py/objtype: Introduce MICROPY_PY_ALL_INPLACE_SPECIAL_METHODS.

This allows to configure support for inplace special methods separately,
similar to "normal" and reverse special methods. This is useful, because
inplace methods are "the most optional" ones, for example, if inplace
methods aren't defined, the operation will be executed using normal
methods instead.

As a caveat, __iadd__ and __isub__ are implemented even if
MICROPY_PY_ALL_INPLACE_SPECIAL_METHODS isn't defined. This is similar
to the state of affairs before binary operations refactor, and allows
to run existing tests even if MICROPY_PY_ALL_INPLACE_SPECIAL_METHODS
isn't defined.

py/mpconfig.h

@@ -765,16 +765,24 @@ typedef double mp_float_t;
 #define MICROPY_PY_BUILTINS_TIMEOUTERROR (0)
 #endif
 
-// Whether to support complete set of special methods
-// for user classes, or only the most used ones. "Reverse"
-// methods are controlled by MICROPY_PY_REVERSE_SPECIAL_METHODS
-// below.
+// Whether to support complete set of special methods for user
+// classes, or only the most used ones. "Inplace" methods are
+// controlled by MICROPY_PY_ALL_INPLACE_SPECIAL_METHODS below.
+// "Reverse" methods are controlled by
+// MICROPY_PY_REVERSE_SPECIAL_METHODS below.
 #ifndef MICROPY_PY_ALL_SPECIAL_METHODS
 #define MICROPY_PY_ALL_SPECIAL_METHODS (0)
 #endif
 
-// Whether to support reverse arithmetic operarions methods
-// (__radd__, etc.)
+// Whether to support all inplace arithmetic operarion methods
+// (__imul__, etc.)
+#ifndef MICROPY_PY_ALL_INPLACE_SPECIAL_METHODS
+#define MICROPY_PY_ALL_INPLACE_SPECIAL_METHODS (0)
+#endif
+
+// Whether to support reverse arithmetic operarion methods
+// (__radd__, etc.). Additionally gated by
+// MICROPY_PY_ALL_SPECIAL_METHODS.
 #ifndef MICROPY_PY_REVERSE_SPECIAL_METHODS
 #define MICROPY_PY_REVERSE_SPECIAL_METHODS (0)
 #endif

py/objtype.c

@@ -422,11 +422,11 @@ const byte mp_binary_op_method_name[MP_BINARY_OP_NUM_RUNTIME] = {
     // MP_BINARY_OP_NOT_EQUAL, // a != b calls a == b and inverts result
     [MP_BINARY_OP_IN] = MP_QSTR___contains__,
 
-    #if MICROPY_PY_ALL_SPECIAL_METHODS
     // All inplace methods are optional, and normal methods will be used
     // as a fallback.
     [MP_BINARY_OP_INPLACE_ADD] = MP_QSTR___iadd__,
     [MP_BINARY_OP_INPLACE_SUBTRACT] = MP_QSTR___isub__,
+    #if MICROPY_PY_ALL_INPLACE_SPECIAL_METHODS
     [MP_BINARY_OP_INPLACE_MULTIPLY] = MP_QSTR___imul__,
     [MP_BINARY_OP_INPLACE_FLOOR_DIVIDE] = MP_QSTR___ifloordiv__,
     [MP_BINARY_OP_INPLACE_TRUE_DIVIDE] = MP_QSTR___itruediv__,