fix: handle nameless blocks in class bodies

lib/transforms.js

@@ -188,7 +188,9 @@ function traceInstanceMethod (state, node, program) {
 
   // If the method exists on the class, we return as it will be patched later
   // while traversing child nodes later on.
-  if (classBody.body.some(({ key }) => key.name === methodName)) return
+  // `key` is absent on members without one (e.g. ES2022 `static {}` blocks),
+  // so guard against reading `.name` on undefined.
+  if (classBody.body.some(({ key }) => key?.name === methodName)) return
 
   // Method doesn't exist on the class so we assume an instance method and
   // wrap it in the constructor instead.

tests/static_block_cjs/mod.js

@@ -0,0 +1,18 @@
+/**
+ * Unless explicitly stated otherwise all files in this repository are licensed under the Apache-2.0 License.
+ * This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2025 Datadog, Inc.
+ **/
+class UndiciBase {
+  async fetch (url) {
+    return 42
+  }
+}
+class Undici extends UndiciBase {
+  static { this.KIND = 'undici' }
+  static { this.VERSION = 1 }
+  async fetch (url) {
+    return super.fetch(url)
+  }
+}
+
+module.exports = Undici

tests/static_block_cjs/test.js

@@ -0,0 +1,21 @@
+/**
+ * Unless explicitly stated otherwise all files in this repository are licensed under the Apache-2.0 License.
+ * This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2025 Datadog, Inc.
+ **/
+const Undici = require('./instrumented.js')
+const { assert, getContext } = require('../common/preamble.js')
+const context = getContext('orchestrion:undici:Undici:fetch');
+(async () => {
+  // Static init blocks are preserved and still run.
+  assert.strictEqual(Undici.KIND, 'undici')
+  assert.strictEqual(Undici.VERSION, 1)
+  const undici = new Undici()
+  const result = await undici.fetch('https://example.com')
+  assert.strictEqual(result, 42)
+  assert.deepStrictEqual(context, {
+    start: true,
+    end: true,
+    asyncStart: 42,
+    asyncEnd: 42
+  })
+})()

tests/tests.test.mjs

@@ -89,6 +89,18 @@ describe('class_method_cjs', () => {
   })
 })
 
+describe('static_block_cjs', () => {
+  test('instruments class method when class body has static init blocks', () => {
+    runTest('static_block_cjs', [
+      {
+        channelName: 'Undici:fetch',
+        module: { name: TEST_MODULE_NAME, versionRange: '>=0.0.1', filePath: TEST_MODULE_PATH },
+        functionQuery: { className: 'Undici', methodName: 'fetch', kind: 'Async' },
+      },
+    ])
+  })
+})
+
 describe('constructor_cjs', () => {
   test('instruments class constructor (cjs)', () => {
     runTest('constructor_cjs', [