OVMS3-idf/tools/cmake/git_submodules.cmake

find_package(Git)

if(NOT GIT_FOUND)
  message(WARNING "Git executable was not found. Git submodule checks will not be executed. If you have any build issues at all, start by adding git executable to the PATH and rerun cmake to not see this warning again.")

  function(git_submodule_check root_path)
    # no-op
  endfunction()
else(NOT GIT_FOUND)

  function(git_submodule_check root_path)

    execute_process(
      COMMAND ${GIT_EXECUTABLE} submodule status
      WORKING_DIRECTORY ${root_path}
      OUTPUT_VARIABLE submodule_status
      )

    # git submodule status output not guaranteed to be stable,
    # may need to check GIT_VERSION_STRING and do some fiddling in the
    # future...

    lines2list(submodule_status)

    foreach(line ${submodule_status})
      string(REGEX MATCH "(.)[0-9a-f]+ ([^\( ]+) ?" _ignored "${line}")
      set(status "${CMAKE_MATCH_1}")
      set(submodule_path "${CMAKE_MATCH_2}")

      if("${status}" STREQUAL "-")  # missing submodule
        message(STATUS "Initialising new submodule ${submodule_path}...")
        execute_process(
          COMMAND ${GIT_EXECUTABLE} submodule update --init --recursive ${submodule_path}
          WORKING_DIRECTORY ${root_path}
          RESULT_VARIABLE git_result
          )
        if(git_result)
          message(FATAL_ERROR "Git submodule init failed for ${submodule_path}")
        endif(git_result)

      elseif(NOT "${status}" STREQUAL " ")
        message(WARNING "Git submodule ${submodule_path} is out of date. Run 'git submodule update --init --recursive' to fix.")
      endif()

      # Force a re-run of cmake if the submodule's .git file changes or is changed (ie accidental deinit)
      get_filename_component(submodule_abs_path ${submodule_path} ABSOLUTE BASE_DIR ${root_path})
      set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${submodule_abs_path}/.git)
      # same if the HEAD file in the submodule's directory changes (ie commit changes). This will at least prit the 'out of date' warning
      set(submodule_head "${root_path}/.git/modules/${submodule_path}/HEAD")
      if(EXISTS "${submodule_head}")
        set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${submodule_head})
      endif()

    endforeach()
  endfunction(git_submodule_check)

endif(NOT GIT_FOUND)