Removing LinkingTo Packages After Installation

cderv · February 2, 2019, 8:32am

For future reference,and regarding cross posting policy, this topic has also been post on github

Can I remove BH after installing dplyr?

opened 11:48PM - 01 Feb 19 UTC

closed 10:27AM - 02 Feb 19 UTC

I know there are several related threads of conversation here and elsewhere conc…erning the dependency of `dplyr` on `BH` (e.g. [here](https://github.com/tidyverse/dplyr/issues/3497), [here](https://github.com/tidyverse/dplyr/pull/3672), and [here](https://github.com/tidyverse/dplyr/pull/3674)). I also posted about this on [Rstudio Community](https://community.rstudio.com/t/removing-linkingto-packages-after-installation/22327) and [Stack Overflow](https://stackoverflow.com/questions/54335329/can-i-remove-linkingto-dependencies-after-installation-of-an-r-package), but I haven't really made any headway on a concrete answer. I know that Writing R Extensions is pretty explicit about the purpose of LinkingTo, but its material is a little over my head so I'll have to beg your patience, because I know my confusion is mostly a result of my limited understanding. I'm working on a use case that is space-sensitive, specifically running a data pipeline in R on an AWS Lambda. An AWS Lambda function is restricted to 250MB. Because of that, we remove the `BH` package after `dplyr` has been installed - it's simply too large to use in an AWS Lambda function. This hasn't created any problems for us, but I'm trying to better understand whether we just happen to not be using any functions of `dplyr` that depend on `BH` or if it's perhaps because the `dplyr` dependency on `BH` is only a compile-time dependency. I am unclear on the specific meaning and implication of a LinkingTo dependency vs, for example, a Depends or Imports. The explanations of LinkingTo dependencies that I've found (including that in Writing R Extensions) have sometimes given me the sense that LinkingTo dependencies are necessary for installation of the package, after which any dependent code has been wrapped in the installed package through static linking so that there is no runtime dependency. Other times it seems more ambiguous and that there can still be runtime dependencies with a LinkingTo dependency. **My general question is:** can LinkingTo dependencies be removed after the package that depends on them has been installed without runtime consequences as long as the dependency isn't also listed as Depends, Imports, etc.? **My specific question is:** is it safe to remove `BH` after installation of `dplyr` is complete or will it break certain functions? If it would break certain functions, will they break "loudly" such that we would know that an error has occurred and can simply choose alternative approaches to accomplishing the goal? As I mentioned, we've already removed `BH` and haven't seen any negative impacts, but this is just the first generation of this pipeline and I'd like to know what we're walking into as we expand its capabilities. Any advice on this would be much appreciated!