Is it possible dropping --debugger and --debugger-pipe when debugging cmake scripts?

[zchrissirhcz]

I use CMake Tools extension to debug a cmake script file, test.cmake by writing a launch.json file.

When debugging, test.cmake receives 3 extra arguments:

--debugger
--debugger-pipe
\\.\\pipe\\cmake-debugger-pipe\\9568e66a-5b26-4573-b376-551ad2c48672

In fact, my actual test.cmake only accept some arguments, e.g. update, install, search, etc, neither --debugger nor --debugger-pipe is valid arguments. Can I drop the extra arguments?

I read the document https://github.com/microsoft/vscode-cmake-tools/blob/main/docs/debug.md , but not found solution.

My .vscode/launch.json is:

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "type": "cmake",
            "request": "launch",
            "name": "CMake: Configure",
            "cmakeDebugType": "script",
            "scriptPath": "${workspaceFolder}/test.cmake",
            "scriptArgs": [
                "-DHELLO=WORLD",
                "-DCMAKE_BUILD_TYPE=Debug"
            ],
            "clean": false,
            "configureAll": false
        }
    ]
}

A sample test.cmake is:

message("Welcom to CMake script mode!")
message("Hello, ${HELLO}")

message(STATUS "CMAKE_ARGC: ${CMAKE_ARGC}")
foreach(_arg RANGE ${CMAKE_ARGC})
  message(STATUS "${_arg}: ${CMAKE_ARGV${_arg}}")
endforeach()

function(add_numbers num1 num2 OUTPUT_VAR)
  math(EXPR output "${num1} + ${num2}")
  set(${OUTPUT_VAR} ${output} PARENT_SCOPE)
endfunction()

set(my_result 0)

add_numbers(5 3 my_result)

message("5 + 3 = ${my_result}")
message("bye~")

The output of debugging test.cmake is:

[zchrissirhcz]

Just found the source where extra args are pushed:

https://github.com/microsoft/vscode-cmake-tools/pull/3181/files#diff-debb2b28d6617ee810ad4ca1171ca3ba817ec0aa42dfe921fbfc541c53444412R242-R245

https://github.com/microsoft/vscode-cmake-tools/blob/main/src/debug/debuggerScriptDriver.ts#L25-L30

@gcampbell-msft Is it possible that I remove extra args when debug CMake script?

[gcampbell-msft]

@zchrissirhcz No, the way that the cmake debugger works is that you have to pass these arguments to be able to debug. Is there some other scenario that you're trying to complete that we don't support?

[zchrissirhcz]

It seem like concreteArgs is received in mybuild.cmake, but I expect it only receives scriptArgs.

[zchrissirhcz]

It seems I was wrong. I should read the CMake document, the --debugger and --debugger-pipe is required by CMake since 3.27.

https://cmake.org/cmake/help/latest/manual/cmake.1.html#cmdoption-cmake-debugger

[gcampbell-msft]

OK, --debugger or --debugger-pipe is for debugging, they are required. In order to debug CMake, for script mode, is it possible that in the debugee (mybuild.cmake), the CMAKE_ARGV${_arg} does not includes --debugger and --debugger-pipe?

For this, I don't think that this can be done, because we are assuming the mybuild.cmake is what is desired to be debugged, and in that case the debugger arguments are required. To my knowledge, there is no way to pass arguments without them appearing in the CMAKE_ARGV.

[zchrissirhcz]

I think dropping --debugger and --debugger-pipe is possible. This should be done inside cmake, instead of VSCode CMake Tools extension.

Let me give a similar usage. When using GDB for C/C++ code debugging, and the main.cpp requires an argument, say, an integer.

The command to start GDB with arguments is:

gdb --args a.out 42  

And in main.cpp, it receives a.out and 42, but it won't receive --args.

#include <iostream>  
#include <cstdlib>  // For std::atoi  

int main(int argc, char* argv[]) {  
    // Ensure that we received one argument  
    if (argc != 2) {  
        std::cerr << "Usage: " << argv[0] << " <integer_value>" << std::endl;  
        return 1;  
    }  

    // Convert the received argument to an integer  
    int value = std::atoi(argv[1]);  

    // Print the integer value  
    std::cout << "The provided integer value is: " << value << std::endl;  

    return 0;  
}

[gcampbell-msft]

@zchrissirhcz I can confirm that this would need to be an improvement in cmake itself, because right now even if we put the --debugger or --debugger-pipe argument in front of -P <script>, the script still receives the arguments.

I would direct you to the Kitware site: https://gitlab.kitware.com/cmake/cmake/-/issues, to create an issue there. Thanks!