change DependencyReference.importedNames to be always an string[][]

lib/Dependency.js

@@ -83,7 +83,7 @@ class Dependency {
 		if (!module) return null;
 		return new DependencyReference(
 			() => moduleGraph.getModule(this),
-			true,
+			DependencyReference.NS_OBJECT_IMPORTED,
 			this.weak
 		);
 	}

lib/FlagDependencyUsagePlugin.js

@@ -7,6 +7,7 @@
 
 const { UsageState } = require("./ModuleGraph");
 const { STAGE_DEFAULT } = require("./OptimizationStages");
+const { NS_OBJECT_IMPORTED } = require("./dependencies/DependencyReference");
 const Queue = require("./util/Queue");
 
 /** @typedef {import("./Compiler")} Compiler */
@@ -15,9 +16,6 @@ const Queue = require("./util/Queue");
 /** @typedef {import("./Module")} Module */
 /** @typedef {import("./ModuleGraph").ExportsInfo} ExportsInfo */
 
-const NS_OBJ_USED = [[]];
-const NOTHING_USED = [];
-
 class FlagDependencyUsagePlugin {
 	/**
 	 * @param {Compiler} compiler the compiler instance
@@ -92,6 +90,7 @@ class FlagDependencyUsagePlugin {
 						} else {
 							// for a module without side effects we stop tracking usage here when no export is used
 							// This module won't be evaluated in this case
+							// TODO webpack 6 remove this check
 							if (module.factoryMeta.sideEffectFree) return;
 							if (exportsInfo.setUsedForSideEffectsOnly()) {
 								queue.enqueue(module);
@@ -122,14 +121,7 @@ class FlagDependencyUsagePlugin {
 						const referenceModule = reference.module;
 						const importedNames = reference.importedNames;
 
-						processModule(
+						processModule(referenceModule, importedNames);
-							referenceModule,
-							importedNames === false
-								? NOTHING_USED
-								: importedNames === true
-								? NS_OBJ_USED
-								: importedNames.map(n => (Array.isArray(n) ? n : [n]))
-						);
 					};
 
 					for (const module of modules) {
@@ -145,7 +137,7 @@ class FlagDependencyUsagePlugin {
 						for (const dep of deps) {
 							const module = moduleGraph.getModule(dep);
 							if (module) {
-								processModule(module, NS_OBJ_USED);
+								processModule(module, NS_OBJECT_IMPORTED);
 							}
 						}
 					}

lib/dependencies/DependencyReference.js

@@ -7,6 +7,7 @@
 
 /** @typedef {import("../Module")} Module */
 /** @typedef {() => Module} ModuleCallback */
+/** @typedef {string[]} StringArray */
 
 class DependencyReference {
 	// module must be dynamic, you must pass a function returning a module
@@ -14,7 +15,7 @@ class DependencyReference {
 	/**
 	 *
 	 * @param {ModuleCallback} moduleCallback a callback to get the referenced module
-	 * @param {(string | string[])[] | boolean} importedNames imported named from the module
+	 * @param {StringArray[]} importedNames imported named from the module
 	 * @param {boolean=} weak if this is a weak reference
 	 * @param {number} order the order information or NaN if don't care
 	 */
@@ -65,4 +66,7 @@ class DependencyReference {
 	}
 }
 
+DependencyReference.NO_IMPORTED_NAMES = [];
+DependencyReference.NS_OBJECT_IMPORTED = [[]];
+
 module.exports = DependencyReference;

lib/dependencies/HarmonyExportImportedSpecifierDependency.js

@@ -339,12 +339,13 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 			case "reexport-named-default":
 				return new DependencyReference(
 					mode.getModule,
-					["default"],
+					[["default"]],
 					false,
 					this.sourceOrder
 				);
 
 			case "reexport-partial-namespace-object": {
+				/** @type {string[][]} */
 				const importedNames = [];
 				const processExportsInfo = (prefix, exportsInfo) => {
 					for (const exportInfo of exportsInfo.orderedExports) {
@@ -377,7 +378,7 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 			case "reexport-non-harmony-undefined":
 				return new DependencyReference(
 					mode.getModule,
-					true,
+					DependencyReference.NS_OBJECT_IMPORTED,
 					false,
 					this.sourceOrder
 				);
@@ -393,7 +394,7 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 			case "dynamic-reexport":
 				return new DependencyReference(
 					mode.getModule,
-					true,
+					DependencyReference.NS_OBJECT_IMPORTED,
 					false,
 					this.sourceOrder
 				);

lib/dependencies/HarmonyImportDependency.js

@@ -40,7 +40,7 @@ class HarmonyImportDependency extends ModuleDependency {
 		if (!moduleGraph.getModule(this)) return null;
 		return new DependencyReference(
 			() => moduleGraph.getModule(this),
-			false,
+			DependencyReference.NO_IMPORTED_NAMES,
 			this.weak,
 			this.sourceOrder
 		);

lib/dependencies/HarmonyImportSpecifierDependency.js

@@ -81,7 +81,9 @@ class HarmonyImportSpecifierDependency extends HarmonyImportDependency {
 		const ids = this.getIds(moduleGraph);
 		return new DependencyReference(
 			() => moduleGraph.getModule(this),
-			ids.length > 0 && !this.namespaceObjectAsContext ? [ids] : true,
+			ids.length > 0 && !this.namespaceObjectAsContext
+				? [ids]
+				: DependencyReference.NS_OBJECT_IMPORTED,
 			false,
 			this.sourceOrder
 		);

