I think the namespace one is actually a legit bug. namespace_imports is only called here:
https://github.com/jimhester/lintr/blob/fa05ceb2bf967ddad9230e25879b95084c80b0dc/R/object_name_linters.R#L57
without an argument. the default is to run find_package() (again without argument), but there's no default, so normalizePath always fails:
https://github.com/jimhester/lintr/blob/fa05ceb2bf967ddad9230e25879b95084c80b0dc/R/lint.R#L287
In namespace_imports this error happens within tryCatch so it just returns NULL.
I'm not sure the intended behavior but certainly the above is not it 😃
Originally posted by @MichaelChirico in #639 (comment)