From 784909ce1655bf8b2a97ac81a3842e844992082f Mon Sep 17 00:00:00 2001
From: Paul Sokolovsky
Date: Wed, 30 Aug 2017 01:35:48 +0300
Subject: py/objtype: Handle NotImplemented return from binary special methods.

NotImplemented means "try other fallbacks (like calling __rop__
instead of __op__) and if nothing works, raise TypeError". As
MicroPython doesn't implement any fallbacks, signal to raise
TypeError right away.
---
 py/obj.h     |  1 +
 py/objtype.c | 18 ++++++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

(limited to 'py')

diff --git a/py/obj.h b/py/obj.h
index 2adcab1a6..323423b3e 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -616,6 +616,7 @@ extern const mp_obj_type_t mp_type_ZeroDivisionError;
 #define mp_const_true (MP_OBJ_FROM_PTR(&mp_const_true_obj))
 #define mp_const_empty_bytes (MP_OBJ_FROM_PTR(&mp_const_empty_bytes_obj))
 #define mp_const_empty_tuple (MP_OBJ_FROM_PTR(&mp_const_empty_tuple_obj))
+#define mp_const_notimplemented (MP_OBJ_FROM_PTR(&mp_const_notimplemented_obj))
 extern const struct _mp_obj_none_t mp_const_none_obj;
 extern const struct _mp_obj_bool_t mp_const_false_obj;
 extern const struct _mp_obj_bool_t mp_const_true_obj;
diff --git a/py/objtype.c b/py/objtype.c
index 08e276d72..4973236a4 100644
--- a/py/objtype.c
+++ b/py/objtype.c
@@ -471,14 +471,28 @@ STATIC mp_obj_t instance_binary_op(mp_binary_op_t op, mp_obj_t lhs_in, mp_obj_t
         .is_type = false,
     };
     mp_obj_class_lookup(&lookup, lhs->base.type);
+
+    mp_obj_t res;
     if (dest[0] == MP_OBJ_SENTINEL) {
-        return mp_binary_op(op, lhs->subobj[0], rhs_in);
+        res = mp_binary_op(op, lhs->subobj[0], rhs_in);
     } else if (dest[0] != MP_OBJ_NULL) {
         dest[2] = rhs_in;
-        return mp_call_method_n_kw(1, 0, dest);
+        res = mp_call_method_n_kw(1, 0, dest);
     } else {
         return MP_OBJ_NULL; // op not supported
     }
+
+    #if MICROPY_PY_BUILTINS_NOTIMPLEMENTED
+    // NotImplemented means "try other fallbacks (like calling __rop__
+    // instead of __op__) and if nothing works, raise TypeError". As
+    // MicroPython doesn't implement any fallbacks, signal to raise
+    // TypeError right away.
+    if (res == mp_const_notimplemented) {
+        return MP_OBJ_NULL; // op not supported
+    }
+    #endif
+
+    return res;
 }
 
 STATIC void mp_obj_instance_load_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
-- 
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