param {RequestShortener} requestShortener the request shortener
	 * @returns {string} a user readable identifier of the module
	 */
	readableIdentifier(requestShortener) {
		return (
			this.rootModule.readableIdentifier(requestShortener) +
			` + ${this._modules.size - 1} modules`
		);
	}

	/**
	 * @param {LibIdentOptions} options options
	 * @returns {string | null} an identifier for library inclusion
	 */
	libIdent(options) {
		return this.rootModule.libIdent(options);
	}

	/**
	 * @returns {string | null} absolute path which should be used for condition matching (usually the resource path)
	 */
	nameForCondition() {
		return this.rootModule.nameForCondition();
	}

	/**
	 * @param {WebpackOptions} options webpack options
	 * @param {Compilation} compilation the compilation
	 * @param {ResolverWithOptions} resolver the resolver
	 * @param {InputFileSystem} fs the file system
	 * @param {function(WebpackError=): void} callback callback function
	 * @returns {void}
	 */
	build(options, compilation, resolver, fs, callback) {
		const { rootModule } = this;
		this.buildInfo = {
			strict: true,
			cacheable: true,
			moduleArgument: rootModule.buildInfo.moduleArgument,
			exportsArgument: rootModule.buildInfo.exportsArgument,
			fileDependencies: new LazySet(),
			contextDependencies: new LazySet(),
			missingDependencies: new LazySet(),
			assets: undefined
		};
		this.buildMeta = rootModule.buildMeta;
		this.clearDependenciesAndBlocks();
		this.clearWarningsAndErrors();

		for (const m of this._modules) {
			// populate cacheable
			if (!m.buildInfo.cacheable) {
				this.buildInfo.cacheable = false;
			}

			// populate dependencies
			for (const d of m.dependencies.filter(
				dep =>
					!(dep instanceof HarmonyImportDependency) ||
					!this._modules.has(compilation.moduleGraph.getModule(dep))
			)) {
				this.dependencies.push(d);
			}
			// populate blocks
			for (const d of m.blocks) {
				this.blocks.push(d);
			}

			// populate warnings
			const warnings = m.getWarnings();
			if (warnings !== undefined) {
				for (const warning of warnings) {
					this.addWarning(warning);
				}
			}

			// populate errors
			const errors = m.getErrors();
			if (errors !== undefined) {
				for (const error of errors) {
					this.addError(error);
				}
			}

			// populate assets
			if (m.buildInfo.assets) {
				if (this.buildInfo.assets === undefined) {
					this.buildInfo.assets = Object.create(null);
				}
				Object.assign(this.buildInfo.assets, m.buildInfo.assets);
			}
			if (m.buildInfo.assetsInfo) {
				if (this.buildInfo.assetsInfo === undefined) {
					this.buildInfo.assetsInfo = new Map();
				}
				for (const [key, value] of m.buildInfo.assetsInfo) {
					this.buildInfo.assetsInfo.set(key, value);
				}
			}
		}
		callback();
	}

	/**
	 * @param {string=} type the source type for which the size should be estimated
	 * @returns {number} the estimated size of the module (must be non-zero)
	 */
	size(type) {
		// Guess size from embedded modules
		let size = 0;
		for (const module of this._modules) {
			size += module.size(type);
		}
		return size;
	}

	/**
	 * @private
	 * @param {Module} rootModule the root of the concatenation
	 * @param {Set<Module>} modulesSet a set of modules which should be concatenated
	 * @param {RuntimeSpec} runtime for this runtime
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @returns {ConcatenationEntry[]} concatenation list
	 */
	_createConcatenationList(rootModule, modulesSet, runtime, moduleGraph) {
		/** @type {ConcatenationEntry[]} */
		const list = [];
		/** @type {Set<Module>} */
		const existingEntries = new Set();

