337 lines
10 KiB
JavaScript
337 lines
10 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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const glob2regexp = require("glob-to-regexp");
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const { STAGE_DEFAULT } = require("../OptimizationStages");
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const HarmonyExportImportedSpecifierDependency = require("../dependencies/HarmonyExportImportedSpecifierDependency");
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const HarmonyImportSpecifierDependency = require("../dependencies/HarmonyImportSpecifierDependency");
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const formatLocation = require("../formatLocation");
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/** @typedef {import("../Compiler")} Compiler */
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/** @typedef {import("../Dependency")} Dependency */
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/** @typedef {import("../Module")} Module */
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/** @typedef {import("../javascript/JavascriptParser")} JavascriptParser */
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/**
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* @typedef {Object} ExportInModule
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* @property {Module} module the module
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* @property {string} exportName the name of the export
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* @property {boolean} checked if the export is conditional
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*/
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/**
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* @typedef {Object} ReexportInfo
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* @property {Map<string, ExportInModule[]>} static
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* @property {Map<Module, Set<string>>} dynamic
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*/
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/** @type {WeakMap<any, Map<string, RegExp>>} */
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const globToRegexpCache = new WeakMap();
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/**
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* @param {string} glob the pattern
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* @param {Map<string, RegExp>} cache the glob to RegExp cache
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* @returns {RegExp} a regular expression
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*/
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const globToRegexp = (glob, cache) => {
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const cacheEntry = cache.get(glob);
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if (cacheEntry !== undefined) return cacheEntry;
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if (!glob.includes("/")) {
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glob = `**/${glob}`;
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}
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const baseRegexp = glob2regexp(glob, { globstar: true, extended: true });
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const regexpSource = baseRegexp.source;
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const regexp = new RegExp("^(\\./)?" + regexpSource.slice(1));
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cache.set(glob, regexp);
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return regexp;
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};
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class SideEffectsFlagPlugin {
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/**
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* @param {boolean} analyseSource analyse source code for side effects
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*/
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constructor(analyseSource = true) {
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this._analyseSource = analyseSource;
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}
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/**
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* Apply the plugin
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* @param {Compiler} compiler the compiler instance
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* @returns {void}
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*/
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apply(compiler) {
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let cache = globToRegexpCache.get(compiler.root);
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if (cache === undefined) {
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cache = new Map();
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globToRegexpCache.set(compiler.root, cache);
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}
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compiler.hooks.compilation.tap(
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"SideEffectsFlagPlugin",
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(compilation, { normalModuleFactory }) => {
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const moduleGraph = compilation.moduleGraph;
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normalModuleFactory.hooks.module.tap(
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"SideEffectsFlagPlugin",
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(module, data) => {
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const resolveData = data.resourceResolveData;
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if (
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resolveData &&
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resolveData.descriptionFileData &&
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resolveData.relativePath
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) {
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const sideEffects = resolveData.descriptionFileData.sideEffects;
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if (sideEffects !== undefined) {
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if (module.factoryMeta === undefined) {
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module.factoryMeta = {};
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}
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const hasSideEffects = SideEffectsFlagPlugin.moduleHasSideEffects(
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resolveData.relativePath,
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sideEffects,
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cache
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);
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module.factoryMeta.sideEffectFree = !hasSideEffects;
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}
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}
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return module;
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}
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);
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normalModuleFactory.hooks.module.tap(
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"SideEffectsFlagPlugin",
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(module, data) => {
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if (typeof data.settings.sideEffects === "boolean") {
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if (module.factoryMeta === undefined) {
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module.factoryMeta = {};
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}
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module.factoryMeta.sideEffectFree = !data.settings.sideEffects;
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}
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return module;
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}
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);
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if (this._analyseSource) {
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/**
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* @param {JavascriptParser} parser the parser
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* @returns {void}
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*/
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const parserHandler = parser => {
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let sideEffectsStatement;
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parser.hooks.program.tap("SideEffectsFlagPlugin", () => {
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sideEffectsStatement = undefined;
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});
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parser.hooks.statement.tap(
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{ name: "SideEffectsFlagPlugin", stage: -100 },
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statement => {
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if (sideEffectsStatement) return;
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if (parser.scope.topLevelScope !== true) return;
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switch (statement.type) {
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case "ExpressionStatement":
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if (
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!parser.isPure(statement.expression, statement.range[0])
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) {
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sideEffectsStatement = statement;
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}
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break;
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case "IfStatement":
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case "WhileStatement":
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case "DoWhileStatement":
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if (!parser.isPure(statement.test, statement.range[0])) {
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sideEffectsStatement = statement;
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}
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// statement hook will be called for child statements too
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break;
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case "ForStatement":
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if (
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!parser.isPure(statement.init, statement.range[0]) ||
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!parser.isPure(
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statement.test,
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statement.init
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? statement.init.range[1]
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: statement.range[0]
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) ||
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!parser.isPure(
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statement.update,
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statement.test
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? statement.test.range[1]
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: statement.init
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? statement.init.range[1]
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: statement.range[0]
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)
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) {
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sideEffectsStatement = statement;
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}
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// statement hook will be called for child statements too
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break;
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case "SwitchStatement":
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if (
