refactor: Remove eslintrc from flat config functionality (#19833)

nzakas · fasttime · web-flow · commit a806994263e5 · 2025-06-10T19:04:03.000+02:00
* refactor: Remove eslintrc from flat config functionality

* Fix knip error

* Fix knip again

* Update lib/shared/relative-module-resolver.js

Co-authored-by: Francesco Trotta &lt;github@fasttime.org&gt;

* Remove unused file

---------

Co-authored-by: Francesco Trotta &lt;github@fasttime.org&gt;
diff --git a/lib/cli.js b/lib/cli.js
@@ -28,13 +28,14 @@ const fs = require("node:fs"),
 	log = require("./shared/logging"),
 	RuntimeInfo = require("./shared/runtime-info"),
 	{ normalizeSeverityToString } = require("./shared/severity");
-const {
-	Legacy: { naming },
-} = require("@eslint/eslintrc");
 const { ModuleImporter } = require("@humanwhocodes/module-importer");
 const { getCacheFile } = require("./eslint/eslint-helpers");
 const { SuppressionsService } = require("./services/suppressions-service");
 const debug = require("debug")("eslint:cli");
+const {
+	normalizePackageName,
+	getShorthandName,
+} = require("./shared/naming.js");
 
 //------------------------------------------------------------------------------
 // Types
@@ -67,10 +68,7 @@ async function loadPlugins(importer, pluginNames) {
 
 	await Promise.all(
 		pluginNames.map(async pluginName => {
-			const longName = naming.normalizePackageName(
-				pluginName,
-				"eslint-plugin",
-			);
+			const longName = normalizePackageName(pluginName, "eslint-plugin");
 			const module = await importer.import(longName);
 
 			if (!("default" in module)) {
@@ -79,10 +77,7 @@ async function loadPlugins(importer, pluginNames) {
 				);
 			}
 
-			const shortName = naming.getShorthandName(
-				pluginName,
-				"eslint-plugin",
-			);
+			const shortName = getShorthandName(pluginName, "eslint-plugin");
 
 			plugins[shortName] = module.default;
 		}),
diff --git a/lib/eslint/eslint.js b/lib/eslint/eslint.js
@@ -15,13 +15,6 @@ const path = require("node:path");
 const { version } = require("../../package.json");
 const { Linter } = require("../linter");
 const { defaultConfig } = require("../config/default-config");
-const {
-	Legacy: {
-		ConfigOps: { getRuleSeverity },
-		ModuleResolver,
-		naming,
-	},
-} = require("@eslint/eslintrc");
 
 const {
 	findFiles,
@@ -41,6 +34,13 @@ const LintResultCache = require("../cli-engine/lint-result-cache");
 const { Retrier } = require("@humanwhocodes/retry");
 const { ConfigLoader, LegacyConfigLoader } = require("../config/config-loader");
 const { WarningService } = require("../services/warning-service");
+const { Config } = require("../config/config.js");
+const {
+	getShorthandName,
+	getNamespaceFromTerm,
+	normalizePackageName,
+} = require("../shared/naming.js");
+const { resolve } = require("../shared/relative-module-resolver.js");
 
 /*
  * This is necessary to allow overwriting writeFile for testing purposes.
@@ -160,7 +160,7 @@ function getOrFindUsedDeprecatedRules(eslint, maybeFilePath) {
 
 		if (config.rules) {
 			for (const [ruleId, ruleConf] of Object.entries(config.rules)) {
-				if (getRuleSeverity(ruleConf) === 0) {
+				if (Config.getRuleNumericSeverity(ruleConf) === 0) {
 					continue;
 				}
 				const rule = config.getRuleDefinition(ruleId);
@@ -174,7 +174,7 @@ function getOrFindUsedDeprecatedRules(eslint, maybeFilePath) {
 						replacedBy: usesNewFormat
 							? (meta.deprecated.replacedBy?.map(
 									replacement =>
-										`${replacement.plugin?.name !== void 0 ? `${naming.getShorthandName(replacement.plugin.name, "eslint-plugin")}/` : ""}${replacement.rule?.name ?? ""}`,
+										`${replacement.plugin?.name !== void 0 ? `${getShorthandName(replacement.plugin.name, "eslint-plugin")}/` : ""}${replacement.rule?.name ?? ""}`,
 								) ?? [])
 							: meta.replacedBy || [],
 						info: usesNewFormat ? meta.deprecated : void 0,
@@ -489,8 +489,7 @@ class ESLint {
 			for (const [pluginName, plugin] of Object.entries(
 				options.plugins,
 			)) {
-				plugins[naming.getShorthandName(pluginName, "eslint-plugin")] =
-					plugin;
+				plugins[getShorthandName(pluginName, "eslint-plugin")] = plugin;
 			}
 
 			defaultConfigs.push({
@@ -998,7 +997,7 @@ class ESLint {
 
 		// replace \ with / for Windows compatibility
 		const normalizedFormatName = name.replace(/\\/gu, "/");
-		const namespace = naming.getNamespaceFromTerm(normalizedFormatName);
+		const namespace = getNamespaceFromTerm(normalizedFormatName);
 
