AVR + Debug mode = Assert failed

Created by: labodj

Hi, I think I have found a bug in 6.15 version, the problem doesn't occur in 6.14.1, i'm compiling with GCC 9.2.0 (https://blog.zakkemble.net/avr-gcc-builds/) using platformio and VSCode under linux 64bit for Controllino Maxi (ATmega2560).

I have this method that prepares a json to be sent:

void Serializer::serializeNetworkClick(uint8_t buttonIndex, constants::ButtonClickType clickType, bool confirm) const
{
    using namespace constants;
    StaticJsonDocument<JSON_OBJECT_SIZE(4)> doc;

    // Write the Json
    doc[JSON_PAYLOAD] = serialized(JSON_PAYLOAD_COMMAND_NETWORK_CLICK_SERIALIZED);

    switch (clickType)
    {
    case ButtonClickType::LONG:
        doc[JSON_DATA_CLICK_TYPE] = serialized(JSON_DATA_CLICK_TYPE_LONG_SERIALIZED);
        break;
    case ButtonClickType::SUPER_LONG:
        doc[JSON_DATA_CLICK_TYPE] = serialized(JSON_DATA_CLICK_TYPE_SUPER_LONG_SERIALIZED);
        break;
    default:
        return;
    }

    doc[JSON_DATA_BUTTONS_IDS] = this->device.getButton(buttonIndex)->getId();
    doc[JSON_DATA_CONFIRM] = confirm;

    // Send the Json
    this->com->sendJson(doc);
}

Useful related code: Merged from various constants .hpp files

namespace constants
{
static constexpr const char *JSON_PAYLOAD = "p";
static constexpr const char *JSON_DATA_CLICK_TYPE = "ct";
static constexpr const char *JSON_DATA_BUTTONS_IDS = "bi";
static constexpr const char *JSON_DATA_CONFIRM = "c";

static constexpr const char *JSON_PAYLOAD_COMMAND_NETWORK_CLICK_SERIALIZED = "\"c_nc\"";
static constexpr const char *JSON_DATA_CLICK_TYPE_LONG_SERIALIZED = "\"lc\"";
static constexpr const char *JSON_DATA_CLICK_TYPE_SUPER_LONG_SERIALIZED = "\"slc\"";

enum class ButtonClickType
{
    NONE,
    SHORT,
    LONG,
    SUPER_LONG
};
} // namespace constants

from device.cpp

Clickable *Device::getButton(uint8_t buttonIndex) const
{
    return this->buttons[buttonIndex]; // this->buttons is a std::vector<Clickable *>
}

from clickable.cpp

const char *Clickable::getId() const
{
    return this->id; // this->id is a const char *const
}

from espcom.cpp

void EspCom::sendJson(const JsonDocument &json)
{
    serializeJson(json, (*this->serial)); // this->serial is a HardwareSerial *const
    DJ(json);
    this->storeSentPayloadTime();
}

from debug.hpp

#define DJ(x)                     \
    do                            \
    {                             \
        serializeJson(x, Serial); \
        Serial.println();         \
    } while (0)

The problem is that when all 4 fields are set the program crashes at runtime. If any of these 4 fields are removed the program runs fine. I tried to use larger StaticJsonDocument without success.

At the moment I'll stay with 6.14.1 until I find a fix or a workaround.

Another unrelated question: is serialized used like the code above actually faster than passing a normal (not preformatted) static constexpr const char *? like

doc[JSON_PAYLOAD] = constants::JSON_PAYLOAD_COMMAND_NETWORK_CLICK;

namespace constants
{
static constexpr const char *JSON_PAYLOAD_COMMAND_NETWORK_CLICK = "c_nc";
} // namespace constants

EDIT: I've just tested it with GCC-9.3.0 (https://blog.zakkemble.net/avr-gcc-builds/comment-page-1/#comment-209216) with Ofast, Os, O1 and O2 optimizations and latest commit on master targeting the library on platformio wih this repo link, same problem.