		/**
		 * @param {Module} module a module
		 * @returns {ModuleGraphConnection[]} imported modules in order
		 */
		const getConcatenatedImports = module => {
			let connections = Array.from(moduleGraph.getOutgoingConnections(module));
			if (module === rootModule) {
				for (const c of moduleGraph.getOutgoingConnections(this))
					connections.push(c);
			}
			const references = connections
				.filter(connection => {
					if (!(connection.dependency instanceof HarmonyImportDependency))
						return false;
					return (
						connection &&
						connection.resolvedOriginModule === module &&
						connection.module &&
						connection.isTargetActive(runtime)
					);
				})
				.map(connection => ({
					connection,
					sourceOrder: /** @type {HarmonyImportDependency} */ (connection.dependency)
						.sourceOrder
				}));
			references.sort(
				concatComparators(bySourceOrder, keepOriginalOrder(references))
			);
			return references.map(({ connection }) => connection);
		};

		/**
		 * @param {ModuleGraphConnection} connection graph connection
		 * @returns {void}
		 */
		const enterModule = connection => {
			const module = connection.module;
			if (!module) return;
			if (existingEntries.has(module)) {
				return;
			}
			if (modulesSet.has(module)) {
				existingEntries.add(module);
				const imports = getConcatenatedImports(module);
				imports.forEach(enterModule);
				list.push({
					type: "concatenated",
					module: connection.module
				});
			} else {
				existingEntries.add(connection.module);
				list.push({
					type: "external",
					get module() {
						// We need to use a getter here, because the module in the dependency
						// could be replaced by some other process (i. e. also replaced with a
						// concatenated module)
						return connection.module;
					}
				});
			}
		};

		existingEntries.add(rootModule);
		const imports = getConcatenatedImports(rootModule);
		imports.forEach(enterModule);
		list.push({
			type: "concatenated",
			module: rootModule
		});

		return list;
	}

	static _createIdentifier(rootModule, modules, associatedObjectForCache) {
		const cachedContextify = contextify.bindContextCache(
			rootModule.context,
			associatedObjectForCache
		);
		let identifiers = [];
		for (const module of modules) {
			identifiers.push(cachedContextify(module.identifier()));
		}
		identifiers.sort();
		const hash = createHash("md4");
		hash.update(identifiers.join(" "));
		return rootModule.identifier() + "|" + hash.digest("hex");
	}

	/**
	 * @param {LazySet<string>} fileDependencies set where file dependencies are added to
	 * @param {LazySet<string>} contextDependencies set where context dependencies are added to
	 * @param {LazySet<string>} missingDependencies set where missing dependencies are added to
	 * @param {LazySet<string>} buildDependencies set where build dependencies are added to
	 */
	addCacheDependencies(
		fileDependencies,
		contextDependencies,
		missingDependencies,
		buildDependencies
	) {
		for (const module of this._modules) {
			module.addCacheDependencies(
				fileDependencies,
				contextDependencies,
				missingDependencies,
				buildDependencies
			);
		}
	}

	/**
	 * @param {CodeGenerationContext} context context for code generation
	 * @returns {CodeGenerationResult} result
	 */
	codeGeneration({
		dependencyTemplates,
		runtimeTemplate,
		moduleGraph,
		chunkGraph,
		runtime
	}) {
		/** @type {Set<string>} */
		const runtimeRequirements = new Set();

		const requestShortener = runtimeTemplate.requestShortener;
		// Meta info for each module
		const modulesWithInfo = this._getModulesWithInfo(moduleGraph, runtime);

		// Create mapping from module to info
		const moduleToInfoMap = modulesWithInfoToMap(modulesWithInfo);

		// Set with modules that need a generated namespace object
		/** @type {Set<ConcatenatedModuleInfo>} */
		const neededNamespaceObjects = new Set();

		// Generate source code and analyse scopes
		// Prepare a ReplaceSource for the final source
		for (const info of modulesWithInfo) {
			this._analyseModule(
				modulesWithInfo,
				info,
				dependencyTemplates,
				runtimeTemplate,
				moduleGraph,
				chunkGraph,
				runtime
			);
		}

		// List of all used names to avoid conflicts
		const allUsedNames = new Set(RESERVED_NAMES);

