llvm/cmake/modules/VersionFromVCS.cmake

# Adds version control information to the variable VERS. For
# determining the Version Control System used (if any) it inspects the
# existence of certain subdirectories under SOURCE_DIR (if provided as an
# extra argument, otherwise uses CMAKE_CURRENT_SOURCE_DIR).

function(get_source_info path revision repository)
  find_package(Git QUIET)
  if(GIT_FOUND)
    execute_process(COMMAND ${GIT_EXECUTABLE} rev-parse --git-dir
      WORKING_DIRECTORY ${path}
      RESULT_VARIABLE git_result
      OUTPUT_VARIABLE git_output
      ERROR_QUIET)
    if(git_result EQUAL 0)
      string(STRIP "${git_output}" git_output)
      get_filename_component(git_dir ${git_output} ABSOLUTE BASE_DIR ${path})
      execute_process(COMMAND ${GIT_EXECUTABLE} rev-parse HEAD
        WORKING_DIRECTORY ${path}
        RESULT_VARIABLE git_result
        OUTPUT_VARIABLE git_output)
      if(git_result EQUAL 0)
        string(STRIP "${git_output}" git_output)
        set(${revision} ${git_output} PARENT_SCOPE)
      endif()
      execute_process(COMMAND ${GIT_EXECUTABLE} rev-parse --abbrev-ref --symbolic-full-name @{upstream}
        WORKING_DIRECTORY ${path}
        RESULT_VARIABLE git_result
        OUTPUT_VARIABLE git_output
        ERROR_QUIET)
      if(git_result EQUAL 0)
        string(REPLACE "/" ";" branch ${git_output})
        list(GET branch 0 remote)
      else()
        set(remote "origin")
      endif()
      execute_process(COMMAND ${GIT_EXECUTABLE} remote get-url ${remote}
        WORKING_DIRECTORY ${path}
        RESULT_VARIABLE git_result
        OUTPUT_VARIABLE git_output
        ERROR_QUIET)
      if(git_result EQUAL 0)
        # Passwords or tokens should not be stored in the remote URL at the
        # risk of being leaked. In case we find one, error out and teach the
        # user the best practices.
        string(REGEX MATCH "https?://[^/]*:[^/]*@.*"
          http_password "${git_output}")
        if(http_password)
          message(SEND_ERROR "The git remote repository URL has an embedded \
password. Remove the password from the URL or use \
`-DLLVM_FORCE_VC_REPOSITORY=<URL without password>` in order to avoid \
leaking your password (see https://git-scm.com/docs/gitcredentials for \
alternatives).")
        endif()
        # GitHub token formats are described at:
        # https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/about-authentication-to-github#githubs-token-formats
        string(REGEX MATCH
          "https?://(gh[pousr]|github_pat)_[^/]+@github.com.*"
          github_token "${git_output}")
        if(github_token)
          message(SEND_ERROR "The git remote repository URL has an embedded \
GitHub Token. Remove the token from the URL or use \
`-DLLVM_FORCE_VC_REPOSITORY=<URL without token>` in order to avoid leaking \
your token (see https://git-scm.com/docs/gitcredentials for alternatives).")
        endif()

        string(STRIP "${git_output}" git_output)
        set(${repository} ${git_output} PARENT_SCOPE)
      else()
        set(${repository} ${path} PARENT_SCOPE)
      endif()
    endif()
  else()
    message(WARNING "Git not found. Version cannot be determined.")
  endif()
endfunction()