buffer: allow .write() offset to be at buffer end

Do not throw if the offset passed to `buf.write()` points to the end of the buffer. Fixes: nodejs#8127
addaleax · Aug 18, 2016 · d36adb2 · d36adb2
1 parent 24e4488
commit d36adb2
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Showing 2 changed files with 4 additions and 1 deletion.
diff --git a/src/node_buffer.cc b/src/node_buffer.cc
@@ -714,7 +714,7 @@ void StringWrite(const FunctionCallbackInfo<Value>& args) {
   size_t max_length;
 
   CHECK_NOT_OOB(ParseArrayIndex(args[1], 0, &offset));
-  if (offset >= ts_obj_length)
+  if (offset > ts_obj_length)
     return env->ThrowRangeError("Offset is out of bounds");
 
   CHECK_NOT_OOB(ParseArrayIndex(args[2], ts_obj_length - offset, &max_length));

diff --git a/test/parallel/test-buffer-alloc.js b/test/parallel/test-buffer-alloc.js
@@ -358,6 +358,9 @@ writeTest.write('e', 3, 'ascii');
 writeTest.write('j', 4, 'ascii');
 assert.equal(writeTest.toString(), 'nodejs');
 
+// Does not throw (see https://github.com/nodejs/node/issues/8127).
+Buffer.alloc(1).write('', 1, 0);
+
 // ASCII slice test
 {
   const asciiString = 'hello world';