py/runtime: Allow initialising sys.path/argv with defaults.

If MICROPY_PY_SYS_PATH_ARGV_DEFAULTS is enabled (which it is by default)
then sys.path and sys.argv will be initialised and populated with default
values.  This keeps all bare-metal ports aligned.
Signed-off-by: Damien George <damien@micropython.org>

docs/develop/porting.rst

@@ -53,8 +53,6 @@ The basic MicroPython firmware is implemented in the main port file, e.g ``main.
        mp_stack_ctrl_init();
        gc_init(heap, heap + sizeof(heap));
        mp_init();
-       mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_path), 0);
-       mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_argv), 0);
 
        // Start a normal REPL; will exit when ctrl-D is entered on a blank line.
        pyexec_friendly_repl();

mpy-cross/main.c

@@ -192,8 +192,6 @@ MP_NOINLINE int main_(int argc, char **argv) {
     #ifdef _WIN32
     set_fmode_binary();
     #endif
-    mp_obj_list_init(mp_sys_path, 0);
-    mp_obj_list_init(mp_sys_argv, 0);
 
     #if MICROPY_EMIT_NATIVE
     // Set default emitter options

ports/cc3200/mptask.c

@@ -139,9 +139,6 @@ soft_reset:
 
     // MicroPython init
     mp_init();
-    mp_obj_list_init(mp_sys_path, 0);
-    mp_obj_list_init(mp_sys_argv, 0);
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_)); // current dir (or base dir of the script)
 
     // execute all basic initializations
     mp_irq_init0();

ports/esp32/main.c

@@ -140,13 +140,7 @@ soft_reset:
     mp_stack_set_limit(MP_TASK_STACK_SIZE - MP_TASK_STACK_LIMIT_MARGIN);
     gc_init(mp_task_heap, mp_task_heap + mp_task_heap_size);
     mp_init();
-    mp_obj_list_init(mp_sys_path, 0);
-    #if MICROPY_MODULE_FROZEN
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__dot_frozen));
-    #endif
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_));
     mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__slash_lib));
-    mp_obj_list_init(mp_sys_argv, 0);
     readline_init0();
 
     // initialise peripherals

ports/esp8266/main.c

@@ -52,14 +52,8 @@ STATIC void mp_reset(void) {
     mp_hal_init();
     gc_init(heap, heap + sizeof(heap));
     mp_init();
-    mp_obj_list_init(mp_sys_path, 0);
-    #if MICROPY_MODULE_FROZEN
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__dot_frozen));
-    #endif
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_)); // current dir (or base dir of the script)
     mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__slash_lib));
     mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__slash_));
-    mp_obj_list_init(mp_sys_argv, 0);
     #if MICROPY_EMIT_XTENSA || MICROPY_EMIT_INLINE_XTENSA
     extern void esp_native_code_init(void);
     esp_native_code_init();

ports/javascript/main.c

@@ -91,10 +91,6 @@ void mp_js_init(int heap_size) {
     #endif
 
     mp_init();
-
-    mp_obj_list_init(mp_sys_path, 0);
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_));
-    mp_obj_list_init(mp_sys_argv, 0);
 }
 
 void mp_js_init_repl() {

ports/mimxrt/main.c

@@ -75,12 +75,6 @@ int main(void) {
         gc_init(&_gc_heap_start, &_gc_heap_end);
         mp_init();
 
-        mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_path), 0);
-        #if MICROPY_MODULE_FROZEN
-        mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__dot_frozen));
-        #endif
-        mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_));
-        mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_argv), 0);
         #if MICROPY_PY_NETWORK
         mod_network_init();
         #endif

ports/nrf/main.c

@@ -129,16 +129,8 @@ soft_reset:
     gc_init(&_heap_start, &_heap_end);
 
     mp_init();
-    mp_obj_list_init(mp_sys_path, 0);
-    #if MICROPY_MODULE_FROZEN
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__dot_frozen));
-    #endif
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_)); // current dir (or base dir of the script)
-    mp_obj_list_init(mp_sys_argv, 0);
-
     readline_init0();
 
-
     #if MICROPY_PY_MACHINE_HW_SPI
     spi_init0();
     #endif

ports/rp2/main.c

@@ -100,13 +100,7 @@ int main(int argc, char **argv) {
 
         // Initialise MicroPython runtime.
         mp_init();
-        mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_path), 0);
-        #if MICROPY_MODULE_FROZEN
-        mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__dot_frozen));
-        #endif
-        mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_));
         mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__slash_lib));
-        mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_argv), 0);
 
