all: Use MP_REGISTER_EXTENSIBLE_MODULE for overrideable built-ins.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

extmod/modbinascii.c

@@ -203,6 +203,6 @@ const mp_obj_module_t mp_module_binascii = {
     .globals = (mp_obj_dict_t *)&mp_module_binascii_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_binascii, mp_module_binascii);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_binascii, mp_module_binascii);
 
 #endif // MICROPY_PY_BINASCII

extmod/modbluetooth.c

@@ -1004,7 +1004,11 @@ const mp_obj_module_t mp_module_bluetooth = {
     .globals = (mp_obj_dict_t *)&mp_module_bluetooth_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_bluetooth, mp_module_bluetooth);
+// This module should not be extensible (as it is not a CPython standard
+// library nor is it necessary to override from the filesystem), however it
+// has previously been known as `ubluetooth`, so by making it extensible the
+// `ubluetooth` alias will continue to work.
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_bluetooth, mp_module_bluetooth);
 
 // Helpers
 

extmod/modcryptolib.c

@@ -375,6 +375,10 @@ const mp_obj_module_t mp_module_cryptolib = {
     .globals = (mp_obj_dict_t *)&mp_module_cryptolib_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_cryptolib, mp_module_cryptolib);
+// This module should not be extensible (as it is not a CPython standard
+// library nor is it necessary to override from the filesystem), however it
+// has previously been known as `ucryptolib`, so by making it extensible the
+// `ucryptolib` alias will continue to work.
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_cryptolib, mp_module_cryptolib);
 
 #endif // MICROPY_PY_CRYPTOLIB

extmod/modhashlib.c

@@ -374,6 +374,6 @@ const mp_obj_module_t mp_module_hashlib = {
     .globals = (mp_obj_dict_t *)&mp_module_hashlib_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_hashlib, mp_module_hashlib);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_hashlib, mp_module_hashlib);
 
 #endif // MICROPY_PY_HASHLIB

extmod/modheapq.c

@@ -118,7 +118,7 @@ const mp_obj_module_t mp_module_heapq = {
     .globals = (mp_obj_dict_t *)&mp_module_heapq_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_heapq, mp_module_heapq);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_heapq, mp_module_heapq);
 #endif
 
 #endif // MICROPY_PY_HEAPQ

extmod/modjson.c

@@ -381,6 +381,6 @@ const mp_obj_module_t mp_module_json = {
     .globals = (mp_obj_dict_t *)&mp_module_json_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_json, mp_module_json);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_json, mp_module_json);
 
 #endif // MICROPY_PY_JSON

extmod/modlwip.c

@@ -1802,7 +1802,7 @@ const mp_obj_module_t mp_module_lwip = {
 MP_REGISTER_MODULE(MP_QSTR_lwip, mp_module_lwip);
 
 // On LWIP-ports, this is the socket module (replaces extmod/modsocket.c).
-MP_REGISTER_MODULE(MP_QSTR_socket, mp_module_lwip);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_socket, mp_module_lwip);
 
 MP_REGISTER_ROOT_POINTER(mp_obj_t lwip_slip_stream);
 

extmod/modos.c

@@ -195,6 +195,6 @@ const mp_obj_module_t mp_module_os = {
     .globals = (mp_obj_dict_t *)&os_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_os, mp_module_os);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_os, mp_module_os);
 
 #endif // MICROPY_PY_OS

extmod/modplatform.c

@@ -75,6 +75,6 @@ const mp_obj_module_t mp_module_platform = {
     .globals = (mp_obj_dict_t *)&modplatform_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_platform, mp_module_platform);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_platform, mp_module_platform);
 
 #endif // MICROPY_PY_PLATFORM

extmod/modrandom.c

@@ -255,7 +255,7 @@ const mp_obj_module_t mp_module_random = {
     .globals = (mp_obj_dict_t *)&mp_module_random_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_random, mp_module_random);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_random, mp_module_random);
 #endif
 
 #endif // MICROPY_PY_RANDOM

extmod/modre.c

@@ -470,7 +470,7 @@ const mp_obj_module_t mp_module_re = {
     .globals = (mp_obj_dict_t *)&mp_module_re_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_re, mp_module_re);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_re, mp_module_re);
 #endif
 
 // Source files #include'd here to make sure they're compiled in

extmod/modselect.c

@@ -373,6 +373,6 @@ const mp_obj_module_t mp_module_select = {
     .globals = (mp_obj_dict_t *)&mp_module_select_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_select, mp_module_select);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_select, mp_module_select);
 
 #endif // MICROPY_PY_SELECT

extmod/modsocket.c

@@ -653,6 +653,6 @@ const mp_obj_module_t mp_module_socket = {
     .globals = (mp_obj_dict_t *)&mp_module_socket_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_socket, mp_module_socket);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_socket, mp_module_socket);
 
