| 1 | /*
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| 2 | MIT License http://www.opensource.org/licenses/mit-license.php
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| 3 | Author Tobias Koppers @sokra
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| 4 | */
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| 5 |
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| 6 | "use strict";
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| 7 |
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| 8 | const glob2regexp = require("glob-to-regexp");
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| 9 | const { STAGE_DEFAULT } = require("../OptimizationStages");
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| 10 | const HarmonyExportImportedSpecifierDependency = require("../dependencies/HarmonyExportImportedSpecifierDependency");
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| 11 | const HarmonyImportSpecifierDependency = require("../dependencies/HarmonyImportSpecifierDependency");
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| 12 | const formatLocation = require("../formatLocation");
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| 13 |
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| 14 | /** @typedef {import("../Compiler")} Compiler */
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| 15 | /** @typedef {import("../Dependency")} Dependency */
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| 16 | /** @typedef {import("../Module")} Module */
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| 17 | /** @typedef {import("../javascript/JavascriptParser")} JavascriptParser */
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| 18 |
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| 19 | /**
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| 20 | * @typedef {Object} ExportInModule
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| 21 | * @property {Module} module the module
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| 22 | * @property {string} exportName the name of the export
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| 23 | * @property {boolean} checked if the export is conditional
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| 24 | */
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| 25 |
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| 26 | /**
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| 27 | * @typedef {Object} ReexportInfo
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| 28 | * @property {Map<string, ExportInModule[]>} static
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| 29 | * @property {Map<Module, Set<string>>} dynamic
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| 30 | */
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| 31 |
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| 32 | /** @type {WeakMap<any, Map<string, RegExp>>} */
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| 33 | const globToRegexpCache = new WeakMap();
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| 34 |
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| 35 | /**
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| 36 | * @param {string} glob the pattern
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| 37 | * @param {Map<string, RegExp>} cache the glob to RegExp cache
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| 38 | * @returns {RegExp} a regular expression
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| 39 | */
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| 40 | const globToRegexp = (glob, cache) => {
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| 41 | const cacheEntry = cache.get(glob);
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| 42 | if (cacheEntry !== undefined) return cacheEntry;
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| 43 | if (!glob.includes("/")) {
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| 44 | glob = `**/${glob}`;
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| 45 | }
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| 46 | const baseRegexp = glob2regexp(glob, { globstar: true, extended: true });
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| 47 | const regexpSource = baseRegexp.source;
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| 48 | const regexp = new RegExp("^(\\./)?" + regexpSource.slice(1));
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| 49 | cache.set(glob, regexp);
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| 50 | return regexp;
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| 51 | };
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| 52 |
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| 53 | class SideEffectsFlagPlugin {
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| 54 | /**
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| 55 | * @param {boolean} analyseSource analyse source code for side effects
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| 56 | */
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| 57 | constructor(analyseSource = true) {
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| 58 | this._analyseSource = analyseSource;
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| 59 | }
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| 60 | /**
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| 61 | * Apply the plugin
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| 62 | * @param {Compiler} compiler the compiler instance
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| 63 | * @returns {void}
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| 64 | */
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| 65 | apply(compiler) {
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| 66 | let cache = globToRegexpCache.get(compiler.root);
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| 67 | if (cache === undefined) {
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| 68 | cache = new Map();
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| 69 | globToRegexpCache.set(compiler.root, cache);
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| 70 | }
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| 71 | compiler.hooks.compilation.tap(
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| 72 | "SideEffectsFlagPlugin",
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| 73 | (compilation, { normalModuleFactory }) => {
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| 74 | const moduleGraph = compilation.moduleGraph;
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| 75 | normalModuleFactory.hooks.module.tap(
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| 76 | "SideEffectsFlagPlugin",
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| 77 | (module, data) => {
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| 78 | const resolveData = data.resourceResolveData;
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| 79 | if (
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| 80 | resolveData &&
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| 81 | resolveData.descriptionFileData &&
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| 82 | resolveData.relativePath
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| 83 | ) {
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| 84 | const sideEffects = resolveData.descriptionFileData.sideEffects;
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| 85 | if (sideEffects !== undefined) {
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| 86 | if (module.factoryMeta === undefined) {
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| 87 | module.factoryMeta = {};
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| 88 | }
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| 89 | const hasSideEffects =
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| 90 | SideEffectsFlagPlugin.moduleHasSideEffects(
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| 91 | resolveData.relativePath,
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| 92 | sideEffects,
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| 93 | cache
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| 94 | );
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| 95 | module.factoryMeta.sideEffectFree = !hasSideEffects;
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| 96 | }
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| 97 | }
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| 98 |
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| 99 | return module;
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| 100 | }
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| 101 | );
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| 102 | normalModuleFactory.hooks.module.tap(
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| 103 | "SideEffectsFlagPlugin",
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| 104 | (module, data) => {
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| 105 | if (typeof data.settings.sideEffects === "boolean") {
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| 106 | if (module.factoryMeta === undefined) {
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| 107 | module.factoryMeta = {};
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| 108 | }