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!parser.isPure(statement.discriminant, statement.range[0])
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) {
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sideEffectsStatement = statement;
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}
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// statement hook will be called for child statements too
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break;
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case "VariableDeclaration":
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case "ClassDeclaration":
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case "FunctionDeclaration":
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if (!parser.isPure(statement, statement.range[0])) {
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sideEffectsStatement = statement;
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}
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break;
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case "ExportNamedDeclaration":
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case "ExportDefaultDeclaration":
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if (
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!parser.isPure(statement.declaration, statement.range[0])
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) {
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sideEffectsStatement = statement;
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}
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break;
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case "LabeledStatement":
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case "BlockStatement":
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// statement hook will be called for child statements too
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break;
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case "EmptyStatement":
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break;
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case "ExportAllDeclaration":
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case "ImportDeclaration":
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// imports will be handled by the dependencies
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break;
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default:
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sideEffectsStatement = statement;
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break;
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}
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}
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);
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parser.hooks.finish.tap("SideEffectsFlagPlugin", () => {
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if (sideEffectsStatement === undefined) {
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parser.state.module.buildMeta.sideEffectFree = true;
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} else {
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const { loc, type } = sideEffectsStatement;
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moduleGraph
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.getOptimizationBailout(parser.state.module)
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.push(
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() =>
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`Statement (${type}) with side effects in source code at ${formatLocation(
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loc
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)}`
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);
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}
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});
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};
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for (const key of [
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"javascript/auto",
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"javascript/esm",
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"javascript/dynamic"
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]) {
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normalModuleFactory.hooks.parser
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.for(key)
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.tap("SideEffectsFlagPlugin", parserHandler);
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}
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}
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compilation.hooks.optimizeDependencies.tap(
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{
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name: "SideEffectsFlagPlugin",
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stage: STAGE_DEFAULT
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},
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modules => {
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const logger = compilation.getLogger(
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"webpack.SideEffectsFlagPlugin"
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);
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logger.time("update dependencies");
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for (const module of modules) {
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if (module.getSideEffectsConnectionState(moduleGraph) === false) {
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const exportsInfo = moduleGraph.getExportsInfo(module);
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for (const connection of moduleGraph.getIncomingConnections(
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module
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)) {
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const dep = connection.dependency;
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let isReexport;
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if (
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(isReexport =
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dep instanceof
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HarmonyExportImportedSpecifierDependency) ||
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(dep instanceof HarmonyImportSpecifierDependency &&
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!dep.namespaceObjectAsContext)
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) {
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// TODO improve for export *
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if (isReexport && dep.name) {
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const exportInfo = moduleGraph.getExportInfo(
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connection.originModule,
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dep.name
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);
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exportInfo.moveTarget(
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moduleGraph,
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({ module }) =>
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module.getSideEffectsConnectionState(moduleGraph) ===
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false,
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({ module: newModule, export: exportName }) => {
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moduleGraph.updateModule(dep, newModule);
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moduleGraph.addExplanation(
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dep,
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"(skipped side-effect-free modules)"
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);
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const ids = dep.getIds(moduleGraph);
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dep.setIds(
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moduleGraph,
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exportName
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? [...exportName, ...ids.slice(1)]
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: ids.slice(1)
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);
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return moduleGraph.getConnection(dep);
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}
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);
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continue;
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}
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// TODO improve for nested imports
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const ids = dep.getIds(moduleGraph);
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if (ids.length > 0) {
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const exportInfo = exportsInfo.getExportInfo(ids[0]);
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const target = exportInfo.getTarget(
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moduleGraph,
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({ module }) =>
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module.getSideEffectsConnectionState(moduleGraph) ===
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false
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);
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if (!target) continue;
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moduleGraph.updateModule(dep, target.module);
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moduleGraph.addExplanation(
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dep,
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"(skipped side-effect-free modules)"
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);
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dep.setIds(
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moduleGraph,
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target.export
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? [...target.export, ...ids.slice(1)]
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: ids.slice(1)
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);
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}
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}
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}
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}
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}
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logger.timeEnd("update dependencies");
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}
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);
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}
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);
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}
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static moduleHasSideEffects(moduleName, flagValue, cache) {
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switch (typeof flagValue) {
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case "undefined":
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return true;
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case "boolean":
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return flagValue;
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case "string":
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return globToRegexp(flagValue, cache).test(moduleName);
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case "object":
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return flagValue.some(glob =>
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SideEffectsFlagPlugin.moduleHasSideEffects(moduleName, glob, cache)
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);
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}
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}
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}
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module.exports = SideEffectsFlagPlugin;
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