fix #3001: EINVAL => ENOTDIR for readdir

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+* Work around an issue with `NODE_PATH` and Go's WebAssembly internals ([#3001](https://github.com/evanw/esbuild/issues/3001))
+
+    Go's WebAssembly implementation returns `EINVAL` instead of `ENOTDIR` when using the `readdir` syscall on a file. This messes up esbuild's implementation of node's module resolution algorithm since encountering `ENOTDIR` causes esbuild to continue its search (since it's a normal condition) while other encountering other errors causes esbuild to fail with an I/O error (since it's an unexpected condition). You can encounter this issue in practice if you use node's legacy `NODE_PATH` feature to tell esbuild to resolve node modules in a custom directory that was not installed by npm. This release works around this problem by converting `EINVAL` into `ENOTDIR` for the `readdir` syscall.
+
 ## 0.17.12
 
 * Fix a crash when parsing inline TypeScript decorators ([#2991](https://github.com/evanw/esbuild/issues/2991))

internal/fs/fs_real.go

@@ -360,6 +360,14 @@ func (fs *realFS) readdir(dirname string) (entries []string, canonicalError erro
 	// Don't convert ENOTDIR to ENOENT here. ENOTDIR is a legitimate error
 	// condition for Readdirnames() on non-Windows platforms.
 
+	// Go's WebAssembly implementation returns EINVAL instead of ENOTDIR if we
+	// call "readdir" on a file. Canonicalize this to ENOTDIR so esbuild's path
+	// resolution code continues traversing instead of failing with an error.
+	// https://github.com/golang/go/blob/2449bbb5e614954ce9e99c8a481ea2ee73d72d61/src/syscall/fs_js.go#L144
+	if pathErr, ok := canonicalError.(*os.PathError); ok && pathErr.Unwrap() == syscall.EINVAL {
+		canonicalError = syscall.ENOTDIR
+	}
+
 	return entries, canonicalError, originalError
 }
 

scripts/wasm-tests.js

@@ -324,6 +324,26 @@ const tests = {
 })();
 `)
   },
+
+  // https://github.com/evanw/esbuild/issues/3001
+  nodePathsReaddirEINVAL({ testDir, esbuildPathWASM }) {
+    const libDir = path.join(testDir, 'lib');
+    const libFile = path.join(libDir, 'file.js');
+    fs.mkdirSync(libDir, { recursive: true });
+    fs.writeFileSync(libFile, 'foo()');
+    const stdout = child_process.execFileSync('node', [
+      esbuildPathWASM,
+      '--bundle',
+      '--format=esm',
+    ], {
+      stdio: ['pipe', 'pipe', 'inherit'],
+      cwd: testDir,
+      input: `import "file.js"`,
+      env: { ...process.env, NODE_PATH: libDir },
+    }).toString();
+
+    assert.deepStrictEqual(stdout, '// lib/file.js\nfoo();\n');
+  },
 };
 
 function runTest({ testDir, esbuildPathNative, esbuildPathWASM, test }) {