		// List of additional names in scope for module references
		/** @type {Map<string, { usedNames: Set<string>, alreadyCheckedScopes: Set<TODO> }>} */
		const usedNamesInScopeInfo = new Map();
		/**
		 * @param {string} module module identifier
		 * @param {string} id export id
		 * @returns {{ usedNames: Set<string>, alreadyCheckedScopes: Set<TODO> }} info
		 */
		const getUsedNamesInScopeInfo = (module, id) => {
			const key = `${module}-${id}`;
			let info = usedNamesInScopeInfo.get(key);
			if (info === undefined) {
				info = {
					usedNames: new Set(),
					alreadyCheckedScopes: new Set()
				};
				usedNamesInScopeInfo.set(key, info);
			}
			return info;
		};

		// Set of already checked scopes
		const ignoredScopes = new Set();

		// get all global names
		for (const info of modulesWithInfo) {
			if (info.type === "concatenated") {
				const superClassExpressions = [];

				// ignore symbols from moduleScope
				if (info.moduleScope) {
					ignoredScopes.add(info.moduleScope);

					// The super class expression in class scopes behaves weird
					// We store ranges of all super class expressions to make
					// renaming to work correctly
					for (const childScope of info.moduleScope.childScopes) {
						if (childScope.type !== "class") continue;
						const block = childScope.block;
						if (
							(block.type === "ClassDeclaration" ||
								block.type === "ClassExpression") &&
							block.superClass
						) {
							superClassExpressions.push({
								range: block.superClass.range,
								variables: childScope.variables
							});
						}
					}
				}

				// add global symbols
				if (info.globalScope) {
					for (const reference of info.globalScope.through) {
						const name = reference.identifier.name;
						if (ConcatenationScope.isModuleReference(name)) {
							const match = ConcatenationScope.matchModuleReference(name);
							if (!match || match.ids.length < 1) continue;
							const binding = getFinalBinding(
								moduleGraph,
								modulesWithInfo[match.index],
								match.ids,
								moduleToInfoMap,
								runtime,
								requestShortener,
								runtimeTemplate,
								neededNamespaceObjects,
								false,
								info.module.buildMeta.strictHarmonyModule,
								true
							);
							if (!binding.ids) continue;
							const {
								usedNames,
								alreadyCheckedScopes
							} = getUsedNamesInScopeInfo(
								binding.info.module.identifier(),
								"name" in binding ? binding.name : ""
							);
							for (const expr of superClassExpressions) {
								if (
									expr.range[0] <= reference.identifier.range[0] &&
									expr.range[1] >= reference.identifier.range[1]
								) {
									for (const variable of expr.variables) {
										usedNames.add(variable.name);
									}
								}
							}
							addScopeSymbols(
								reference.from,
								usedNames,
								alreadyCheckedScopes,
								ignoredScopes
							);
						} else {
							allUsedNames.add(name);
						}
					}
				}
			}
		}