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| 109 | module.factoryMeta.sideEffectFree = !data.settings.sideEffects;
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| 110 | }
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| 111 | return module;
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| 112 | }
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| 113 | );
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| 114 | if (this._analyseSource) {
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| 115 | /**
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| 116 | * @param {JavascriptParser} parser the parser
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| 117 | * @returns {void}
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| 118 | */
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| 119 | const parserHandler = parser => {
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| 120 | let sideEffectsStatement;
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| 121 | parser.hooks.program.tap("SideEffectsFlagPlugin", () => {
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| 122 | sideEffectsStatement = undefined;
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| 123 | });
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| 124 | parser.hooks.statement.tap(
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| 125 | { name: "SideEffectsFlagPlugin", stage: -100 },
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| 126 | statement => {
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| 127 | if (sideEffectsStatement) return;
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| 128 | if (parser.scope.topLevelScope !== true) return;
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| 129 | switch (statement.type) {
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| 130 | case "ExpressionStatement":
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| 131 | if (
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| 132 | !parser.isPure(statement.expression, statement.range[0])
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| 133 | ) {
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| 134 | sideEffectsStatement = statement;
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| 135 | }
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| 136 | break;
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| 137 | case "IfStatement":
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| 138 | case "WhileStatement":
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| 139 | case "DoWhileStatement":
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| 140 | if (!parser.isPure(statement.test, statement.range[0])) {
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| 141 | sideEffectsStatement = statement;
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| 142 | }
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| 143 | // statement hook will be called for child statements too
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| 144 | break;
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| 145 | case "ForStatement":
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| 146 | if (
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| 147 | !parser.isPure(statement.init, statement.range[0]) ||
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| 148 | !parser.isPure(
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| 149 | statement.test,
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| 150 | statement.init
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| 151 | ? statement.init.range[1]
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| 152 | : statement.range[0]
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| 153 | ) ||
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| 154 | !parser.isPure(
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| 155 | statement.update,
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| 156 | statement.test
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| 157 | ? statement.test.range[1]
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| 158 | : statement.init
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| 159 | ? statement.init.range[1]
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| 160 | : statement.range[0]
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| 161 | )
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| 162 | ) {
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| 163 | sideEffectsStatement = statement;
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| 164 | }
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| 165 | // statement hook will be called for child statements too
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| 166 | break;
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| 167 | case "SwitchStatement":
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| 168 | if (
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| 169 | !parser.isPure(statement.discriminant, statement.range[0])
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| 170 | ) {
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| 171 | sideEffectsStatement = statement;
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| 172 | }
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| 173 | // statement hook will be called for child statements too
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| 174 | break;
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| 175 | case "VariableDeclaration":
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| 176 | case "ClassDeclaration":
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| 177 | case "FunctionDeclaration":
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| 178 | if (!parser.isPure(statement, statement.range[0])) {
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| 179 | sideEffectsStatement = statement;
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| 180 | }
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| 181 | break;
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| 182 | case "ExportNamedDeclaration":
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| 183 | case "ExportDefaultDeclaration":
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| 184 | if (
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| 185 | !parser.isPure(statement.declaration, statement.range[0])
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| 186 | ) {
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| 187 | sideEffectsStatement = statement;
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| 188 | }
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| 189 | break;
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| 190 | case "LabeledStatement":
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| 191 | case "BlockStatement":
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| 192 | // statement hook will be called for child statements too
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| 193 | break;
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| 194 | case "EmptyStatement":
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| 195 | break;
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| 196 | case "ExportAllDeclaration":
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| 197 | case "ImportDeclaration":
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| 198 | // imports will be handled by the dependencies
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| 199 | break;
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| 200 | default:
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| 201 | sideEffectsStatement = statement;
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| 202 | break;
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| 203 | }
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| 204 | }
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| 205 | );
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| 206 | parser.hooks.finish.tap("SideEffectsFlagPlugin", () => {
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| 207 | if (sideEffectsStatement === undefined) {
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| 208 | parser.state.module.buildMeta.sideEffectFree = true;
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| 209 | } else {
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| 210 | const { loc, type } = sideEffectsStatement;
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| 211 | moduleGraph
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| 212 | .getOptimizationBailout(parser.state.module)
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| 213 | .push(
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| 214 | () =>
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| 215 | `Statement (${type}) with side effects in source code at ${formatLocation(
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| 216 | loc
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| 217 | )}`
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| 218 | );
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| 219 | }
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| 220 | });
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| 221 | };
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| 222 | for (const key of [
