[pull] main from webpack:main

lib/ChunkGroup.js

@@ -115,16 +115,23 @@ class ChunkGroup {
 	 */
 	addOptions(options) {
 		for (const _key of Object.keys(options)) {
-			const key = /** @type {keyof ChunkGroupOptions} */ (_key);
+			const key =
+				/** @type {keyof ChunkGroupOptions} */
+				(_key);
 			if (this.options[key] === undefined) {
-				/** @type {TODO} */
+				/** @type {EXPECTED_ANY} */
 				(this.options)[key] = options[key];
 			} else if (this.options[key] !== options[key]) {
 				if (key.endsWith("Order")) {
-					/** @type {TODO} */
-					(this.options)[key] = Math.max(
-						/** @type {number} */ (this.options[key]),
-						/** @type {number} */ (options[key])
+					const orderKey =
+						/** @type {Exclude<keyof ChunkGroupOptions, "name" | "fetchPriority">} */
+						(key);
+
+					this.options[orderKey] = Math.max(
+						/** @type {number} */
+						(this.options[orderKey]),
+						/** @type {number} */
+						(options[orderKey])
 					);
 				} else {
 					throw new Error(

lib/Compilation.js

@@ -2354,6 +2354,7 @@ BREAKING CHANGE: Asset processing hooks in Compilation has been merged into a si
 	 */
 	_addEntryItem(context, entry, target, options, callback) {
 		const { name } = options;
+		/** @type {EntryData | undefined} */
 		let entryData =
 			name !== undefined ? this.entries.get(name) : this.globalEntry;
 		if (entryData === undefined) {

lib/ConstPlugin.js

@@ -179,53 +179,21 @@ class ConstPlugin {
 								? statement.alternate
 								: statement.consequent;
 							if (branchToRemove) {
-								// Before removing the dead branch, the hoisted declarations
-								// must be collected.
-								//
-								// Given the following code:
-								//
-								//     if (true) f() else g()
-								//     if (false) {
-								//       function f() {}
-								//       const g = function g() {}
-								//       if (someTest) {
-								//         let a = 1
-								//         var x, {y, z} = obj
-								//       }
-								//     } else {
-								//       …
-								//     }
-								//
-								// the generated code is:
-								//
-								//     if (true) f() else {}
-								//     if (false) {
-								//       var f, x, y, z;   (in loose mode)
-								//       var x, y, z;      (in strict mode)
-								//     } else {
-								//       …
-								//     }
-								//
-								// NOTE: When code runs in strict mode, `var` declarations
-								// are hoisted but `function` declarations don't.
-								//
-								const declarations = parser.scope.isStrict
-									? getHoistedDeclarations(branchToRemove, false)
-									: getHoistedDeclarations(branchToRemove, true);
-								const replacement =
-									declarations.length > 0
-										? `{ var ${declarations.join(", ")}; }`
-										: "{}";
-								const dep = new ConstDependency(
-									replacement,
-									/** @type {Range} */ (branchToRemove.range)
-								);
-								dep.loc = /** @type {SourceLocation} */ (branchToRemove.loc);
-								parser.state.module.addPresentationalDependency(dep);
+								this.eliminateUnusedStatement(parser, branchToRemove);
 							}
 							return bool;
 						}
 					});
+					parser.hooks.unusedStatement.tap(PLUGIN_NAME, statement => {
+						if (
+							parser.scope.isAsmJs ||
+							// Check top level scope here again
+							parser.scope.topLevelScope === true
+						)
+							return;
+						this.eliminateUnusedStatement(parser, statement);
+						return true;
+					});
 					parser.hooks.expressionConditionalOperator.tap(
 						PLUGIN_NAME,
 						expression => {
@@ -534,6 +502,56 @@ class ConstPlugin {
 			}
 		);
 	}
+
+	/**
+	 * Eliminate an unused statement.
+	 * @param {JavascriptParser} parser the parser
+	 * @param {Statement} statement the statement to remove
+	 * @returns {void}
+	 */
+	eliminateUnusedStatement(parser, statement) {
+		// Before removing the unused branch, the hoisted declarations
+		// must be collected.
+		//
+		// Given the following code:
+		//
+		//     if (true) f() else g()
+		//     if (false) {
+		//       function f() {}
+		//       const g = function g() {}
+		//       if (someTest) {
+		//         let a = 1
+		//         var x, {y, z} = obj
+		//       }
+		//     } else {
+		//       …
+		//     }
+		//
+		// the generated code is:
+		//
+		//     if (true) f() else {}
+		//     if (false) {
+		//       var f, x, y, z;   (in loose mode)
+		//       var x, y, z;      (in strict mode)
+		//     } else {
+		//       …
+		//     }
+		//
+		// NOTE: When code runs in strict mode, `var` declarations
+		// are hoisted but `function` declarations don't.
+		//
+		const declarations = parser.scope.isStrict
+			? getHoistedDeclarations(statement, false)
+			: getHoistedDeclarations(statement, true);
+		const replacement =
+			declarations.length > 0 ? `{ var ${declarations.join(", ")}; }` : "{}";
+		const dep = new ConstDependency(
+			`// removed by dead control flow\n${replacement}`,
+			/** @type {Range} */ (statement.range)
+		);
+		dep.loc = /** @type {SourceLocation} */ (statement.loc);
+		parser.state.module.addPresentationalDependency(dep);
+	}
 }
 
