Remove check for git user.name and user.email to be set?

[traversaro]

In YCMEPHelper in

ycm-cmake-modules/modules/YCMEPHelper.cmake

Lines 320 to 336 in d5c16de

	execute_process(COMMAND ${GIT_EXECUTABLE} config --get user.name
	WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
	RESULT_VARIABLE _error_code
	OUTPUT_VARIABLE _output_name
	OUTPUT_STRIP_TRAILING_WHITESPACE)
	if(NOT NON_INTERACTIVE_BUILD AND _error_code)
	message(FATAL_ERROR "Failed to get git name. Please set it with \"git config --global user.name Firstname Lastname\" or from your favorite git gui.")
	endif()
	execute_process(COMMAND ${GIT_EXECUTABLE} config --get user.email
	WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
	RESULT_VARIABLE _error_code
	OUTPUT_VARIABLE _output_email
	OUTPUT_STRIP_TRAILING_WHITESPACE)
	if(NOT NON_INTERACTIVE_BUILD AND _error_code)
	message(FATAL_ERROR "Failed to get git email. Please set it with \"git config --global user.email name@example.com\" or from your favorite git gui.")
	endif()

(and hence in any ycm-based superbuild that uses git, so basically all of them) there is some code that checks if the git user.name and user.email is set, and if they are not set, raise a fatal error.

This hit (at least me) many times when trying to run the superbuild on vanilla (Docker, GitHub Actions, gitpod, etc etc) machine, and I am afraid that many other users have been affected as well.

As far as I can understand, the only reason why such check is there is to prevent users to actually commit commits with the automatically generated values for user.name and user.email, i.e. creating warnings such as:

Your name and e-mail address were configured automatically based
on your username and hostname. Please check that they are accurate.
You can suppress this message by setting them explicitly. Run the
following command and follow the instructions in your editor to edit
your configuration file:

    git config --global --edit

After doing this, you may fix the identity used for this commit with:

    git commit --amend --reset-author

however, it does not seems to be that have an hard failure whenever somebody is trying to run the superbuild in a clean environment is worth avoiding in some remote case some autogenerated commit metadata.

So, my plan is to remove this check in the next 0.17.0 release of YCM. The idea is to remove the check rather then just do some sort of tick-tock deprecation cycle, as far as I understand, nothing can break if we remove this check.