		// generate names for symbols
		for (const info of modulesWithInfo) {
			const { usedNames: namespaceObjectUsedNames } = getUsedNamesInScopeInfo(
				info.module.identifier(),
				""
			);
			switch (info.type) {
				case "concatenated": {
					for (const variable of info.moduleScope.variables) {
						const name = variable.name;
						const { usedNames, alreadyCheckedScopes } = getUsedNamesInScopeInfo(
							info.module.identifier(),
							name
						);
						if (allUsedNames.has(name) || usedNames.has(name)) {
							const references = getAllReferences(variable);
							for (const ref of references) {
								addScopeSymbols(
									ref.from,
									usedNames,
									alreadyCheckedScopes,
									ignoredScopes
								);
							}
							const newName = this.findNewName(
								name,
								allUsedNames,
								usedNames,
								info.module.readableIdentifier(requestShortener)
							);
							allUsedNames.add(newName);
							info.internalNames.set(name, newName);
							const source = info.source;
							const allIdentifiers = new Set(
								references.map(r => r.identifier).concat(variable.identifiers)
							);
							for (const identifier of allIdentifiers) {
								const r = identifier.range;
								const path = getPathInAst(info.ast, identifier);
								if (
									path &&
									path.length > 1 &&
									path[1].type === "Property" &&
									path[1].shorthand
								) {
									source.insert(r[1], `: ${newName}`);
								} else {
									source.replace(r[0], r[1] - 1, newName);
								}
							}
						} else {
							allUsedNames.add(name);
							info.internalNames.set(name, name);
						}
					}
					let namespaceObjectName;
					if (info.namespaceExportSymbol) {
						namespaceObjectName = info.internalNames.get(
							info.namespaceExportSymbol
						);
					} else {
						namespaceObjectName = this.findNewName(
							"namespaceObject",
							allUsedNames,
							namespaceObjectUsedNames,
							info.module.readableIdentifier(requestShortener)
						);
						allUsedNames.add(namespaceObjectName);
					}
					info.namespaceObjectName = namespaceObjectName;
					break;
				}
				case "external": {
					const externalName = this.findNewName(
						"",
						allUsedNames,
						namespaceObjectUsedNames,
						info.module.readableIdentifier(requestShortener)
					);
					allUsedNames.add(externalName);
					info.name = externalName;
					break;
				}
			}
			if (
				info.module.buildMeta.exportsType === "default" ||
				info.module.buildMeta.exportsType === "flagged" ||
				info.module.buildMeta.exportsType === "dynamic" ||
				!info.module.buildMeta.exportsType
			) {
				const externalNameInterop = this.findNewName(
					"namespaceObject",
					allUsedNames,
					namespaceObjectUsedNames,
					info.module.readableIdentifier(requestShortener)
				);
				allUsedNames.add(externalNameInterop);
				info.interopNamespaceObjectName = externalNameInterop;
			}
			if (
				info.module.buildMeta.exportsType === "dynamic" ||
				!info.module.buildMeta.exportsType
			) {
				const externalNameInterop = this.findNewName(
					"default",
					allUsedNames,
					namespaceObjectUsedNames,
					info.module.readableIdentifier(requestShortener)
				);
				allUsedNames.add(externalNameInterop);
				info.interopDefaultAccessName = externalNameInterop;
			}
		}

		// Find and replace references to modules
		for (const info of modulesWithInfo) {
			if (info.type === "concatenated") {
				for (const reference of info.globalScope.through) {
					const name = reference.identifier.name;
					const match = ConcatenationScope.matchModuleReference(name);
					if (match) {
						const finalName = getFinalName(
							moduleGraph,
							modulesWithInfo[match.index],
							match.ids,
							moduleToInfoMap,
							runtime,
							requestShortener,
							runtimeTemplate,
							neededNamespaceObjects,
							match.call,
							!match.directImport,
							info.module.buildMeta.strictHarmonyModule,
							match.asiSafe
						);
						const r = reference.identifier.range;
						const source = info.source;
						// range is extended by 2 chars to cover the appended "._"
						source.replace(r[0], r[1] + 1, finalName);
					}
				}
			}
		}

		// Map with all root exposed used exports
		/** @type {Map<string, function(RequestShortener): string>} */
		const exportsMap = new Map();

		// Set with all root exposed unused exports
		/** @type {Set<string>} */
		const unusedExports = new Set();

		const rootInfo = /** @type {ConcatenatedModuleInfo} */ (moduleToInfoMap.get(
			this.rootModule
		));
		const strictHarmonyModule = rootInfo.module.buildMeta.strictHarmonyModule;
		const exportsInfo = moduleGraph.getExportsInfo(rootInfo.module);
		for (const exportInfo of exportsInfo.orderedExports) {
			const name = exportInfo.name;
			if (exportInfo.provided === false) continue;
			const used = exportInfo.getUsedName(undefined, runtime);
			if (!used) {
				unusedExports.add(name);
				continue;
			}
			exportsMap.set(used, requestShortener => {
				const finalName = getFinalName(
					moduleGraph,
					rootInfo,
					[name],
					moduleToInfoMap,
					runtime,
					requestShortener,
					runtimeTemplate,
					neededNamespaceObjects,
					false,
					false,
					strictHarmonyModule,
					true
				);
				return `/* ${
					exportInfo.isReexport() ? "reexport" : "binding"
				} */ ${finalName}`;
			});
		}

		const result = new ConcatSource();