 #endif // MICROPY_PY_NETWORK && MICROPY_PY_SOCKET && !MICROPY_PY_LWIP

extmod/modssl_axtls.c

@@ -357,6 +357,6 @@ const mp_obj_module_t mp_module_ssl = {
     .globals = (mp_obj_dict_t *)&mp_module_ssl_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_ssl, mp_module_ssl);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_ssl, mp_module_ssl);
 
 #endif // MICROPY_PY_SSL && MICROPY_SSL_AXTLS

extmod/modssl_mbedtls.c

@@ -507,6 +507,6 @@ const mp_obj_module_t mp_module_ssl = {
     .globals = (mp_obj_dict_t *)&mp_module_ssl_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_ssl, mp_module_ssl);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_ssl, mp_module_ssl);
 
 #endif // MICROPY_PY_SSL && MICROPY_SSL_MBEDTLS

extmod/modtime.c

@@ -231,6 +231,6 @@ const mp_obj_module_t mp_module_time = {
     .globals = (mp_obj_dict_t *)&mp_module_time_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_time, mp_module_time);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_time, mp_module_time);
 
 #endif // MICROPY_PY_TIME

extmod/modtimeq.c

@@ -230,6 +230,6 @@ const mp_obj_module_t mp_module_timeq = {
     .globals = (mp_obj_dict_t *)&mp_module_timeq_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_timeq, mp_module_timeq);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_timeq, mp_module_timeq);
 
 #endif // MICROPY_PY_TIMEQ

extmod/moductypes.c

@@ -718,6 +718,8 @@ const mp_obj_module_t mp_module_uctypes = {
     .globals = (mp_obj_dict_t *)&mp_module_uctypes_globals,
 };
 
+// uctypes is not a Python standard library module (hence "uctypes"
+// not "ctypes") and therefore shouldn't be extensible.
 MP_REGISTER_MODULE(MP_QSTR_uctypes, mp_module_uctypes);
 
 #endif

extmod/modwebsocket.c

@@ -311,6 +311,10 @@ const mp_obj_module_t mp_module_websocket = {
     .globals = (mp_obj_dict_t *)&websocket_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_websocket, mp_module_websocket);
+// This module should not be extensible (as it is not a CPython standard
+// library nor is it necessary to override from the filesystem), however it
+// has previously been known as `uwebsocket`, so by making it extensible the
+// `uwebsocket` alias will continue to work.
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_websocket, mp_module_websocket);
 
 #endif // MICROPY_PY_WEBSOCKET

extmod/modzlib.c

@@ -224,7 +224,7 @@ const mp_obj_module_t mp_module_zlib = {
 };
 
 
-MP_REGISTER_MODULE(MP_QSTR_zlib, mp_module_zlib);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_zlib, mp_module_zlib);
 #endif
 
 // Source files #include'd here to make sure they're compiled in

ports/cc3200/mods/modmachine.c

@@ -214,5 +214,5 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t*)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 MP_REGISTER_ROOT_POINTER(mp_obj_t machine_config_main);

ports/cc3200/mods/modos.c

@@ -180,4 +180,4 @@ const mp_obj_module_t mp_module_os = {
     .globals = (mp_obj_dict_t*)&os_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_os, mp_module_os);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_os, mp_module_os);

ports/cc3200/mods/modsocket.c

@@ -818,4 +818,4 @@ const mp_obj_module_t mp_module_socket = {
     .globals = (mp_obj_dict_t*)&mp_module_socket_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_socket, mp_module_socket);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_socket, mp_module_socket);

ports/cc3200/mods/modssl.c

@@ -160,4 +160,4 @@ const mp_obj_module_t mp_module_ssl = {
     .globals = (mp_obj_dict_t*)&mp_module_ssl_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_ssl, mp_module_ssl);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_ssl, mp_module_ssl);

ports/esp32/modmachine.c

@@ -353,6 +353,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/esp32/modsocket.c

@@ -872,4 +872,4 @@ const mp_obj_module_t mp_module_socket = {
 // Note: This port doesn't define MICROPY_PY_SOCKET or MICROPY_PY_LWIP so
 // this will not conflict with the common implementation provided by
 // extmod/mod{lwip,socket}.c.
-MP_REGISTER_MODULE(MP_QSTR_socket, mp_module_socket);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_socket, mp_module_socket);

ports/esp8266/modmachine.c

@@ -456,6 +456,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/mimxrt/modmachine.c

@@ -185,6 +185,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/nrf/modules/machine/modmachine.c

@@ -266,6 +266,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t*)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/nrf/modules/os/modos.c

@@ -197,4 +197,4 @@ const mp_obj_module_t mp_module_os = {
     .globals = (mp_obj_dict_t*)&os_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_os, mp_module_os);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_os, mp_module_os);

ports/qemu-arm/modmachine.c

@@ -48,6 +48,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/renesas-ra/modmachine.c

@@ -307,6 +307,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/rp2/modmachine.c

