py/objint_longlong: Fix overflow check in mp_obj_int_get_checked.

yoctopuce · yoctopuce · commit fc5cbad805d7 · 2025-07-22T08:58:33.000+02:00
This is to fix an outstanding TODO. The test cases is using a
range as this will exist in all builds, but mp_obj_get_int
is used in many different parts of code where an overflow
is more likely to occur.

Signed-off-by: Yoctopuce dev &lt;dev@yoctopuce.com&gt;
diff --git a/py/objint_longlong.c b/py/objint_longlong.c
@@ -308,8 +308,17 @@ mp_int_t mp_obj_int_get_truncated(mp_const_obj_t self_in) {
 }
 
 mp_int_t mp_obj_int_get_checked(mp_const_obj_t self_in) {
-    // TODO: Check overflow
-    return mp_obj_int_get_truncated(self_in);
+    if (mp_obj_is_small_int(self_in)) {
+        return MP_OBJ_SMALL_INT_VALUE(self_in);
+    } else {
+        const mp_obj_int_t *self = self_in;
+        long long value = self->val;
+        mp_int_t truncated = (mp_int_t)value;
+        if ((long long)truncated == value) {
+            return truncated;
+        }
+    }
+    mp_raise_msg(&mp_type_OverflowError, MP_ERROR_TEXT("overflow converting long int to machine word"));
 }
 
 mp_uint_t mp_obj_int_get_uint_checked(mp_const_obj_t self_in) {
diff --git a/tests/basics/int_64_basics.py b/tests/basics/int_64_basics.py
@@ -125,6 +125,17 @@
 x = 1 << 62
 print('a' * (x + 4 - x))
 
+# test overflow check in mp_obj_get_int_maybe
+l = [ 0, 1 ]
+x = 1 << 32
+try:
+    if len(l[x:]) == 0:
+        print('ok')
+    else:
+        print('unhandled overflow')
+except OverflowError as e:
+    print('ok')
+
 # negative shifts are invalid
 try:
     print((1 << 48) >> -4)