		// add harmony compatibility flag (must be first because of possible circular dependencies)
		if (
			moduleGraph.getExportsInfo(this).otherExportsInfo.getUsed(runtime) !==
			UsageState.Unused
		) {
			result.add(`// ESM COMPAT FLAG\n`);
			result.add(
				runtimeTemplate.defineEsModuleFlagStatement({
					exportsArgument: this.exportsArgument,
					runtimeRequirements
				})
			);
		}

		// define exports
		if (exportsMap.size > 0) {
			runtimeRequirements.add(RuntimeGlobals.exports);
			runtimeRequirements.add(RuntimeGlobals.definePropertyGetters);
			const definitions = [];
			for (const [key, value] of exportsMap) {
				definitions.push(
					`\n  ${JSON.stringify(key)}: ${runtimeTemplate.returningFunction(
						value(requestShortener)
					)}`
				);
			}
			result.add(`\n// EXPORTS\n`);
			result.add(
				`${RuntimeGlobals.definePropertyGetters}(${
					this.exportsArgument
				}, {${definitions.join(",")}\n});\n`
			);
		}

		// list unused exports
		if (unusedExports.size > 0) {
			result.add(
				`\n// UNUSED EXPORTS: ${joinIterableWithComma(unusedExports)}\n`
			);
		}

		// generate namespace objects
		const namespaceObjectSources = new Map();
		for (const info of neededNamespaceObjects) {
			if (info.namespaceExportSymbol) continue;
			const nsObj = [];
			const exportsInfo = moduleGraph.getExportsInfo(info.module);
			for (const exportInfo of exportsInfo.orderedExports) {
				if (exportInfo.provided === false) continue;
				const usedName = exportInfo.getUsedName(undefined, runtime);
				if (usedName) {
					const finalName = getFinalName(
						moduleGraph,
						info,
						[exportInfo.name],
						moduleToInfoMap,
						runtime,
						requestShortener,
						runtimeTemplate,
						neededNamespaceObjects,
						false,
						undefined,
						info.module.buildMeta.strictHarmonyModule,
						true
					);
					nsObj.push(
						`\n  ${JSON.stringify(
							usedName
						)}: ${runtimeTemplate.returningFunction(finalName)}`
					);
				}
			}
			const name = info.namespaceObjectName;
			const defineGetters =
				nsObj.length > 0
					? `${RuntimeGlobals.definePropertyGetters}(${name}, {${nsObj.join(
							","
					  )}\n});\n`
					: "";
			if (nsObj.length > 0)
				runtimeRequirements.add(RuntimeGlobals.definePropertyGetters);
			namespaceObjectSources.set(
				info,
				`
// NAMESPACE OBJECT: ${info.module.readableIdentifier(requestShortener)}
var ${name} = {};
${RuntimeGlobals.makeNamespaceObject}(${name});
${defineGetters}`
			);
			runtimeRequirements.add(RuntimeGlobals.makeNamespaceObject);
		}

		// define required namespace objects (must be before evaluation modules)
		for (const info of modulesWithInfo) {
			if (info.type === "concatenated") {
				const source = namespaceObjectSources.get(info);
				if (!source) continue;
				result.add(source);
			}
		}

