fix split with empty bytes

Author: jgirardet

tests/snippets/bytes.py

@@ -355,6 +355,10 @@
 assert b"1 2 3".split(maxsplit=1) == [b"1", b"2 3"]
 assert b"   1   2   3   ".split() == [b"1", b"2", b"3"]
 assert b"k\ruh\nfz e f".split() == [b"k", b"uh", b"fz", b"e", b"f"]
+assert b"Two lines\n".split(b'\n') == [b'Two lines', b'']
+assert b"".split() == []
+assert b"".split(b"\n") == [b'']
+assert b"\n".split(b"\n") == [b'', b'']
 
 SPLIT_FIXTURES = [
     [

vm/src/obj/objbyteinner.rs

@@ -837,6 +837,13 @@ impl PyByteInner {
     ) -> PyResult<Vec<&[u8]>> {
         let (sep, maxsplit) = options.get_value(vm)?;
 
+        if self.elements.is_empty() {
+            if !sep.is_empty() {
+                return Ok(vec![&[]]);
+            }
+            return Ok(vec![]);
+        }
+
         if reverse {
             Ok(split_slice_reverse(&self.elements, &sep, maxsplit))
         } else {