Configuring CMake fails

[stephenberry]

Configuring CMake with stdexec as a dependency works the first time entirely from scratch (on Mac/Windows). However, subsequent calls to CMake will produce the following error:

CMake Error at build/_deps/stdexec-src/test/CMakeLists.txt:140 (include):
  include could not find requested file:

    /contrib/Catch.cmake


CMake Error at build/_deps/stdexec-src/test/CMakeLists.txt:142 (catch_discover_tests):
  Unknown CMake command "catch_discover_tests".

Deleting the cache seems to work, except on Linux which seems to have this problem more persistently.

We're configuring with STD_BUILD_TESTS turned off.

[ericniebler]

stdexec doesn't use STD_BUILD_TESTS for anything. it builds tests if either of STDEXEC_BUILD_TESTS or BUILD_TESTING is set to a truthy value.

i have never seen this error, but then again i don't typically build stdexec as a dependency. i'll see if i can repro when i have a chance.

[wsberry]

I am finding the bug to be intermittent. Two observations when this error occurs:

1. the catch repo was not included in the CMAKE_BINARY_DIR/_deps folder (it was not downloaded)
2. the path error indicates contrib/Catch.cmake when it should be something line ${CMAKE_BINARY_DIR}/_deps/catch2-src/contrib/Catch.cmake

[wsberry]

I avoided this error by not using CPM in my project:

function (fetch_stdexec)
  set(branch_or_tag "main")
  set(url "https://github.com/NVIDIA/stdexec.git")
  set(target_folder "${CMAKE_BINARY_DIR}/_deps/stdexec-src")

  if (NOT EXISTS ${target_folder})
    execute_process(
        COMMAND git clone --depth 1 --branch "${branch_or_tag}" --recursive "${url}" "${target_folder}"
        WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
        RESULT_VARIABLE exec_process_result
        OUTPUT_VARIABLE exec_process_output
    )
    if(NOT exec_process_result EQUAL "0")
        message(FATAL_ERROR "Git clone failed: ${exec_process_output}")
    else()
        message(STATUS "Git clone succeeded: ${exec_process_output}")
    endif()
  endif()

  set(stdexec_SOURCE_DIR ${target_folder} CACHE INTERNAL "stdexec source folder" FORCE)
  set(stdexec_INCLUDE_DIR ${target_folder}/include CACHE INTERNAL "stdexec include folder" FORCE)

    #[[ Switched from using:
    include(FetchContent)

    FetchContent_Declare(
        stdexec
        GIT_REPOSITORY https://github.com/NVIDIA/stdexec.git
        GIT_TAG main
        GIT_SHALLOW TRUE
    )

    set(STDEXEC_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)

    FetchContent_MakeAvailable(stdexec)
    #]]

endfunction()

[ednolan]

This oneliner reproduces the issue:

docker run ubuntu:24.04 bash -c 'apt update ; apt install -y cmake git g++ ; mkdir repro ; cd repro ; git clone https://github.com/NVIDIA/stdexec.git ; git -C stdexec checkout bfc2610b2e92e467174f83fc9c573cfb3dec1196 ;  echo -e "cmake_minimum_required(VERSION 3.25)\nproject(repro CXX)\ninclude(CTest)\nadd_subdirectory(stdexec)" > CMakeLists.txt ; mkdir build ; cd build ; cmake ..'

My pull request here attempts to resolve it: #1380