		// evaluate modules in order
		for (const info of modulesWithInfo) {
			let name;
			switch (info.type) {
				case "concatenated": {
					result.add(
						`\n// CONCATENATED MODULE: ${info.module.readableIdentifier(
							requestShortener
						)}\n`
					);
					result.add(info.source);
					if (info.runtimeRequirements) {
						for (const r of info.runtimeRequirements) {
							runtimeRequirements.add(r);
						}
					}
					name = info.namespaceObjectName;
					break;
				}
				case "external":
					result.add(
						`\n// EXTERNAL MODULE: ${info.module.readableIdentifier(
							requestShortener
						)}\n`
					);
					runtimeRequirements.add(RuntimeGlobals.require);
					result.add(
						`var ${info.name} = __webpack_require__(${JSON.stringify(
							chunkGraph.getModuleId(info.module)
						)});`
					);
					name = info.name;
					break;
				default:
					// @ts-expect-error never is expected here
					throw new Error(`Unsupported concatenation entry type ${info.type}`);
			}
			if (info.interopNamespaceObjectUsed) {
				if (info.module.buildMeta.exportsType === "default") {
					runtimeRequirements.add(RuntimeGlobals.createFakeNamespaceObject);
					result.add(
						`\nvar ${info.interopNamespaceObjectName} = /*#__PURE__*/${RuntimeGlobals.createFakeNamespaceObject}(${name}, 2);\n`
					);
				} else if (
					info.module.buildMeta.exportsType === "flagged" ||
					info.module.buildMeta.exportsType === "dynamic" ||
					!info.module.buildMeta.exportsType
				) {
					runtimeRequirements.add(RuntimeGlobals.createFakeNamespaceObject);
					result.add(
						`\nvar ${info.interopNamespaceObjectName} = /*#__PURE__*/${RuntimeGlobals.createFakeNamespaceObject}(${name});\n`
					);
				}
			}
			if (info.interopDefaultAccessUsed) {
				runtimeRequirements.add(RuntimeGlobals.compatGetDefaultExport);
				result.add(
					`\nvar ${info.interopDefaultAccessName} = /*#__PURE__*/${RuntimeGlobals.compatGetDefaultExport}(${name});\n`
				);
			}
		}

		/** @type {CodeGenerationResult} */
		const resultEntry = {
			sources: new Map([["javascript", new CachedSource(result)]]),
			runtimeRequirements
		};

		return resultEntry;
	}

	/**
	 * @param {ModuleInfo[]} modulesWithInfo modulesWithInfo
	 * @param {ModuleInfo} info info
	 * @param {DependencyTemplates} dependencyTemplates dependencyTemplates
	 * @param {RuntimeTemplate} runtimeTemplate runtimeTemplate
	 * @param {ModuleGraph} moduleGraph moduleGraph
	 * @param {ChunkGraph} chunkGraph chunkGraph
	 * @param {RuntimeSpec} runtime runtime
	 */
	_analyseModule(
		modulesWithInfo,
		info,
		dependencyTemplates,
		runtimeTemplate,
		moduleGraph,
		chunkGraph,
		runtime
	) {
		if (info.type === "concatenated") {
			const m = info.module;
			try {
				// Create a concatenation scope to track and capture information
				const concatenationScope = new ConcatenationScope(
					modulesWithInfo,
					info
				);

				// TODO cache codeGeneration results
				const codeGenResult = m.codeGeneration({
					dependencyTemplates,
					runtimeTemplate,
					moduleGraph,
					chunkGraph,
					runtime,
					concatenationScope
				});
				const source = codeGenResult.sources.get("javascript");
				const code = source.source().toString();
				let ast;
				try {
					ast = JavascriptParser._parse(code, {
						sourceType: "module"
					});
				} catch (err) {
					if (
						err.loc &&
						typeof err.loc === "object" &&
						typeof err.loc.line === "number"
					) {
						const lineNumber = err.loc.line;
						const lines = code.split("\n");
						err.message +=
							"\n| " +
							lines
								.slice(Math.max(0, lineNumber - 3), lineNumber + 2)
								.join("\n| ");
					}
					throw err;
				}
				const scopeManager = eslintScope.analyze(ast, {
					ecmaVersion: 6,
					sourceType: "module",
					optimistic: true,
					ignoreEval: true,
					impliedStrict: true
				});
				const globalScope = scopeManager.acquire(ast);
				const moduleScope = globalScope.childScopes[0];
				const resultSource = new ReplaceSource(source);
				info.runtimeRequirements = codeGenResult.runtimeRequirements;
				info.ast = ast;
				info.internalSource = source;
				info.source = resultSource;
				info.globalScope = globalScope;
				info.moduleScope = moduleScope;
			} catch (err) {
				err.message += `\nwhile analysing module ${m.identifier()} for concatenation`;
				throw err;
			}
		}
	}

