py/objint_longlong: Fix overflow check in mp_obj_int_get_checked.

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 <dev@yoctopuce.com>

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) {

tests/basics/int_64_basics.py

@@ -125,6 +125,22 @@ else:
 x = 1 << 62
 print('a' * (x + 4 - x))
 
+# test overflow check in mp_obj_get_int_maybe
+x = 1 << 32
+r = None
+try:
+    r = range(0, x)
+except OverflowError:
+    # 32-bit target, correctly handled the overflow of x
+    print("ok")
+if r is not None:
+    if len(r) == x:
+        # 64-bit target, everything is just a small-int
+        print("ok")
+    else:
+        # 32-bit target that did not handle the overflow of x
+        print("unhandled overflow")
+
 # negative shifts are invalid
 try:
     print((1 << 48) >> -4)