Problem with overriding mbed_lib.json configuration for private libraries

[byq77]

Problem description

Using mbed_app.json I am able to override configuration for my target that is defined by core mbed framework. However, if I try to override options defined by my own library it won't work.

Reproduction

Content of my lib directory:

lib
├── foo-lib
│   ├── foo.cpp
│   ├── foo.h
│   └── mbed_lib.json
└── README.md

mbed_lib.json looks like this:

{
    "name":"foo-lib",
    "macros":["FOO_STRING_1=\"FOO1\"" , "FOO_STRING_2=\"FOO2\""],
    "config":
    {
        "option":
        {
            "help": "Select foo string",
            "macro_name": "FOO_OPTION",
            "accepted_values": [0,1],
            "value": 0,
            "required": false
        }
    }
}

platform.ini:

[env:core2]
platform = ststm32
framework = mbed
board = core2
build_flags = 
    -I$PROJECTSRC_DIR/TARGET_CORE2
    -D PIO_FRAMEWORK_MBED_RTOS_PRESENT
    -D PIO_FRAMEWORK_EVENT_QUEUE_PRESENT
    -D MBED_BUILD_PROFILE_RELEASE
platform_packages =
    framework-mbed @ ~6.51506.0

core2 is my custom board. mbed_app.json:

{
    "config": {},
    "macros": [],
    "target_overrides": {
        "CORE2": {
            "events.shared-dispatch-from-application": 0,
            "events.shared-eventsize": 512,
            "events.shared-stacksize": 2048,
            "platform.default-serial-baud-rate": 230400,
            "platform.stdio-baud-rate": 230400,
        }
    }
}

My project builds without any problem if I don't override foo-lib option. In addition to that, generated mbed_config.h contains following lines:

// PlatformIO Library Dependency Finder (LDF)
#define FOO_STRING_1 "FOO1"
#define FOO_STRING_2 "FOO2"
#define FOO_OPTION 0

so it seems that mbed_lib.json is processed correctly. However, if I modify mbed_app.json:

{
    "target_overrides": {
        "CORE2": {
            "foo-lib.option": 1,
            ...
        }
    }
}

the build fails with error:

Attempt to override undefined parameter 'foo-lib.option' in 'application[CORE2]'
mbed build API internal error

[byq77]

I found another issue that is connected to the one above. If I add my custom library as dependency using lib_deps (github url) in platformio.ini no mbed configuration is generated despite library containing mbed_lib.json. Also platformio dependency manager adds library.json file to that library:

{
  "name": "core2-imu-driver",
  "version": "0.0.0+20210202130906"
}

If I move said library from libdeps to my project's lib directory the result is the same. However, if I remove the library.json file from that library LDF system successfully generates the configuration.

[Copper-Bot]

Hi,

I confirm the last message from @byq77. The library.json has to be deleted to get PIO generates the configuration from the mbed_lib.json of the lib. Do we have to open a new issue about that ?

I am using PIO 5.2.2 on Windows 10.

[Copper-Bot]

Hello again @byq77,

I just resolve the problem about the mbed_lib.json not used by PIO:
You have to add the right builder in the library.json file, in our case MbedLibBuilder:

{
  "name": "lib_test_pio",
  "version": "0.0.1",
  "description": "test lib to get mbed_lib json working",
  "keywords": "test, pio, mbed_lib",
  "build": {
    "builder": "MbedLibBuilder"
  }
}

I recommend adding the library.json file in your library repository, to get sure PIO will interpret correctly.

But for other libraries around the web that doesn't have a library.json file ... well that could be a problem, because PIO use PlatformIOLibBuilder by default.