         // Initialise sub-systems.
         readline_init0();

ports/samd/main.c

@@ -41,9 +41,6 @@ void samd_main(void) {
     for (;;) {
         gc_init(&_sheap, &_eheap);
         mp_init();
-        mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_path), 0);
-        mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_));
-        mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_argv), 0);
 
         // Execute _boot.py to set up the filesystem.
         pyexec_frozen_module("_boot.py");

ports/stm32/main.c

@@ -494,12 +494,6 @@ soft_reset:
 
     // MicroPython init
     mp_init();
-    mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_path), 0);
-    #if MICROPY_MODULE_FROZEN
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__dot_frozen));
-    #endif
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_)); // current dir (or base dir of the script)
-    mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_argv), 0);
 
     // Initialise low-level sub-systems.  Here we need to very basic things like
     // zeroing out memory and resetting any of the sub-systems.  Following this

ports/teensy/main.c

@@ -269,9 +269,6 @@ soft_reset:
 
     // MicroPython init
     mp_init();
-    mp_obj_list_init(mp_sys_path, 0);
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_)); // current dir (or base dir of the script)
-    mp_obj_list_init(mp_sys_argv, 0);
 
     readline_init0();
 

ports/unix/mpconfigport.h

@@ -110,6 +110,7 @@
 #define MICROPY_PY_ARRAY_SLICE_ASSIGN (1)
 #define MICROPY_PY_BUILTINS_SLICE_ATTRS (1)
 #define MICROPY_PY_BUILTINS_SLICE_INDICES (1)
+#define MICROPY_PY_SYS_PATH_ARGV_DEFAULTS (0)
 #define MICROPY_PY_SYS_EXIT         (1)
 #define MICROPY_PY_SYS_ATEXIT       (1)
 #if MICROPY_PY_SYS_SETTRACE

ports/windows/mpconfigport.h

@@ -85,6 +85,7 @@
 #define MICROPY_PY_REVERSE_SPECIAL_METHODS (1)
 #define MICROPY_PY_ARRAY_SLICE_ASSIGN (1)
 #define MICROPY_PY_BUILTINS_SLICE_ATTRS (1)
+#define MICROPY_PY_SYS_PATH_ARGV_DEFAULTS (0)
 #define MICROPY_PY_SYS_EXIT         (1)
 #define MICROPY_PY_SYS_ATEXIT       (1)
 #define MICROPY_PY_SYS_PLATFORM     "win32"

ports/zephyr/main.c

@@ -139,9 +139,6 @@ soft_reset:
     gc_init(heap, heap + sizeof(heap));
     #endif
     mp_init();
-    mp_obj_list_init(mp_sys_path, 0);
-    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_)); // current dir (or base dir of the script)
-    mp_obj_list_init(mp_sys_argv, 0);
 
     #ifdef CONFIG_USB
     usb_enable(NULL);

py/mpconfig.h

@@ -1306,6 +1306,11 @@ typedef double mp_float_t;
 #define MICROPY_PY_SYS (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_CORE_FEATURES)
 #endif
 
+// Whether to initialise "sys.path" and "sys.argv" to their defaults in mp_init()
+#ifndef MICROPY_PY_SYS_PATH_ARGV_DEFAULTS
+#define MICROPY_PY_SYS_PATH_ARGV_DEFAULTS (1)
+#endif
+
 // Whether to provide "sys.maxsize" constant
 #ifndef MICROPY_PY_SYS_MAXSIZE
 #define MICROPY_PY_SYS_MAXSIZE (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)

py/mpstate.h

@@ -153,7 +153,8 @@ typedef struct _mp_state_vm_t {
     // dictionary for the __main__ module
     mp_obj_dict_t dict_main;
 
-    // these two lists must be initialised per port, after the call to mp_init
+    // If MICROPY_PY_SYS_PATH_ARGV_DEFAULTS is not enabled then these two lists
+    // must be initialised after the call to mp_init.
     mp_obj_list_t mp_sys_path_obj;
     mp_obj_list_t mp_sys_argv_obj;
 

py/runtime.c

@@ -122,6 +122,15 @@ void mp_init(void) {
     MP_STATE_VM(vfs_mount_table) = NULL;
     #endif
 
+    #if MICROPY_PY_SYS_PATH_ARGV_DEFAULTS
+    mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_path), 0);
+    #if MICROPY_MODULE_FROZEN
+    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__dot_frozen));
+    #endif
+    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_)); // current dir (or base dir of the script)
+    mp_obj_list_init(MP_OBJ_TO_PTR(mp_sys_argv), 0);
+    #endif
+
     #if MICROPY_PY_SYS_ATEXIT
     MP_STATE_VM(sys_exitfunc) = mp_const_none;
     #endif