py: Change MP_UNARY_OP_INT to MP_UNARY_OP_INT_MAYBE.

To be consistent with MP_UNARY_OP_INT_FLOAT and MP_UNARY_OP_INT_COMPLEX,
and allow int() to first check if a type supports __int__ before trying
other things (as per CPython).

Signed-off-by: Damien George <damien@micropython.org>

extmod/moductypes.c

@@ -582,7 +582,7 @@ STATIC mp_obj_t uctypes_struct_subscr(mp_obj_t self_in, mp_obj_t index_in, mp_ob
 STATIC mp_obj_t uctypes_struct_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
     mp_obj_uctypes_struct_t *self = MP_OBJ_TO_PTR(self_in);
     switch (op) {
-        case MP_UNARY_OP_INT:
+        case MP_UNARY_OP_INT_MAYBE:
             if (mp_obj_is_type(self->desc, &mp_type_tuple)) {
                 mp_obj_tuple_t *t = MP_OBJ_TO_PTR(self->desc);
                 mp_int_t offset = MP_OBJ_SMALL_INT_VALUE(t->items[0]);

py/obj.c

@@ -298,18 +298,11 @@ mp_int_t mp_obj_get_int(mp_const_obj_t arg) {
     // This function essentially performs implicit type conversion to int
     // Note that Python does NOT provide implicit type conversion from
     // float to int in the core expression language, try some_list[1.0].
-    if (arg == mp_const_false) {
-        return 0;
-    } else if (arg == mp_const_true) {
-        return 1;
-    } else if (mp_obj_is_small_int(arg)) {
-        return MP_OBJ_SMALL_INT_VALUE(arg);
-    } else if (mp_obj_is_exact_type(arg, &mp_type_int)) {
-        return mp_obj_int_get_checked(arg);
-    } else {
-        mp_obj_t res = mp_unary_op(MP_UNARY_OP_INT, (mp_obj_t)arg);
-        return mp_obj_int_get_checked(res);
+    mp_int_t val;
+    if (!mp_obj_get_int_maybe(arg, &val)) {
+        mp_raise_TypeError_int_conversion(arg);
     }
+    return val;
 }
 
 mp_int_t mp_obj_get_int_truncated(mp_const_obj_t arg) {

py/objint.c

@@ -48,10 +48,10 @@ STATIC mp_obj_t mp_obj_int_make_new(const mp_obj_type_t *type_in, size_t n_args,
         case 0:
             return MP_OBJ_NEW_SMALL_INT(0);
 
-        case 1:
-            if (mp_obj_is_int(args[0])) {
-                // already an int (small or long), just return it
-                return args[0];
+        case 1: {
+            mp_obj_t o = mp_unary_op(MP_UNARY_OP_INT_MAYBE, args[0]);
+            if (o != MP_OBJ_NULL) {
+                return o;
             } else if (mp_obj_is_str_or_bytes(args[0])) {
                 // a string, parse it
                 size_t l;
@@ -62,7 +62,8 @@ STATIC mp_obj_t mp_obj_int_make_new(const mp_obj_type_t *type_in, size_t n_args,
                 return mp_obj_new_int_from_float(mp_obj_float_get(args[0]));
             #endif
             } else {
-                return mp_unary_op(MP_UNARY_OP_INT, args[0]);
+                mp_raise_TypeError_int_conversion(args[0]);
+            }
         }
 
         case 2:

py/objint_longlong.c

@@ -119,6 +119,8 @@ mp_obj_t mp_obj_int_unary_op(mp_unary_op_t op, mp_obj_t o_in) {
             self->val = -self->val;
             return MP_OBJ_FROM_PTR(self);
         }
+        case MP_UNARY_OP_INT_MAYBE:
+            return o_in;
         default:
             return MP_OBJ_NULL;      // op not supported
     }

py/objint_mpz.c

@@ -165,6 +165,8 @@ mp_obj_t mp_obj_int_unary_op(mp_unary_op_t op, mp_obj_t o_in) {
             mpz_abs_inpl(&self2->mpz, &self->mpz);
             return MP_OBJ_FROM_PTR(self2);
         }
+        case MP_UNARY_OP_INT_MAYBE:
+            return o_in;
         default:
             return MP_OBJ_NULL;      // op not supported
     }

py/objtype.c

@@ -374,7 +374,7 @@ const byte mp_unary_op_method_name[MP_UNARY_OP_NUM_RUNTIME] = {
     [MP_UNARY_OP_BOOL] = MP_QSTR___bool__,
     [MP_UNARY_OP_LEN] = MP_QSTR___len__,
     [MP_UNARY_OP_HASH] = MP_QSTR___hash__,
-    [MP_UNARY_OP_INT] = MP_QSTR___int__,
+    [MP_UNARY_OP_INT_MAYBE] = MP_QSTR___int__,
     #if MICROPY_PY_ALL_SPECIAL_METHODS
     [MP_UNARY_OP_POSITIVE] = MP_QSTR___pos__,
     [MP_UNARY_OP_NEGATIVE] = MP_QSTR___neg__,
@@ -432,7 +432,7 @@ STATIC mp_obj_t instance_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
                 // __hash__ must return a small int
                 val = MP_OBJ_NEW_SMALL_INT(mp_obj_get_int_truncated(val));
                 break;
-            case MP_UNARY_OP_INT:
+            case MP_UNARY_OP_INT_MAYBE:
                 // Must return int
                 if (!mp_obj_is_int(val)) {
                     mp_raise_TypeError(NULL);

