fix(tsconfig): detect circular extends to prevent infinite loop (#477)

Author: xiaoxiaojx

lib/TsconfigPathsPlugin.js

@@ -413,13 +413,15 @@ module.exports = class TsconfigPathsPlugin {
 	 * @param {string} configFilePath current config file path
 	 * @param {string} extendedConfigValue extends value
 	 * @param {Set<string>} fileDependencies the file dependencies
+	 * @param {Set<string>} visitedConfigPaths config paths being loaded (for circular extends detection)
 	 * @returns {Promise<Tsconfig>} the extended tsconfig
 	 */
 	async _loadTsconfigFromExtends(
 		fileSystem,
 		configFilePath,
 		extendedConfigValue,
 		fileDependencies,
+		visitedConfigPaths,
 	) {
 		const currentDir = dirname(configFilePath);
 
@@ -451,6 +453,7 @@ module.exports = class TsconfigPathsPlugin {
 			fileSystem,
 			extendedConfigPath,
 			fileDependencies,
+			visitedConfigPaths,
 		);
 		const compilerOptions = config.compilerOptions || { baseUrl: undefined };
 
@@ -527,9 +530,19 @@ module.exports = class TsconfigPathsPlugin {
 	 * @param {FileSystem} fileSystem the file system
 	 * @param {string} configFilePath absolute path to tsconfig.json
 	 * @param {Set<string>} fileDependencies the file dependencies
+	 * @param {Set<string>=} visitedConfigPaths config paths being loaded (for circular extends detection)
 	 * @returns {Promise<Tsconfig>} the merged tsconfig
 	 */
-	async _loadTsconfig(fileSystem, configFilePath, fileDependencies) {
+	async _loadTsconfig(
+		fileSystem,
+		configFilePath,
+		fileDependencies,
+		visitedConfigPaths = new Set(),
+	) {
+		if (visitedConfigPaths.has(configFilePath)) {
+			return /** @type {Tsconfig} */ ({});
+		}
+		visitedConfigPaths.add(configFilePath);
 		const config = await readJson(fileSystem, configFilePath);
 		fileDependencies.add(configFilePath);
 
@@ -547,6 +560,7 @@ module.exports = class TsconfigPathsPlugin {
 						configFilePath,
 						extendedConfigElement,
 						fileDependencies,
+						visitedConfigPaths,
 					);
 					base = mergeTsconfigs(base, extendedTsconfig);
 				}
@@ -556,6 +570,7 @@ module.exports = class TsconfigPathsPlugin {
 					configFilePath,
 					extendedConfig,
 					fileDependencies,
+					visitedConfigPaths,
 				);
 			}
 

test/fixtures/tsconfig-paths/extends-circular/a/src/lib/foo.ts

@@ -0,0 +1,2 @@
+export const foo = "foo";
+

test/fixtures/tsconfig-paths/extends-circular/a/tsconfig.json

@@ -0,0 +1,10 @@
+{
+	"extends": "${configDir}/../b/tsconfig",
+	"compilerOptions": {
+		"baseUrl": ".",
+		"paths": {
+			"@lib/*": ["${configDir}/src/lib/*"]
+		}
+	}
+}
+

test/fixtures/tsconfig-paths/extends-circular/b/src/util/bar.ts

@@ -0,0 +1,2 @@
+export const bar = "bar";
+

test/fixtures/tsconfig-paths/extends-circular/b/tsconfig.json

@@ -0,0 +1,10 @@
+{
+	"extends": "${configDir}/../a/tsconfig",
+	"compilerOptions": {
+		"baseUrl": ".",
+		"paths": {
+			"@util/*": ["${configDir}/src/util/*"]
+		}
+	}
+}
+

test/tsconfig-paths.test.js

@@ -26,6 +26,12 @@ const extendsNpmDir = path.resolve(
 	"tsconfig-paths",
 	"extends-npm",
 );
+const extendsCircularDir = path.resolve(
+	__dirname,
+	"fixtures",
+	"tsconfig-paths",
+	"extends-circular",
+);
 const referencesProjectDir = path.resolve(
 	__dirname,
 	"fixtures",
@@ -547,6 +553,25 @@ describe("TsconfigPathsPlugin", () => {
 			);
 		});
 
+		it("should handle circular extends without hanging", (done) => {
+			const aDir = path.join(extendsCircularDir, "a");
+			const resolver = ResolverFactory.createResolver({
+				fileSystem,
+				extensions: [".ts", ".tsx"],
+				mainFields: ["browser", "main"],
+				mainFiles: ["index"],
+				tsconfig: path.join(aDir, "tsconfig.json"),
+			});
+
+			// a extends b, b extends a - circular. Should break cycle and resolve.
+			resolver.resolve({}, aDir, "@lib/foo", {}, (err, result) => {
+				if (err) return done(err);
+				if (!result) return done(new Error("No result"));
+				expect(result).toEqual(path.join(aDir, "src", "lib", "foo.ts"));
+				done();
+			});
+		});
+
 		// eslint-disable-next-line no-template-curly-in-string
 		it("should substitute ${configDir} in references field", (done) => {
 			const sharedDir = path.join(referencesProjectDir, "packages", "shared");