Bug in 1.1.6 release: using namespace mbed clash on Serial definition

[janjongboom]

@facchinm Since the 1.1.6 release of this Arduino core we have naming issues between the Arduino and the Mbed serial interfaces. Has anything changed here?

Arduino: 1.8.13 (Windows 10), Board: “Arduino Nano 33 BLE”

In file included from sketch\static_buffer.ino.cpp:1:0:

C:\Users\kasim\OneDrive\Documents\Arduino\libraries\ei-plant_pot-arduino-1.0.1\examples\static_buffer\static_buffer.ino: In function ‘void setup()’:

C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/Arduino.h:128:16: error: reference to ‘SerialUSB’ is ambiguous

#define Serial SerialUSB

            ^
C:\Users\kasim\OneDrive\Documents\Arduino\libraries\ei-plant_pot-arduino-1.0.1\examples\static_buffer\static_buffer.ino:53:5: note: in expansion of macro ‘Serial’

 Serial.begin(115200);

 ^
In file included from C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/Arduino.h:127:0,

             from sketch\static_buffer.ino.cpp:1:
C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/USB/PluggableUSBSerial.h:279:27: note: candidates are: arduino::USBSerial SerialUSB

extern arduino::USBSerial SerialUSB;

                       ^~~~~~~~~
In file included from sketch\static_buffer.ino.cpp:1:0:

C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/Arduino.h:128:16: note: class mbed::SerialUSB

#define Serial SerialUSB

            ^
C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/mbed/drivers/Serial.h:56:7: note: in expansion of macro ‘Serial’

class Serial : public SerialBase, public Stream, private NonCopyable {

   ^~~~~~
C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/Arduino.h:128:16: error: reference to ‘SerialUSB’ is ambiguous

#define Serial SerialUSB

            ^
C:\Users\kasim\OneDrive\Documents\Arduino\libraries\ei-plant_pot-arduino-1.0.1\examples\static_buffer\static_buffer.ino:55:5: note: in expansion of macro ‘Serial’

 Serial.println("Edge Impulse Inferencing Demo");

 ^
In file included from C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/Arduino.h:127:0,

             from sketch\static_buffer.ino.cpp:1:
C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/USB/PluggableUSBSerial.h:279:27: note: candidates are: arduino::USBSerial SerialUSB

extern arduino::USBSerial SerialUSB;

                       ^~~~~~~~~
In file included from sketch\static_buffer.ino.cpp:1:0:

C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/Arduino.h:128:16: note: class mbed::SerialUSB

#define Serial SerialUSB

            ^
C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/mbed/drivers/Serial.h:56:7: note: in expansion of macro ‘Serial’

class Serial : public SerialBase, public Stream, private NonCopyable {

   ^~~~~~
C:\Users\kasim\OneDrive\Documents\Arduino\libraries\ei-plant_pot-arduino-1.0.1\examples\static_buffer\static_buffer.ino: In function ‘void ei_printf(const char*, …)’:

C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/Arduino.h:128:16: error: reference to ‘SerialUSB’ is ambiguous

#define Serial SerialUSB

            ^
C:\Users\kasim\OneDrive\Documents\Arduino\libraries\ei-plant_pot-arduino-1.0.1\examples\static_buffer\static_buffer.ino:122:9: note: in expansion of macro ‘Serial’

     Serial.write(print_buf);

     ^
In file included from C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/Arduino.h:127:0,

             from sketch\static_buffer.ino.cpp:1:
C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/USB/PluggableUSBSerial.h:279:27: note: candidates are: arduino::USBSerial SerialUSB

extern arduino::USBSerial SerialUSB;

                       ^~~~~~~~~
In file included from sketch\static_buffer.ino.cpp:1:0:

C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/Arduino.h:128:16: note: class mbed::SerialUSB

#define Serial SerialUSB

            ^
C:\Users\kasim\AppData\Local\Arduino15\packages\arduino\hardware\mbed\1.1.6\cores\arduino/mbed/drivers/Serial.h:56:7: note: in expansion of macro ‘Serial’

class Serial : public SerialBase, public Stream, private NonCopyable {

   ^~~~~~
exit status 1

Error compiling for board Arduino Nano 33 BLE.

This report would have more information with
“Show verbose output during compilation”
option enabled in File -> Preferences.

Reported in https://forum.edgeimpulse.com/t/deployment-building-firmware-for-arduino-nano-error/625/5

Here is an Arduino library that demonstrates the problem: ei-continuous-gestures-demo-arduino-1.0.9.zip, and this is the sketch that fails to compile:

/* Includes ---------------------------------------------------------------- */
#include <continuous_gestures_demo_inference.h>

/**
 * @brief      Arduino setup function
 */
void setup()
{
    // put your setup code here, to run once:
    Serial.begin(115200);

    Serial.println("Edge Impulse Inferencing Demo");
}

/**
 * @brief      Arduino main function
 */
void loop()
{
    ei_printf("Edge Impulse standalone inferencing (Arduino)\n");

    delay(1000);
}

/**
 * @brief      Printf function uses vsnprintf and output using Arduino Serial
 *
 * @param[in]  format     Variable argument list
 */
void ei_printf(const char *format, ...) {
    static char print_buf[1024] = { 0 };

    va_list args;
    va_start(args, format);
    int r = vsnprintf(print_buf, sizeof(print_buf), format, args);
    va_end(args);

    if (r > 0) {
        Serial.write(print_buf);
    }
}

[facchinm]

Hi @janjongboom ,
the issue is namespace and compilation order related.
In order to speedup the build mbed.h is not included anymore by default but through a wrapper that takes care to resolve ambiguities.
In src/edge-impulse-sdk/dsp/numpy_types.h" there's a using namespace mbed; directive that gets applied to all the compilation units.
I understand that specifying the namespace of every Callback call is tedious but since all the library is implemented in header files and they include each other every using namespace ... gets applied to the final compilation unit.

I can provide a patch is needed but I'd avoid changing the core internals (again)

[janjongboom]

@facchinm I can get rid of our using namespace mbed calls, but I bet there are heaps of other libraries that have the same behavior, that will break now in a new minor version of the core.