 module.exports = ConstPlugin;

lib/asset/AssetGenerator.js

@@ -657,6 +657,7 @@ class AssetGenerator extends Generator {
 	 * @returns {SourceTypes} available types (do not mutate)
 	 */
 	getTypes(module) {
+		/** @type {Set<string>} */
 		const sourceTypes = new Set();
 		const connections = this._moduleGraph.getIncomingConnections(module);
 
@@ -669,27 +670,25 @@ class AssetGenerator extends Generator {
 		}
 
 		if ((module.buildInfo && module.buildInfo.dataUrl) || this.emit === false) {
-			if (sourceTypes) {
+			if (sourceTypes.size > 0) {
 				if (sourceTypes.has("javascript") && sourceTypes.has("css")) {
 					return JS_AND_CSS_URL_TYPES;
-				} else if (sourceTypes.has("javascript")) {
-					return JS_TYPES;
 				} else if (sourceTypes.has("css")) {
 					return CSS_URL_TYPES;
 				}
+				return JS_TYPES;
 			}
 
 			return NO_TYPES;
 		}
 
-		if (sourceTypes) {
+		if (sourceTypes.size > 0) {
 			if (sourceTypes.has("javascript") && sourceTypes.has("css")) {
 				return ASSET_AND_JS_AND_CSS_URL_TYPES;
-			} else if (sourceTypes.has("javascript")) {
-				return ASSET_AND_JS_TYPES;
 			} else if (sourceTypes.has("css")) {
 				return ASSET_AND_CSS_URL_TYPES;
 			}
+			return ASSET_AND_JS_TYPES;
 		}
 
 		return ASSET_TYPES;

lib/asset/AssetSourceGenerator.js

@@ -122,6 +122,7 @@ class AssetSourceGenerator extends Generator {
 	 * @returns {SourceTypes} available types (do not mutate)
 	 */
 	getTypes(module) {
+		/** @type {Set<string>} */
 		const sourceTypes = new Set();
 		const connections = this._moduleGraph.getIncomingConnections(module);
 
@@ -133,12 +134,13 @@ class AssetSourceGenerator extends Generator {
 			sourceTypes.add(connection.originModule.type.split("/")[0]);
 		}
 
-		if (sourceTypes.has("javascript") && sourceTypes.has("css")) {
-			return JS_AND_CSS_URL_TYPES;
-		} else if (sourceTypes.has("javascript")) {
+		if (sourceTypes.size > 0) {
+			if (sourceTypes.has("javascript") && sourceTypes.has("css")) {
+				return JS_AND_CSS_URL_TYPES;
+			} else if (sourceTypes.has("css")) {
+				return CSS_URL_TYPES;
+			}
 			return JS_TYPES;
-		} else if (sourceTypes.has("css")) {
-			return CSS_URL_TYPES;
 		}
 
 		return NO_TYPES;

lib/dependencies/RequireEnsureDependenciesBlockParserPlugin.js

@@ -109,7 +109,10 @@ module.exports = class RequireEnsureDependenciesBlockParserPlugin {
 						}
 						if (successExpression) {
 							if (successExpression.fn.body.type === "BlockStatement") {
+								// Opt-out of Dead Control Flow detection for this block
+								const oldTerminated = parser.scope.terminated;
 								parser.walkStatement(successExpression.fn.body);
+								parser.scope.terminated = oldTerminated;
 							} else {
 								parser.walkExpression(successExpression.fn.body);
 							}

lib/javascript/JavascriptParser.js

@@ -578,7 +578,9 @@ class JavascriptParser extends Parser {
 			/** @type {SyncBailHook<[ThrowStatement | ReturnStatement], boolean | void>} */
 			terminate: new SyncBailHook(["statement"]),
 			/** @type {SyncBailHook<[Program, Comment[]], boolean | void>} */
-			finish: new SyncBailHook(["ast", "comments"])
+			finish: new SyncBailHook(["ast", "comments"]),
+			/** @type {SyncBailHook<[Statement], boolean | void>} */
+			unusedStatement: new SyncBailHook(["statement"])
 		});
 		this.sourceType = sourceType;
 		/** @type {ScopeInfo} */
@@ -1939,8 +1941,13 @@ class JavascriptParser extends Parser {
 		for (let index = 0, len = statements.length; index < len; index++) {
 			const statement = statements[index];
 