lib/dependencies/RequireIncludeDependency.js

@@ -33,7 +33,7 @@ class RequireIncludeDependency extends ModuleDependency {
 		// This doesn't use any export
 		return new DependencyReference(
 			() => moduleGraph.getModule(this),
-			false,
+			DependencyReference.NO_IMPORTED_NAMES,
 			false
 		);
 	}

lib/dependencies/StaticExportsDependency.js

@@ -41,7 +41,7 @@ class StaticExportsDependency extends NullDependency {
 		// TODO introduce a flag whether exports can be mangled or not
 		return new DependencyReference(
 			() => moduleGraph.getParentModule(this),
-			true,
+			DependencyReference.NS_OBJECT_IMPORTED,
 			false
 		);
 	}

lib/dependencies/WebAssemblyExportImportedDependency.js

@@ -34,7 +34,7 @@ class WebAssemblyExportImportedDependency extends ModuleDependency {
 
 		return new DependencyReference(
 			() => moduleGraph.getModule(this),
-			[this.name],
+			[[this.name]],
 			false
 		);
 	}

lib/dependencies/WebAssemblyImportDependency.js

@@ -43,7 +43,7 @@ class WebAssemblyImportDependency extends ModuleDependency {
 
 		return new DependencyReference(
 			() => moduleGraph.getModule(this),
-			[this.name],
+			[[this.name]],
 			false
 		);
 	}

lib/optimize/ModuleConcatenationPlugin.js

@@ -391,7 +391,8 @@ class ModuleConcatenationPlugin {
 					ref =>
 						ref &&
 						ref.module &&
-						(Array.isArray(ref.importedNames) ||
+						((Array.isArray(ref.importedNames) &&
+							ref.importedNames.every(i => i.length > 0)) ||
 							Array.isArray(moduleGraph.getProvidedExports(ref.module)))
 				)
 

lib/wasm/WasmFinalizeExportsPlugin.js

@@ -47,10 +47,9 @@ class WasmFinalizeExportsPlugin {
 									const importedNames = ref.importedNames;
 
 									if (Array.isArray(importedNames)) {
-										importedNames.forEach(nameOrNames => {
+										importedNames.forEach(names => {
-											const name = Array.isArray(nameOrNames)
+											if (names.length === 0) return;
-												? nameOrNames[0]
+											const name = names[0];
-												: nameOrNames;
 											// 3. and uses a func with an incompatible JS signature
 											if (
 												Object.prototype.hasOwnProperty.call(

test/__snapshots__/StatsTestCases.test.js.snap

@@ -2295,6 +2295,7 @@ Built at: Thu Jan 01 1970 00:00:00 GMT
 Entrypoint index = index.js
 Entrypoint entry = entry.js
  [10] ./index.js 150 bytes {826} [built]
+      ModuleConcatenation bailout: Cannot concat with ./cjs.js (<- Module is not an ECMAScript module)
       ModuleConcatenation bailout: Cannot concat with ./entry.js (<- Module is an entry point)
       ModuleConcatenation bailout: Cannot concat with ./eval.js (<- Module uses eval())
       ModuleConcatenation bailout: Cannot concat with ./module-id.js (<- Module uses module.id)

test/configCases/deep-scope-analysis/remove-export-scope-hoisting/webpack.config.js

@@ -1,5 +1,8 @@
 const DependencyReference = require("../../../../").dependencies
 	.DependencyReference;
+
+/** @typedef {import("../../../../lib/Compilation")} Compilation */
+
 module.exports = {
 	optimization: {
 		usedExports: true,
@@ -7,7 +10,13 @@ module.exports = {
 	},
 	plugins: [
 		function() {
-			this.hooks.compilation.tap("Test", compilation => {
+			this.hooks.compilation.tap(
+				"Test",
+				/**
+				 * @param {Compilation} compilation the compilation
+				 * @returns {void}
+				 */
+				compilation => {
 					compilation.hooks.dependencyReference.tap("Test", (ref, dep) => {
 						const module = compilation.moduleGraph.getParentModule(dep);
 						if (
@@ -24,14 +33,15 @@ module.exports = {
 							);
 							return new DependencyReference(
 								() => ref.module,
-							newExports.length > 0 ? newExports : false,
+								newExports,
 								ref.weak,
 								ref.order
 							);
 						}
 						return ref;
 					});
-			});
+				}
+			);
 		}
 	]
 };

test/configCases/deep-scope-analysis/remove-export/webpack.config.js

@@ -1,5 +1,8 @@
 const DependencyReference = require("../../../../").dependencies
 	.DependencyReference;
+
+/** @typedef {import("../../../../lib/Compilation")} Compilation */
+
 module.exports = {
 	optimization: {
 		usedExports: true,
@@ -24,7 +27,7 @@ module.exports = {
 						);
 						return new DependencyReference(
 							() => ref.module,
-							newExports.length > 0 ? newExports : false,
+							newExports,
 							ref.weak,
 							ref.order
 						);

test/configCases/parsing/harmony-this-concat/webpack.config.js

@@ -1,4 +1,3 @@
-var webpack = require("../../../../");
 module.exports = {
 	module: {
 		strictThisContextOnImports: true