Fix bytearray iteration in 0.29.x (#4108)

By explicitly setting the result type

Cython/Compiler/ExprNodes.py

@@ -2876,6 +2876,10 @@ class NextNode(AtomicExprNode):
             iterator_type = self.iterator.infer_type(env)
         if iterator_type.is_ptr or iterator_type.is_array:
             return iterator_type.base_type
+        elif self.iterator.sequence.type is bytearray_type:
+            # This is a temporary work-around to fix bytearray iteration in 0.29.x
+            # It has been fixed properly in master, refer to ticket: 3473
+            return py_object_type
         elif iterator_type.is_cpp_class:
             item_type = env.lookup_operator_for_types(self.pos, "*", [iterator_type]).type.return_type
             if item_type.is_reference:

tests/run/bytearray_iter.py

+# mode: run
+# ticket: 3473
+
+def test_bytearray_iteration(src):
+    """
+    >>> src = b'123'
+    >>> test_bytearray_iteration(src)
+    49
+    50
+    51
+    """
+
+    data = bytearray(src)
+    for elem in data:
+        print(elem)