Compiler extra_flags parameter issue

[pstolarz]

Board

any

Device Description

n/a

Hardware Configuration

n/a

Version

latest master (checkout manually)

IDE Name

arduino-cli

Operating System

Linux

Flash frequency

n/a

PSRAM enabled

yes

Upload speed

n/a

Description

Current version of the platform.txt file contains new versions of compiler.c.extra_flags, compiler.cpp.extra_flags and compiler.S.extra_flags parameters which are not empty (the change provided by 6f7a1ca). I've been using these parameters to pass extra flags for the C/C++ compiler for the arduino-cli tool. Currently I'm not able to do this, since my passed flags interfere with the flags in platform.txt causing compilation error.

Could you consider moving these flags from compiler.XXX.extra_flags to compiler.XXX.flags and leave the extra flags empty for exclusive user usage as it is for other Arduino cores?

Sketch

n/a

Debug Message

| /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/xtensa-esp32-elf-g++ -DCONFIG_PWR_CTRL_ENABLED -DCONFIG_OVERDRIVE_ENABLED -DCONFIG_CRC16_ENABLED -DCONFIG_ITERATION_RETRIES=1 @/root/.arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.1-6b1f40b9bf/esp32/flags/cpp_flags -w -Os -DF_CPU=240000000L -DARDUINO=10607 -DARDUINO_ESP32_DEV -DARDUINO_ARCH_ESP32 "-DARDUINO_BOARD=\"ESP32_DEV\"" "-DARDUINO_VARIANT=\"esp32\"" -DARDUINO_PARTITION_default "-DARDUINO_HOST_OS=\"linux\"" "-DARDUINO_FQBN=\"esp32:esp32:esp32\"" -DESP32 -DCORE_DEBUG_LEVEL=0 -DARDUINO_RUNNING_CORE=1 -DARDUINO_EVENT_RUNNING_CORE=1 -DARDUINO_USB_CDC_ON_BOOT=0 @/root/.arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.1-6b1f40b9bf/esp32/flags/defines -I/home/ps/projects/c/arduino/OneWireNg/examples/arduino/DallasTemperature -iprefix /root/.arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.1-6b1f40b9bf/esp32/include/ @/root/.arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.1-6b1f40b9bf/esp32/flags/includes -I/root/.arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.1-6b1f40b9bf/esp32/qio_qspi/include -I/root/.arduino15/packages/esp32/hardware/esp32/3.0.0-alpha2/cores/esp32 -I/root/.arduino15/packages/esp32/hardware/esp32/3.0.0-alpha2/variants/esp32 -I/root/Arduino/libraries/OneWireNg/src @/tmp/arduino/sketches/2EC09C26A960CEA4C81193530AEEE765/build_opt.h /tmp/arduino/sketches/2EC09C26A960CEA4C81193530AEEE765/sketch/DallasTemperature.ino.cpp -o /tmp/arduino/sketches/2EC09C26A960CEA4C81193530AEEE765/sketch/DallasTemperature.ino.cpp.o
| /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/bin/ld: /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/lib/no-rtti/libc.a(lib_a-raise.o):(.literal+0x0): warning: _getpid_r is not implemented and will always fail
| /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/bin/ld: /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/lib/no-rtti/libc.a(lib_a-raise.o):(.literal+0x4): warning: _kill_r is not implemented and will always fail
| /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/bin/ld: /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/lib/no-rtti/libc.a(lib_a-syswrite.o):(.literal+0x4): warning: _write_r is not implemented and will always fail
| /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/bin/ld: /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/lib/no-rtti/libc.a(lib_a-syswrite.o):(.literal+0x0): warning: __getreent is not implemented and will always fail
| /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/bin/ld: /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/lib/no-rtti/crt0.o:(.literal+0x0): undefined reference to `main'
| /root/.arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/esp-12.2.0_20230208/bin/../lib/gcc/xtensa-esp32-elf/12.2.0/../../../../xtensa-esp32-elf/bin/ld: /tmp/cc5Yr0r9.o:(.literal._ZN9OneWireNg8iterator10searchStepEv[_ZN9OneWireNg8iterator10searchStepEv]+0x0): undefined reference to `_ZN9OneWireNg6searchERA8_hb'

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[me-no-dev]

Create a file named build_opt.h in your sketch folder and put the flags in there. That way we do not need to change anything and you do not need to depend on platform.txt

[pstolarz]

@me-no-dev compiler.XXX.extra_flags is a common and documented approach to provide extra flags to the compiler, whereas build_opt.h is not (it's only esp32 and stm32 cores specific). On my CI/CD env I'm testing ~20 cores so build_opt.h doesn't help me. For all cores known to me the compiler.XXX.extra_flags are empty and left for exclusive user usage.

[me-no-dev]

Could you give me some context on what you are testing and how you are overwriting those flags? We could move them and uglify the platform more, but I would like to understand well what is going on and what are the possible use cases.

[pstolarz]

Please look at this workflow lines 65-67. I'm passing extra flags via --build-property "compiler.cpp.extra_flags=$BUILD_FLAGS", where BUILD_FLAGS is set above.

BTW I've overcome this issue by adding -c do BUILD_FLAGS but it's not a solution I like.

[ArminJo]

@me-no-dev
Hi me-no-dev,
it seems, that ALL library developers using CI/CD rely on passing extra flags by using compiler.cpp.extra_flags.

See: arduino/arduino-cli#2683 (comment)

Even though the idea behind the compiler.cpp.extra_flags property was to provided a dedicated property for sole use by the user to inject arbitrary flags into the C++ compilation command, the powerful and flexible Arduino boards platform framework doesn't impose any restrictions on platform developers. Unfortunately some platform developers have pointlessly (because they could instead have simply defined an arbitrary property for the purpose) made use of this property internally.

So ESP is the only core which "breaks" this implicit rule with its 3.x release, effectively disabling CI/CD for library developer.
I can see the reason for using the compiler.cpp.extra_flags in platform.txt, but I am sure you weren't aware of the drawbacks (poor library support in the future) of using this.
Can you do all volunteer developers a favour and move the three -MMD -c from *.extra_flags to *. flags?

[me-no-dev]

will look into it

[me-no-dev]

Will be fixed in the upcoming v3.1.0