-			if (onlyFunctionDeclaration && statement.type !== "FunctionDeclaration")
+			if (
+				onlyFunctionDeclaration &&
+				statement.type !== "FunctionDeclaration" &&
+				this.hooks.unusedStatement.call(/** @type {Statement} */ (statement))
+			) {
 				continue;
+			}
 
 			this.walkStatement(statement);
 

lib/stats/DefaultStatsPrinterPlugin.js

@@ -1454,7 +1454,12 @@ const AVAILABLE_COLORS = {
 	magenta: "\u001B[1m\u001B[35m"
 };
 
-/** @typedef {Required<{ [Key in keyof KnownStatsPrinterFormatters]: (value: Parameters<NonNullable<KnownStatsPrinterFormatters[Key]>>[0], options: Required<KnownStatsPrinterColorFunctions> & StatsPrinterContext, ...args: TODO[]) => string }>} AvailableFormats */
+/**
+ * @template T
+ * @typedef {T extends [infer Head, ...infer Tail] ? Tail : undefined} Tail
+ */
+
+/** @typedef {Required<{ [Key in keyof KnownStatsPrinterFormatters]: (value: Parameters<NonNullable<KnownStatsPrinterFormatters[Key]>>[0], options: Required<KnownStatsPrinterColorFunctions> & StatsPrinterContextWithExtra, ...args: Tail<Parameters<NonNullable<KnownStatsPrinterFormatters[Key]>>>) => string }>} AvailableFormats */
 
 /** @type {AvailableFormats} */
 const AVAILABLE_FORMATS = {
@@ -1629,21 +1634,16 @@ class DefaultStatsPrinterPlugin {
 								context[color] = str => str;
 							}
 						}
-						for (const format of Object.keys(AVAILABLE_FORMATS)) {
+						for (const _format of Object.keys(AVAILABLE_FORMATS)) {
+							const format =
+								/** @type {keyof KnownStatsPrinterFormatters} */
+								(_format);
+
 							context[format] =
-								/**
-								 * @param {string | number} content content
-								 * @param {...TODO} args args
-								 * @returns {string} result
-								 */
+								/** @type {(content: Parameters<NonNullable<KnownStatsPrinterFormatters[keyof KnownStatsPrinterFormatters]>>[0], ...args: Tail<Parameters<NonNullable<KnownStatsPrinterFormatters[keyof KnownStatsPrinterFormatters]>>>) => string} */
 								(content, ...args) =>
 									/** @type {TODO} */
-									(
-										AVAILABLE_FORMATS[
-											/** @type {keyof AvailableFormats} */
-											(format)
-										]
-									)(
+									(AVAILABLE_FORMATS)[format](
 										content,
 										/** @type {StatsPrinterContext & Required<KnownStatsPrinterColorFunctions>} */
 										(context),

package.json

@@ -1,6 +1,6 @@
 {
   "name": "webpack",
-  "version": "5.99.8",
+  "version": "5.99.9",
   "author": "Tobias Koppers @sokra",
   "description": "Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.",
   "license": "MIT",

test/BenchmarkTestCases.benchmark.mjs

@@ -321,9 +321,10 @@ const baseOutputPath = path.join(__dirname, "js", "benchmark");
 
 const bench = withCodSpeed(
 	new Bench({
-		warmup: true,
 		now: hrtimeNow,
-		throws: true
+		throws: true,
+		warmup: true,
+		time: 30000
 	})
 );
 

test/configCases/parsing/dead-code-elimination-require-ensure/foo.js

@@ -0,0 +1 @@
+export default "foo"

test/configCases/parsing/dead-code-elimination-require-ensure/index.js

@@ -0,0 +1,14 @@
+it("should compile and work", done => {
+	require.ensure(
+		["./foo"],
+		() => {
+			throw new Error("error");
+		},
+		() => {
+			import("./foo").then(m => {
+				expect(m.default).toBe("foo");
+				done();
+			});
+		}
+	);
+});

test/configCases/parsing/dead-code-elimination-require-ensure/webpack.config.js

@@ -0,0 +1,6 @@
+/** @type {import("../../../../").Configuration} */
+module.exports = {
+	optimization: {
+		minimize: false
+	}
+};

test/configCases/parsing/dead-code-elimination/esm1.js

@@ -0,0 +1,18 @@
+it("Should eliminate hoisted function in ESM because of default strict mode", () => {
+	expect(() => {
+		fnDecl;
+	}).toThrow();
+	try {
+		throw new Error();
+	} catch (e) {
+		return;
+	}
+	{
+		function fnDecl() {
+			expect(true).toBe(true);
+		}
+	}
+	expect(true).toBe(false);
+});
+
+export default "esm1";

test/configCases/parsing/dead-code-elimination/esm2.js

@@ -0,0 +1 @@
+export default "esm2";