@@ -278,6 +278,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/samd/modmachine.c

@@ -297,6 +297,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/stm32/modmachine.c

@@ -471,6 +471,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/unix/modmachine.c

@@ -110,6 +110,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/unix/modselect.c

@@ -351,6 +351,6 @@ const mp_obj_module_t mp_module_select = {
     .globals = (mp_obj_dict_t *)&mp_module_select_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_select, mp_module_select);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_select, mp_module_select);
 
 #endif // MICROPY_PY_SELECT_POSIX

ports/unix/modsocket.c

@@ -707,6 +707,6 @@ const mp_obj_module_t mp_module_socket = {
     .globals = (mp_obj_dict_t *)&mp_module_socket_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_socket, mp_module_socket);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_socket, mp_module_socket);
 
 #endif // MICROPY_PY_SOCKET

ports/zephyr/modmachine.c

@@ -89,6 +89,6 @@ const mp_obj_module_t mp_module_machine = {
     .globals = (mp_obj_dict_t *)&machine_module_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_machine, mp_module_machine);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_machine, mp_module_machine);
 
 #endif // MICROPY_PY_MACHINE

ports/zephyr/modsocket.c

@@ -473,6 +473,6 @@ const mp_obj_module_t mp_module_socket = {
     .globals = (mp_obj_dict_t *)&mp_module_socket_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_socket, mp_module_socket);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_socket, mp_module_socket);
 
 #endif // MICROPY_PY_SOCKET

py/builtinimport.c

@@ -380,20 +380,23 @@ STATIC mp_obj_t process_import_at_level(qstr full_mod_name, qstr level_mod_name,
     mp_obj_t module_obj;
 
     if (outer_module_obj == MP_OBJ_NULL) {
+        // First module in the dotted-name path.
         DEBUG_printf("Searching for top-level module\n");
 
         // An import of a non-extensible built-in will always bypass the
-        // filesystem. e.g. `import micropython` or `import pyb`.
+        // filesystem. e.g. `import micropython` or `import pyb`. So try and
+        // match a non-extensible built-ins first.
         module_obj = mp_module_get_builtin(level_mod_name, false);
         if (module_obj != MP_OBJ_NULL) {
             return module_obj;
         }
 
-        // First module in the dotted-name; search for a directory or file
-        // relative to all the locations in sys.path.
+        // Next try the filesystem. Search for a directory or file relative to
+        // all the locations in sys.path.
         stat = stat_top_level(level_mod_name, &path);
 
-        // TODO: If stat failed, now try extensible built-in modules.
+        // If filesystem failed, now try and see if it matches an extensible
+        // built-in module.
         if (stat == MP_IMPORT_STAT_NO_EXIST) {
             module_obj = mp_module_get_builtin(level_mod_name, true);
             if (module_obj != MP_OBJ_NULL) {

py/modarray.c

@@ -40,6 +40,6 @@ const mp_obj_module_t mp_module_array = {
     .globals = (mp_obj_dict_t *)&mp_module_array_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_array, mp_module_array);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_array, mp_module_array);
 
 #endif

py/modcollections.c

@@ -46,6 +46,6 @@ const mp_obj_module_t mp_module_collections = {
     .globals = (mp_obj_dict_t *)&mp_module_collections_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_collections, mp_module_collections);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_collections, mp_module_collections);
 
 #endif // MICROPY_PY_COLLECTIONS

py/moderrno.c

@@ -99,7 +99,7 @@ const mp_obj_module_t mp_module_errno = {
     .globals = (mp_obj_dict_t *)&mp_module_errno_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_errno, mp_module_errno);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_errno, mp_module_errno);
 
 qstr mp_errno_to_str(mp_obj_t errno_val) {
     #if MICROPY_PY_ERRNO_ERRORCODE

py/modio.c

@@ -226,6 +226,6 @@ const mp_obj_module_t mp_module_io = {
     .globals = (mp_obj_dict_t *)&mp_module_io_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_io, mp_module_io);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_io, mp_module_io);
 
 #endif

py/modstruct.c

@@ -266,6 +266,6 @@ const mp_obj_module_t mp_module_struct = {
     .globals = (mp_obj_dict_t *)&mp_module_struct_globals,
 };
 
-MP_REGISTER_MODULE(MP_QSTR_struct, mp_module_struct);
+MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_struct, mp_module_struct);
 
 #endif

py/modsys.c

@@ -294,6 +294,9 @@ const mp_obj_module_t mp_module_sys = {
     .globals = (mp_obj_dict_t *)&mp_module_sys_globals,
 };
 
+// Unlike the other CPython-compatible modules, sys is not extensible from the
+// filesystem. We rely on it to work so that things like sys.path are always
+// available.
 MP_REGISTER_MODULE(MP_QSTR_sys, mp_module_sys);
 
 // If MICROPY_PY_SYS_PATH_ARGV_DEFAULTS is not enabled then these two lists