In https://github.com/backdrop/backdrop-issues/issues/4640 we came across an issue when modules didn't have a 'type' value set in their info file. One solution was proposed to log a warning in the DB log when this happened, so that people would be aware of this and (hopefully) make the module maintainers aware so they can update their modules.

But since further discussion about exactly what and when to log these messages was needed, we're opening this separate issue to discuss and possibly implement more widely.

Initially we thought to log these messages from installer_browser_installation_enable_form() where the issue was first observed, however it was since proposed to implement a more-generic solution by implementing the logging in _system_rebuild_module_data() instead.

What do others think? Should we be logging warnings when a project doesn't have a 'type' set? If so, where should this happen?

GitHub Issue #: 
4866