ffi: throw on missing memory helper arguments

src/ffi/data.cc

@@ -163,8 +163,7 @@ Maybe<void> ValidateStringLength(Environment* env, size_t len) {
 Maybe<std::pair<uint8_t*, size_t>> GetValidatedPointerAndOffset(
     Environment* env, const FunctionCallbackInfo<Value>& args) {
   uintptr_t raw_ptr;
-  if (args.Length() < 1 ||
-      !GetValidatedPointerAddress(env, args[0], "pointer").To(&raw_ptr)) {
+  if (!GetValidatedPointerAddress(env, args[0], "pointer").To(&raw_ptr)) {
     return {};
   }
 
@@ -204,8 +203,7 @@ Maybe<PointerOffsetAndValue> GetValidatedPointerOffsetAndValue(
   size_t offset;
   Local<Value> value;
   uintptr_t raw_ptr;
-  if (args.Length() < 1 ||
-      !GetValidatedPointerAddress(env, args[0], "pointer").To(&raw_ptr)) {
+  if (!GetValidatedPointerAddress(env, args[0], "pointer").To(&raw_ptr)) {
     return {};
   }
 
@@ -556,7 +554,7 @@ void ToBuffer(const FunctionCallbackInfo<Value>& args) {
   }
 
   size_t len;
-  if (args.Length() < 2 || !GetValidatedSize(env, args[1], "length").To(&len)) {
+  if (!GetValidatedSize(env, args[1], "length").To(&len)) {
     return;
   }
 
@@ -618,7 +616,7 @@ void ToArrayBuffer(const FunctionCallbackInfo<Value>& args) {
   }
 
   size_t len;
-  if (args.Length() < 2 || !GetValidatedSize(env, args[1], "length").To(&len)) {
+  if (!GetValidatedSize(env, args[1], "length").To(&len)) {
     return;
   }
 
@@ -694,13 +692,12 @@ void ExportBytes(const FunctionCallbackInfo<Value>& args) {
   }
 
   uintptr_t ptr;
-  if (args.Length() < 2 ||
-      !GetValidatedPointerAddress(env, args[1], "pointer").To(&ptr)) {
+  if (!GetValidatedPointerAddress(env, args[1], "pointer").To(&ptr)) {
     return;
   }
 
   size_t len;
-  if (args.Length() < 3 || !GetValidatedSize(env, args[2], "length").To(&len)) {
+  if (!GetValidatedSize(env, args[2], "length").To(&len)) {
     return;
   }
 

test/ffi/test-ffi-memory.js

@@ -319,3 +319,23 @@ test('ffi validates memory access arguments', () => {
     }
   }));
 });
+
+test('ffi memory helpers reject missing required arguments', () => {
+  const widths = ['Int8', 'Uint8', 'Int16', 'Uint16', 'Int32', 'Uint32',
+                  'Int64', 'Uint64', 'Float32', 'Float64'];
+
+  // Calling a helper with no arguments must report the missing pointer the
+  // same way an explicitly passed `undefined` does, instead of returning
+  // `undefined` as if the read or the write had succeeded.
+  for (const width of widths) {
+    for (const name of [`get${width}`, `set${width}`]) {
+      assert.throws(() => ffi[name](), /The pointer must be a bigint/);
+      assert.throws(() => ffi[name](undefined), /The pointer must be a bigint/);
+    }
+  }
+
+  assert.throws(() => ffi.toBuffer(1n), /The length must be a number/);
+  assert.throws(() => ffi.toBuffer(1n, undefined), /The length must be a number/);
+  assert.throws(() => ffi.toArrayBuffer(1n), /The length must be a number/);
+  assert.throws(() => ffi.toArrayBuffer(1n, undefined), /The length must be a number/);
+});