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| 223 | "javascript/auto",
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| 224 | "javascript/esm",
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| 225 | "javascript/dynamic"
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| 226 | ]) {
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| 227 | normalModuleFactory.hooks.parser
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| 228 | .for(key)
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| 229 | .tap("SideEffectsFlagPlugin", parserHandler);
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| 230 | }
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| 231 | }
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| 232 | compilation.hooks.optimizeDependencies.tap(
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| 233 | {
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| 234 | name: "SideEffectsFlagPlugin",
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| 235 | stage: STAGE_DEFAULT
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| 236 | },
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| 237 | modules => {
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| 238 | const logger = compilation.getLogger(
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| 239 | "webpack.SideEffectsFlagPlugin"
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| 240 | );
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| 241 |
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| 242 | logger.time("update dependencies");
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| 243 | for (const module of modules) {
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| 244 | if (module.getSideEffectsConnectionState(moduleGraph) === false) {
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| 245 | const exportsInfo = moduleGraph.getExportsInfo(module);
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| 246 | for (const connection of moduleGraph.getIncomingConnections(
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| 247 | module
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| 248 | )) {
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| 249 | const dep = connection.dependency;
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| 250 | let isReexport;
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| 251 | if (
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| 252 | (isReexport =
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| 253 | dep instanceof
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| 254 | HarmonyExportImportedSpecifierDependency) ||
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| 255 | (dep instanceof HarmonyImportSpecifierDependency &&
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| 256 | !dep.namespaceObjectAsContext)
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| 257 | ) {
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| 258 | // TODO improve for export *
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| 259 | if (isReexport && dep.name) {
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| 260 | const exportInfo = moduleGraph.getExportInfo(
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| 261 | connection.originModule,
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| 262 | dep.name
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| 263 | );
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| 264 | exportInfo.moveTarget(
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| 265 | moduleGraph,
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| 266 | ({ module }) =>
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| 267 | module.getSideEffectsConnectionState(moduleGraph) ===
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| 268 | false,
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| 269 | ({ module: newModule, export: exportName }) => {
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| 270 | moduleGraph.updateModule(dep, newModule);
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| 271 | moduleGraph.addExplanation(
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| 272 | dep,
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| 273 | "(skipped side-effect-free modules)"
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| 274 | );
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| 275 | const ids = dep.getIds(moduleGraph);
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| 276 | dep.setIds(
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| 277 | moduleGraph,
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| 278 | exportName
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| 279 | ? [...exportName, ...ids.slice(1)]
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| 280 | : ids.slice(1)
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| 281 | );
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| 282 | return moduleGraph.getConnection(dep);
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| 283 | }
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| 284 | );
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| 285 | continue;
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| 286 | }
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| 287 | // TODO improve for nested imports
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| 288 | const ids = dep.getIds(moduleGraph);
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| 289 | if (ids.length > 0) {
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| 290 | const exportInfo = exportsInfo.getExportInfo(ids[0]);
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| 291 | const target = exportInfo.getTarget(
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| 292 | moduleGraph,
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| 293 | ({ module }) =>
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| 294 | module.getSideEffectsConnectionState(moduleGraph) ===
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| 295 | false
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| 296 | );
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| 297 | if (!target) continue;
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| 298 |
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| 299 | moduleGraph.updateModule(dep, target.module);
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| 300 | moduleGraph.addExplanation(
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| 301 | dep,
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| 302 | "(skipped side-effect-free modules)"
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| 303 | );
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| 304 | dep.setIds(
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| 305 | moduleGraph,
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| 306 | target.export
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| 307 | ? [...target.export, ...ids.slice(1)]
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| 308 | : ids.slice(1)
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| 309 | );
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| 310 | }
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| 311 | }
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| 312 | }
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| 313 | }
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| 314 | }
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| 315 | logger.timeEnd("update dependencies");
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| 316 | }
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| 317 | );
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| 318 | }
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| 319 | );
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| 320 | }
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| 321 |
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| 322 | static moduleHasSideEffects(moduleName, flagValue, cache) {
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| 323 | switch (typeof flagValue) {
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| 324 | case "undefined":
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| 325 | return true;
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| 326 | case "boolean":
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| 327 | return flagValue;
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| 328 | case "string":
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| 329 | return globToRegexp(flagValue, cache).test(moduleName);
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| 330 | case "object":
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| 331 | return flagValue.some(glob =>
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| 332 | SideEffectsFlagPlugin.moduleHasSideEffects(moduleName, glob, cache)
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| 333 | );
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| 334 | }
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| 335 | }
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| 336 | }
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| 337 | module.exports = SideEffectsFlagPlugin;
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