When I devtools::install() a custom in-development package after R CMD checking it (without any errors, warnings or notes) I always get the following error/message (?) for any packages my own package depends on (e.g. with package data.table):
Skipping 1 packages not available: data.table
The in-development package itself seems to work just fine and in the case of data.table reliant functions they also seem to make no problems.
Can I disregard that message? Is it normal behavior? Or am I at risk of running into bigger problems later on in development because of it?
As it seems the problem was persisting due to a choppy internet connection during development, checking and installing the package. After ensuring a stable connection and a fresh R/RStudio restart the message did no longer occur.
So, if you run into a similar problem, one possible cause of the behavior could be your internet connection, leading to R not finding the package in question in your linked repositories.