esp32: socket.bind() fails with a strange error.

[robert-hh]

Firmware version:
MicroPython v1.19.1-443-g30e50ab19 on 2022-09-25; ESP32 module with ESP32 or
MicroPython v1.19.1-443-g30e50ab19 on 2022-09-25; ESP32 module (spiram) with ESP32
esp-idf version 4.4

This little script:

import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('0.0.0.0', 12345))

Causes the error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "bindfail.py", line 4, in <module>
TypeError: can't convert 'int' object to str implicitly

But only if it is executed as frozen bytecode. Importing it as .py or .mpy file from the file system succeeds. Changing the last line to:

s.bind(('0.0.0.0', int(12345)))

or using a symbol (but not a const) for the port number works as well.

Thanks to @uraich for pointing at that error.

[dpgeorge]

Thanks for the report.

When frozen, that tuple used as the argument to bind turns in to:

static const mp_obj_int_t const_obj__boot_0_1 = {{&mp_type_int}, {.neg=0, .fixed_dig=1, .alloc=1, .len=1, .dig=(uint16_t*)(const uint16_t[]){0x3039}}};
static const mp_rom_obj_tuple_t const_obj__boot_0 = {{&mp_type_tuple}, 2, {
    MP_ROM_QSTR(MP_QSTR_0_dot_0_dot_0_dot_0),
    MP_ROM_PTR(&const_obj__boot_0_1),
}};

You can see that the port number is encoded as a big int.

The code for bind that extracts the port number assumes it's a small int:

static int _socket_getaddrinfo2(const mp_obj_t host, const mp_obj_t portx, struct addrinfo **resp) {
    const struct addrinfo hints = {
        .ai_family = AF_INET,
        .ai_socktype = SOCK_STREAM,
    };

    mp_obj_t port = portx;
    if (mp_obj_is_small_int(port)) {
        ...

So the fix is to change that mp_obj_is_small_int() to mp_obj_is_integer().

Also, it should probable be frozen as a small int, so that would be a good thing to improve as well.

[robert-hh]

Thank you for the swift reply. It's always impressive to see how you know every little detail and dependency of MicroPython.
The change from mp_obj_is_small_int() to mp_obj_is_integer() works. I can make a PR for that, if you like.
Changing the frozen bytecode content however is definitely beyond my experience.

[dpgeorge]

Thanks for confirming. I will fix it.

[uraich]

All I can say: I am impressed!
Many thanks to both of you.

[dpgeorge]

Fixed by 3abcfb9