 		// grab our options
 		const { cwd } = privateMembers.get(this).options;
@@ -1010,16 +1009,13 @@ class ESLint {
 			formatterPath = path.resolve(cwd, normalizedFormatName);
 		} else {
 			try {
-				const npmFormat = naming.normalizePackageName(
+				const npmFormat = normalizePackageName(
 					normalizedFormatName,
 					"eslint-formatter",
 				);
 
 				// TODO: This is pretty dirty...would be nice to clean up at some point.
-				formatterPath = ModuleResolver.resolve(
-					npmFormat,
-					getPlaceholderPath(cwd),
-				);
+				formatterPath = resolve(npmFormat, getPlaceholderPath(cwd));
 			} catch {
 				formatterPath = path.resolve(
 					__dirname,
diff --git a/lib/linter/apply-disable-directives.js b/lib/linter/apply-disable-directives.js
@@ -19,9 +19,7 @@
 //------------------------------------------------------------------------------
 
 const escapeRegExp = require("escape-string-regexp");
-const {
-	Legacy: { ConfigOps },
-} = require("@eslint/eslintrc/universal");
+const { Config } = require("../config/config.js");
 
 /**
  * Compares the locations of two objects in a source file
@@ -539,7 +537,7 @@ module.exports = ({
 		configuredRules && ruleFilter
 			? new Set(
 					Object.keys(configuredRules).filter(ruleId => {
-						const severity = ConfigOps.getRuleSeverity(
+						const severity = Config.getRuleNumericSeverity(
 							configuredRules[ruleId],
 						);
 
