fix(cjs): leaking implicit extension resolver

src/cjs/api/module-resolve-filename.ts

@@ -156,71 +156,69 @@ const resolveRequest = (
 export const createResolveFilename = (
 	nextResolve: ResolveFilename,
 	namespace?: string,
-): ResolveFilename => {
+): ResolveFilename => (
+	request,
+	parent,
+	isMain,
+	options,
+) => {
+	const resolve: SimpleResolve = request_ => nextResolve(
+		request_,
+		parent,
+		isMain,
+		options,
+	);
+
+	request = interopCjsExports(request);
+
+	if (parent?.filename) {
+		const filePath = getOriginalFilePath(parent.filename);
+		if (filePath) {
+			parent.filename = filePath.split('?')[0];
+		}
+	}
+
+	// Strip query string
+	const requestAndQuery = request.split('?');
+	const searchParams = new URLSearchParams(requestAndQuery[1]);
+
+	// Inherit parent namespace if it exists
+	if (parent?.filename) {
+		const parentQuery = new URLSearchParams(parent.filename.split('?')[1]);
+		const parentNamespace = parentQuery.get('namespace');
+		if (parentNamespace) {
+			searchParams.append('namespace', parentNamespace);
+		}
+	}
+
+	// If request namespace doesnt match the namespace, ignore
+	if ((searchParams.get('namespace') ?? undefined) !== namespace) {
+		return resolve(request);
+	}
+
 	if (namespace) {
 		/**
 		 * When namespaced, the loaders are registered to the extensions in a hidden way
 		 * so Node's built-in resolver will not try those extensions
 		 *
-		 * To support implicit extensions, we need to wrap the resolver with our own
+		 * To support implicit extensions, we need to enhance the resolver with our own
 		 * re-implementation of the implicit extension resolution
 		 */
 		nextResolve = createImplicitResolver(nextResolve);
 	}
 
-	return (
-		request,
-		parent,
-		isMain,
-		options,
-	) => {
-		const resolve: SimpleResolve = request_ => nextResolve(
-			request_,
-			parent,
-			isMain,
-			options,
-		);
-
-		request = interopCjsExports(request);
-
-		if (parent?.filename) {
-			const filePath = getOriginalFilePath(parent.filename);
-			if (filePath) {
-				parent.filename = filePath.split('?')[0];
-			}
-		}
-
-		// Strip query string
-		const requestAndQuery = request.split('?');
-		const searchParams = new URLSearchParams(requestAndQuery[1]);
+	let resolved = resolveRequest(requestAndQuery[0], parent, resolve);
 
-		// Inherit parent namespace if it exists
-		if (parent?.filename) {
-			const parentQuery = new URLSearchParams(parent.filename.split('?')[1]);
-			const parentNamespace = parentQuery.get('namespace');
-			if (parentNamespace) {
-				searchParams.append('namespace', parentNamespace);
-			}
-		}
-
-		// If request namespace doesnt match the namespace, ignore
-		if ((searchParams.get('namespace') ?? undefined) !== namespace) {
-			return resolve(request);
-		}
-
-		let resolved = resolveRequest(requestAndQuery[0], parent, resolve);
-
-		// Only add query back if it's a file path (not a core Node module)
-		if (
-			path.isAbsolute(resolved)
+	// Only add query back if it's a file path (not a core Node module)
+	if (
+		path.isAbsolute(resolved)
 
 			// These two have native loaders which don't support queries
 			&& !resolved.endsWith('.json')
 			&& !resolved.endsWith('.node')
-		) {
-			resolved += urlSearchParamsStringify(searchParams);
-		}
+	) {
+		resolved += urlSearchParamsStringify(searchParams);
+	}
 
-		return resolved;
-	};
+	return resolved;
 };

src/cjs/api/resolve-implicit-extensions.ts

@@ -1,5 +1,6 @@
 import path from 'node:path';
 import type { NodeError } from '../../types.js';
+import { isBarePackageNamePattern } from '../../utils/path-utils.js';
 import type { ResolveFilename } from './types.js';
 
 export const implicitlyResolvableExtensions = [
@@ -34,6 +35,7 @@ export const createImplicitResolver = (
 		const nodeError = _error as NodeError;
 		if (
 			nodeError.code === 'MODULE_NOT_FOUND'
+			&& !isBarePackageNamePattern.test(request)
 		) {
 			const resolved = (
 				tryExtensions(resolve, request, ...args)

src/utils/path-utils.ts

@@ -53,4 +53,5 @@ export const isJsonPattern = /\.json($|\?)/;
 export const isDirectoryPattern = /\/(?:$|\?)/;
 
 // Only matches packages names without subpaths (e.g. `foo` but not `foo/bar`)
-export const isBarePackageNamePattern = /^(?:@[^/]+\/)?[^/]+$/;
+// Back slash included to exclude Windows paths
+export const isBarePackageNamePattern = /^(?:@[^/]+\/)?[^/\\]+$/;

tests/specs/api.ts

@@ -135,42 +135,84 @@ export default testSuite(({ describe }, node: NodeApis) => {
 				expect(stdout).toBe('js working\nts working');
 			});
 
