1 |
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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 |
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15 |
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16 |
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17 |
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18 |
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19 |
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20 |
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21 |
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22 |
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23 |
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24 |
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25 |
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26 |
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27 |
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28 |
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29 |
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30 |
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31 |
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32 |
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33 | const globToRegexpCache = new WeakMap();
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34 |
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35 |
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36 |
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37 |
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38 |
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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 | |
55 |
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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 | |
61 |
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62 |
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63 |
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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 | |
116 |
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117 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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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