diff --git a/lib/shared/naming.js b/lib/shared/naming.js
@@ -0,0 +1,109 @@
+/**
+ * @fileoverview Common helpers for naming of plugins, formatters and configs
+ */
+
+"use strict";
+
+const NAMESPACE_REGEX = /^@.*\//iu;
+
+/**
+ * Brings package name to correct format based on prefix
+ * @param {string} name The name of the package.
+ * @param {string} prefix Can be either "eslint-plugin", "eslint-config" or "eslint-formatter"
+ * @returns {string} Normalized name of the package
+ * @private
+ */
+function normalizePackageName(name, prefix) {
+	let normalizedName = name;
+
+	/**
+	 * On Windows, name can come in with Windows slashes instead of Unix slashes.
+	 * Normalize to Unix first to avoid errors later on.
+	 * https://github.com/eslint/eslint/issues/5644
+	 */
+	if (normalizedName.includes("\\")) {
+		normalizedName = normalizedName.replace(/\\/gu, "/");
+	}
+
+	if (normalizedName.charAt(0) === "@") {
+		/**
+		 * it's a scoped package
+		 * package name is the prefix, or just a username
+		 */
+		const scopedPackageShortcutRegex = new RegExp(
+				`^(@[^/]+)(?:/(?:${prefix})?)?$`,
+				"u",
+			),
+			scopedPackageNameRegex = new RegExp(`^${prefix}(-|$)`, "u");
+
+		if (scopedPackageShortcutRegex.test(normalizedName)) {
+			normalizedName = normalizedName.replace(
+				scopedPackageShortcutRegex,
+				`$1/${prefix}`,
+			);
+		} else if (!scopedPackageNameRegex.test(normalizedName.split("/")[1])) {
+			/**
+			 * for scoped packages, insert the prefix after the first / unless
+			 * the path is already @scope/eslint or @scope/eslint-xxx-yyy
+			 */
+			normalizedName = normalizedName.replace(
+				/^@([^/]+)\/(.*)$/u,
+				`@$1/${prefix}-$2`,
+			);
+		}
+	} else if (!normalizedName.startsWith(`${prefix}-`)) {
+		normalizedName = `${prefix}-${normalizedName}`;
+	}
+
+	return normalizedName;
+}
+
+/**
+ * Removes the prefix from a fullname.
+ * @param {string} fullname The term which may have the prefix.
+ * @param {string} prefix The prefix to remove.
+ * @returns {string} The term without prefix.
+ */
+function getShorthandName(fullname, prefix) {
+	if (fullname[0] === "@") {
+		let matchResult = new RegExp(`^(@[^/]+)/${prefix}$`, "u").exec(
+			fullname,
+		);
+
+		if (matchResult) {
+			return matchResult[1];
+		}
+
+		matchResult = new RegExp(`^(@[^/]+)/${prefix}-(.+)$`, "u").exec(
+			fullname,
+		);
+		if (matchResult) {
+			return `${matchResult[1]}/${matchResult[2]}`;
+		}
+	} else if (fullname.startsWith(`${prefix}-`)) {
+		return fullname.slice(prefix.length + 1);
+	}
+
+	return fullname;
+}
+
+/**
+ * Gets the scope (namespace) of a term.
+ * @param {string} term The term which may have the namespace.
+ * @returns {string} The namespace of the term if it has one.
+ */
+function getNamespaceFromTerm(term) {
+	const match = term.match(NAMESPACE_REGEX);
+
+	return match ? match[0] : "";
+}
+
+//------------------------------------------------------------------------------
+// Public Interface
+//------------------------------------------------------------------------------
+
+module.exports = {
+	normalizePackageName,
+	getShorthandName,
+	getNamespaceFromTerm,
+};
diff --git a/lib/shared/relative-module-resolver.js b/lib/shared/relative-module-resolver.js
@@ -0,0 +1,28 @@
+/**
+ * Utility for resolving a module relative to another module
+ * @author Teddy Katz
+ */
+
+"use strict";
+
+const Module = require("node:module");
+
+/*
+ * `Module.createRequire` is added in v12.2.0. It supports URL as well.
+ * We only support the case where the argument is a filepath, not a URL.
+ */
+const createRequire = Module.createRequire;
+
+/**
+ * Resolves a Node module relative to another module
+ * @param {string} moduleName The name of a Node module, or a path to a Node module.
+ * @param {string} relativeToPath An absolute path indicating the module that `moduleName` should be resolved relative to. This must be
+ * a file rather than a directory, but the file need not actually exist.
+ * @returns {string} The absolute path that would result from calling `require.resolve(moduleName)` in a file located at `relativeToPath`
+ * @throws {Error} When the module cannot be resolved.
+ */
+function resolve(moduleName, relativeToPath) {
+	return createRequire(relativeToPath).resolve(moduleName);
+}
+
+exports.resolve = resolve;
diff --git a/package.json b/package.json
@@ -176,7 +176,7 @@
     "jiti": "^2.2.0",
     "jiti-v2.0": "npm:jiti@2.0.x",
     "jiti-v2.1": "npm:jiti@2.1.x",
-    "knip": "^5.32.0",
+    "knip": "^5.60.2",
     "lint-staged": "^11.0.0",
     "load-perf": "^0.2.0",
     "markdown-it": "^12.2.0",
diff --git a/tests/fixtures/relative-module-resolver/file2.js b/tests/fixtures/relative-module-resolver/file2.js
diff --git a/tests/lib/shared/naming.js b/tests/lib/shared/naming.js
@@ -0,0 +1,66 @@
+/**
+ * @fileoverview Tests for naming util
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const { assert } = require("chai");
+const naming = require("../../../lib/shared/naming.js");
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+describe("naming", () => {
+	describe("normalizePackageName()", () => {
+		[
+			["foo", "eslint-config-foo"],
+			["eslint-config-foo", "eslint-config-foo"],
+			["@z/foo", "@z/eslint-config-foo"],
+			["@z\\foo", "@z/eslint-config-foo"],
+			["@z\\foo\\bar.js", "@z/eslint-config-foo/bar.js"],
+			["@z/eslint-config", "@z/eslint-config"],
+			["@z/eslint-config-foo", "@z/eslint-config-foo"],
+		].forEach(([input, expected]) => {
+			it(`should return ${expected} when passed ${input}`, () => {
+				const result = naming.normalizePackageName(
+					input,
+					"eslint-config",
+				);
+
+				assert.strictEqual(result, expected);
+			});
+		});
+	});
+
+	describe("getShorthandName()", () => {
+		[
+			["foo", "foo"],
+			["eslint-config-foo", "foo"],
+			["@z", "@z"],
+			["@z/eslint-config", "@z"],
+			["@z/foo", "@z/foo"],
+			["@z/eslint-config-foo", "@z/foo"],
+		].forEach(([input, expected]) => {
+			it(`should return ${expected} when passed ${input}`, () => {
+				const result = naming.getShorthandName(input, "eslint-config");
+
+				assert.strictEqual(result, expected);
+			});
+		});
+	});
+
+	describe("getNamespaceFromTerm()", () => {
+		it("should remove namespace when passed with namespace", () => {
+			const namespace = naming.getNamespaceFromTerm(
+				"@namespace/eslint-plugin-test",
+			);
+
+			assert.strictEqual(namespace, "@namespace/");
+		});
+	});
+});
diff --git a/tests/lib/shared/relative-module-resolver.js b/tests/lib/shared/relative-module-resolver.js
@@ -0,0 +1,27 @@
+/**
+ * @fileoverview Tests for relative module resolver.
+ */
+
+"use strict";
+
+const { assert } = require("chai");
+const path = require("node:path");
+const ModuleResolver = require("../../../lib/shared/relative-module-resolver.js");
+
+describe("ModuleResolver", () => {
+	describe("resolve()", () => {
+		it("should correctly resolve a relative path", () => {
+			assert.strictEqual(
+				ModuleResolver.resolve(
+					"./file2.js",
+					path.resolve(
+						"./tests/fixtures/relative-module-resolver/file.js",
+					),
+				),
+				path.resolve(
+					"./tests/fixtures/relative-module-resolver/file2.js",
+				),
+			);
+		});
+	});
+});