py/runtime.c

@@ -277,7 +277,7 @@ mp_obj_t mp_unary_op(mp_unary_op_t op, mp_obj_t arg) {
             case MP_UNARY_OP_HASH:
                 return arg;
             case MP_UNARY_OP_POSITIVE:
-            case MP_UNARY_OP_INT:
+            case MP_UNARY_OP_INT_MAYBE:
                 return arg;
             case MP_UNARY_OP_NEGATIVE:
                 // check for overflow
@@ -324,32 +324,23 @@ mp_obj_t mp_unary_op(mp_unary_op_t op, mp_obj_t arg) {
             // if arg==mp_const_none.
             return mp_const_true;
         }
+        if (op == MP_UNARY_OP_INT_MAYBE
             #if MICROPY_PY_BUILTINS_FLOAT
-        if (op == MP_UNARY_OP_FLOAT_MAYBE
+            || op == MP_UNARY_OP_FLOAT_MAYBE
             #if MICROPY_PY_BUILTINS_COMPLEX
             || op == MP_UNARY_OP_COMPLEX_MAYBE
             #endif
+            #endif
             ) {
+            // These operators may return MP_OBJ_NULL if they are not supported by the type.
             return MP_OBJ_NULL;
         }
-        #endif
-        // With MP_UNARY_OP_INT, mp_unary_op() becomes a fallback for mp_obj_get_int().
-        // In this case provide a more focused error message to not confuse, e.g. chr(1.0)
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
-        if (op == MP_UNARY_OP_INT) {
-            mp_raise_TypeError(MP_ERROR_TEXT("can't convert to int"));
-        } else {
         mp_raise_TypeError(MP_ERROR_TEXT("unsupported type for operator"));
-        }
         #else
-        if (op == MP_UNARY_OP_INT) {
-            mp_raise_msg_varg(&mp_type_TypeError,
-                MP_ERROR_TEXT("can't convert %s to int"), mp_obj_get_type_str(arg));
-        } else {
         mp_raise_msg_varg(&mp_type_TypeError,
             MP_ERROR_TEXT("unsupported type for %q: '%s'"),
             mp_unary_op_method_name[op], mp_obj_get_type_str(arg));
-        }
         #endif
     }
 }
@@ -1700,6 +1691,16 @@ NORETURN void mp_raise_StopIteration(mp_obj_t arg) {
     }
 }
 
+NORETURN void mp_raise_TypeError_int_conversion(mp_const_obj_t arg) {
+    #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
+    (void)arg;
+    mp_raise_TypeError(MP_ERROR_TEXT("can't convert to int"));
+    #else
+    mp_raise_msg_varg(&mp_type_TypeError,
+        MP_ERROR_TEXT("can't convert %s to int"), mp_obj_get_type_str(arg));
+    #endif
+}
+
 NORETURN void mp_raise_OSError(int errno_) {
     mp_raise_type_arg(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT(errno_));
 }

py/runtime.h

@@ -198,6 +198,7 @@ NORETURN void mp_raise_NotImplementedError(mp_rom_error_text_t msg);
 
 NORETURN void mp_raise_type_arg(const mp_obj_type_t *exc_type, mp_obj_t arg);
 NORETURN void mp_raise_StopIteration(mp_obj_t arg);
+NORETURN void mp_raise_TypeError_int_conversion(mp_const_obj_t arg);
 NORETURN void mp_raise_OSError(int errno_);
 NORETURN void mp_raise_OSError_with_filename(int errno_, const char *filename);
 NORETURN void mp_raise_recursion_depth(void);

py/runtime0.h

@@ -75,7 +75,7 @@ typedef enum {
     MP_UNARY_OP_LEN, // __len__
     MP_UNARY_OP_HASH, // __hash__; must return a small int
     MP_UNARY_OP_ABS, // __abs__
-    MP_UNARY_OP_INT, // __int__
+    MP_UNARY_OP_INT_MAYBE, // __int__; must return MP_OBJ_NULL, or an object satisfying mp_obj_is_int()
     MP_UNARY_OP_FLOAT_MAYBE, // __float__
     MP_UNARY_OP_COMPLEX_MAYBE, // __complex__
     MP_UNARY_OP_SIZEOF, // for sys.getsizeof()

tests/basics/int_big1.py

@@ -10,6 +10,9 @@ print(y)
 print('%#X' % (x - x)) # print prefix
 print('{:#,}'.format(x)) # print with commas
 
+# construction
+print(int(x))
+
 # addition
 print(x + 1)
 print(x + y)

tests/basics/special_methods_intbig.py

@@ -0,0 +1,8 @@
+# Test class special methods, that use a bigint.
+
+class A:
+    def __int__(self):
+        return 1 << 100
+
+
+print(int(A()))