	/**
	 * @param {ChunkGraph} chunkGraph the chunk graph
	 * @param {DependencyTemplates} dependencyTemplates dependency templates
	 * @param {RuntimeSpec} runtime the runtime
	 * @returns {string} hash
	 */
	_getHashDigest(chunkGraph, dependencyTemplates, runtime) {
		const hash = chunkGraph.getModuleHash(this, runtime);
		const dtHash = dependencyTemplates.getHash();
		return `${hash}-${dtHash}`;
	}

	/**
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @param {RuntimeSpec} runtime the runtime
	 * @returns {ModuleInfo[]} module info items
	 */
	_getModulesWithInfo(moduleGraph, runtime) {
		const orderedConcatenationList = this._createConcatenationList(
			this.rootModule,
			this._modules,
			undefined,
			moduleGraph
		);
		return orderedConcatenationList.map((info, index) => {
			switch (info.type) {
				case "concatenated": {
					return {
						type: "concatenated",
						module: info.module,
						index,
						ast: undefined,
						internalSource: undefined,
						runtimeRequirements: undefined,
						source: undefined,
						globalScope: undefined,
						moduleScope: undefined,
						internalNames: new Map(),
						exportMap: undefined,
						rawExportMap: undefined,
						namespaceExportSymbol: undefined,
						namespaceObjectName: undefined,
						interopNamespaceObjectUsed: false,
						interopNamespaceObjectName: undefined,
						interopDefaultAccessUsed: false,
						interopDefaultAccessName: undefined
					};
				}
				case "external":
					return {
						type: "external",
						module: info.module,
						index,
						name: undefined,
						interopNamespaceObjectUsed: false,
						interopNamespaceObjectName: undefined,
						interopDefaultAccessUsed: false,
						interopDefaultAccessName: undefined
					};
				default:
					throw new Error(`Unsupported concatenation entry type ${info.type}`);
			}
		});
	}

	findNewName(oldName, usedNamed1, usedNamed2, extraInfo) {
		let name = oldName;

		if (name === ConcatenationScope.DEFAULT_EXPORT) {
			name = "";
		}
		if (name === ConcatenationScope.NAMESPACE_OBJECT_EXPORT) {
			name = "namespaceObject";
		}

		// Remove uncool stuff
		extraInfo = extraInfo.replace(
			/\.+\/|(\/index)?\.([a-zA-Z0-9]{1,4})($|\s|\?)|\s*\+\s*\d+\s*modules/g,
			""
		);

		const splittedInfo = extraInfo.split("/");
		while (splittedInfo.length) {
			name = splittedInfo.pop() + (name ? "_" + name : "");
			const nameIdent = Template.toIdentifier(name);
			if (
				!usedNamed1.has(nameIdent) &&
				(!usedNamed2 || !usedNamed2.has(nameIdent))
			)
				return nameIdent;
		}

		let i = 0;
		let nameWithNumber = Template.toIdentifier(`${name}_${i}`);
		while (
			usedNamed1.has(nameWithNumber) ||
			(usedNamed2 && usedNamed2.has(nameWithNumber))
		) {
			i++;
			nameWithNumber = Template.toIdentifier(`${name}_${i}`);
		}
		return nameWithNumber;
	}

	/**
	 * @param {Hash} hash the hash used to track dependencies
	 * @param {UpdateHashContext} context context
	 * @returns {void}
	 */
	updateHash(hash, context) {
		const { chunkGraph, runtime } = context;
		for (const info of this._createConcatenationList(
			this.rootModule,
			this._modules,
			runtime,
			chunkGraph.moduleGraph
		)) {
			switch (info.type) {
				case "concatenated":
					info.module.updateHash(hash, context);
					break;
				case "external":
					hash.update(`${chunkGraph.getModuleId(info.module)}`);
					break;
			}
		}
		super.updateHash(hash, context);
	}

	static deserialize(context) {
		const obj = new ConcatenatedModule({
			identifier: undefined,
			rootModule: undefined,
			modules: undefined
		});
		obj.deserialize(context);
		return obj;
	}
}

makeSerializable(ConcatenatedModule, "webpack/lib/optimize/ConcatenatedModule");

module.exports = ConcatenatedModule;