node-api: reject detaching immutable arraybuffers

src/js_native_api_v8.cc

@@ -3724,8 +3724,9 @@ napi_status NAPI_CDECL napi_detach_arraybuffer(napi_env env,
       env, value->IsArrayBuffer(), napi_arraybuffer_expected);
 
   v8::Local<v8::ArrayBuffer> it = value.As<v8::ArrayBuffer>();
-  RETURN_STATUS_IF_FALSE(
-      env, it->IsDetachable(), napi_detachable_arraybuffer_expected);
+  RETURN_STATUS_IF_FALSE(env,
+                         it->IsDetachable() && !it->IsImmutable(),
+                         napi_detachable_arraybuffer_expected);
 
   it->Detach(v8::Local<v8::Value>()).Check();
 

test/js-native-api/test_typedarray/test-detach-immutable.js

@@ -0,0 +1,25 @@
+// Flags: --js-immutable-arraybuffer
+'use strict';
+
+const common = require('../../common');
+const assert = require('assert');
+const binding = require(`./build/${common.buildType}/test_typedarray`);
+
+for (const bytes of [[1, 2, 3, 4], []]) {
+  const buffer = Uint8Array.from(bytes).buffer.transferToImmutable();
+  const view = new Uint8Array(buffer);
+
+  assert.throws(() => binding.Detach(view), {
+    name: 'Error',
+    message: 'A detachable arraybuffer was expected',
+  });
+  assert.strictEqual(binding.IsDetached(buffer), false);
+  assert.strictEqual(buffer.immutable, true);
+  assert.strictEqual(view.byteLength, bytes.length);
+  assert.deepStrictEqual([...view], bytes);
+
+  const mutable = Uint8Array.from(bytes);
+  binding.Detach(mutable);
+  assert.strictEqual(binding.IsDetached(mutable.buffer), true);
+  assert.strictEqual(mutable.byteLength, 0);
+}