fix: allow to have any properties in `experiments` to prevent validation errors when an experiment is stable

declarations/WebpackOptions.d.ts

@@ -4042,6 +4042,7 @@ export interface ExperimentsExtra {
 	 * Compile entrypoints and import()s only when they are accessed.
 	 */
 	lazyCompilation?: boolean | LazyCompilationOptions;
+	[k: string]: any;
 }
 /**
  * Enables/Disables experiments (experimental features with relax SemVer compatibility).

schemas/WebpackOptions.json

@@ -965,7 +965,7 @@
       "description": "Enables/Disables experiments (experimental features with relax SemVer compatibility).",
       "type": "object",
       "implements": ["#/definitions/ExperimentsCommon"],
-      "additionalProperties": false,
+      "additionalProperties": true,
       "properties": {
         "asyncWebAssembly": {
           "description": "Support WebAssembly as asynchronous EcmaScript Module.",

test/Validation.test.js

@@ -51,6 +51,30 @@ describe("Validation", () => {
 		});
 	};
 
+	const createTestCaseWithoutError = (name, config, fn) => {
+		it(`should success validation for ${name}`, () => {
+			let errored;
+
+			try {
+				const webpack = require("..");
+
+				webpack(config);
+			} catch (err) {
+				if (err.name === "ValidationError") {
+					throw new Error("Validation didn't success");
+				}
+
+				errored = err;
+
+				return;
+			}
+
+			if (errored) {
+				throw new Error("Validation didn't success");
+			}
+		});
+	};
+
 	createTestCase("undefined configuration", undefined, (msg) =>
 		expect(msg).toMatchInlineSnapshot(`
 		"Invalid configuration object. Webpack has been initialized using a configuration object that does not match the API schema.
@@ -626,6 +650,10 @@ describe("Validation", () => {
 		`)
 	);
 
+	createTestCaseWithoutError("experiments", {
+		experiments: { unknown: true }
+	});
+
 	describe("did you mean", () => {
 		createTestCase(
 			"module.rules",
@@ -641,6 +669,7 @@ describe("Validation", () => {
 			   Did you mean module.rules?"
 		`)
 		);
+
 		createTestCase(
 			"optimization.splitChunks",
 			{
@@ -655,6 +684,7 @@ describe("Validation", () => {
 			   Did you mean optimization.splitChunks?"
 		`)
 		);
+
 		createTestCase(
 			"module.noParse",
 			{
@@ -669,6 +699,7 @@ describe("Validation", () => {
 			   Did you mean module.noParse?"
 		`)
 		);
+
 		createTestCase(
 			"optimization.moduleIds",
 			{
@@ -685,6 +716,7 @@ describe("Validation", () => {
 			   Did you mean optimization.moduleIds: \\"hashed\\" (BREAKING CHANGE since webpack 5)?"
 		`)
 		);
+
 		createTestCase(
 			"optimization.chunkIds",
 			{
@@ -701,6 +733,7 @@ describe("Validation", () => {
 			   Did you mean optimization.chunkIds: \\"named\\" (BREAKING CHANGE since webpack 5)?"
 		`)
 		);
+
 		createTestCase(
 			"optimization.chunk/moduleIds",
 			{
@@ -717,6 +750,7 @@ describe("Validation", () => {
 			   Did you mean optimization.chunkIds: \\"size\\" and optimization.moduleIds: \\"size\\" (BREAKING CHANGE since webpack 5)?"
 		`)
 		);
+
 		createTestCase(
 			"optimization.idHint",
 			{

types.d.ts

@@ -4903,6 +4903,8 @@ declare interface ExperimentsCommon {
  * Enables/Disables experiments (experimental features with relax SemVer compatibility).
  */
 declare interface ExperimentsExtra {
+	[index: string]: any;
+
 	/**
 	 * Build http(s): urls using a lockfile and resource content cache.
 	 */