-			test('register / unregister', async () => {
-				await using fixture = await createFixture({
-					'register.cjs': `
-					const { register } = require(${JSON.stringify(tsxCjsApiPath)});
-					try {
-						require('./file');
-					} catch {
-						console.log('Fails as expected');
-					}
-
-					const unregister = register();
-
-					const loaded = require('./file');
-					console.log(loaded.message);
-
-					// Remove from cache
-					const loadedPath = require.resolve('./file');
-					delete require.cache[loadedPath];
-
-					unregister();
-
-					try {
-						require('./file');
-					} catch {
-						console.log('Unregistered');
-					}
-					`,
-					...tsFiles,
-				});
+			describe('register', ({ test }) => {
+				test('register / unregister', async () => {
+					await using fixture = await createFixture({
+						'register.cjs': `
+						const { register } = require(${JSON.stringify(tsxCjsApiPath)});
+						try {
+							require('./file');
+						} catch {
+							console.log('Fails as expected');
+						}
+	
+						const unregister = register();
+	
+						const loaded = require('./file');
+						console.log(loaded.message);
+	
+						// Remove from cache
+						const loadedPath = require.resolve('./file');
+						delete require.cache[loadedPath];
+	
+						unregister();
+	
+						try {
+							require('./file');
+						} catch {
+							console.log('Unregistered');
+						}
+						`,
+						...tsFiles,
+					});
 
-				const { stdout } = await execaNode(fixture.getPath('register.cjs'), [], {
-					nodePath: node.path,
-					nodeOptions: [],
+					const { stdout } = await execaNode(fixture.getPath('register.cjs'), [], {
+						nodePath: node.path,
+						nodeOptions: [],
+					});
+
+					expect(stdout).toBe('Fails as expected\nfoo bar json file.ts\nUnregistered');
 				});
 
-				expect(stdout).toBe('Fails as expected\nfoo bar json file.ts\nUnregistered');
+				test('namespace', async () => {
+					await using fixture = await createFixture({
+						'require.cjs': `
+						const { expectErrors } = require('expect-errors');
+						const path = require('node:path');
+						const tsx = require(${JSON.stringify(tsxCjsApiPath)});
+
+						const api = tsx.register({ namespace: 'abcd' });
+
+						expectErrors(
+							// Loading explicit/resolved file path should be ignored by loader (extensions)
+							[() => require('./file.ts'), 'SyntaxError'],
+
+							// resolver should preserve full file path when ignoring
+							[() => require('./file.ts?asdf'), "Cannot find module './file.ts?asdf'"]
+						);
+
+						const { message, async } = api.require('./file', __filename);
+						console.log(message);
+						async.then(m => console.log(m.default));
+
+						api.require('./tsx?query=1', __filename);
+						api.require('./jsx', __filename);
+						api.require('./dir?query=3', __filename);
+						`,
+						...tsFiles,
+
+						'tsx.tsx': 'console.log(\'tsx\');',
+						'jsx.jsx': 'console.log(\'jsx\');',
+						'dir/index.jsx': 'console.log(\'dir\');',
+					});
+
+					const { stdout } = await execaNode(fixture.getPath('require.cjs'), [], {
+						nodePath: node.path,
+						nodeOptions: [],
+					});
+
+					expect(stdout).toBe('foo bar json file.ts\ntsx\njsx\ndir\nasync');
+				});
 			});
 
 			describe('tsx.require()', ({ test }) => {
@@ -265,46 +307,6 @@ export default testSuite(({ describe }, node: NodeApis) => {
 
 					expect(stdout).toBe('foo bar json file.ts\nfoo bar json file.ts\nfoo bar json file.ts\nUnregistered');
 				});
-
-				test('namespace', async () => {
-					await using fixture = await createFixture({
-						'require.cjs': `
-						const { expectErrors } = require('expect-errors');
-						const path = require('node:path');
-						const tsx = require(${JSON.stringify(tsxCjsApiPath)});
-
-						const api = tsx.register({ namespace: 'abcd' });
-
-						expectErrors(
-							// Loading explicit/resolved file path should be ignored by loader (extensions)
-							[() => require('./file.ts'), 'SyntaxError'],
-
-							// resolver should preserve full file path when ignoring
-							[() => require('./file.ts?asdf'), "Cannot find module './file.ts?asdf'"]
-						);
-
-						const { message, async } = api.require('./file', __filename);
-						console.log(message);
-						async.then(m => console.log(m.default));
-
-						api.require('./tsx?query=1', __filename);
-						api.require('./jsx', __filename);
-						api.require('./dir?query=3', __filename);
-						`,
-						...tsFiles,
-
-						'tsx.tsx': 'console.log(\'tsx\');',
-						'jsx.jsx': 'console.log(\'jsx\');',
-						'dir/index.jsx': 'console.log(\'dir\');',
-					});
-
-					const { stdout } = await execaNode(fixture.getPath('require.cjs'), [], {
-						nodePath: node.path,
-						nodeOptions: [],
-					});
-
-					expect(stdout).toBe('foo bar json file.ts\ntsx\njsx\ndir\nasync');
-				});
 			});
 		});