[R-pkg-devel] Removing packages files

[Henrik Bengtsson]

As a first step, this sounds like something for the 'tools' package,
e.g. tools::cleanup_R_user_dir() that wipes package subfolders of
packages no longer installed, or the specified package, iff given.
With that in place, one could argue for adding a 'cleanup' argument to
remove.packages() that use the former.

Agree, it would be neat if a package could clean up after itself when
uninstalled.

/Henrik

On Thu, Jan 2, 2025 at 1:37 PM Lluís Revilla <lluis.revilla using gmail.com> wrote:
>
> Dear Duncan,
>
> Thank you for your answer. I checked again and made a mock package
> that removes a file with .onDetach.
> The file was not removed upon uninstalling the package.
>
> Lluís
>
> On Thu, 2 Jan 2025 at 17:23, Duncan Murdoch <murdoch.duncan using gmail.com> wrote:
> >
> > On 2025-01-02 9:55 a.m., Lluís Revilla wrote:
> > > Hi list,
> > >
> > > I am developing a package that will download some data, and I'd like
> > > to store it locally to not recalculate it often.
> > > The CRAN policy requires tools::R_user_dir to be used and "the
> > > contents are actively managed (including removing outdated material)"
> > > or using TMPDIR but "such usage should be cleaned up".
> > >
> > > When loading a package there is .onLoad or .onAttach to fill or check
> > > those files and other settings required for a package. Is there
> > > something for when a package is removed?
> > >
> > > I found some related functions like .Last or reg.fnalizer and setHook
> > > or packageEvent but they are about closing a session or don't have a
> > > specific event for when uninstalling packages via (remove.packages). I
> > > appreciate any feedback, thanks in advance.
> > >
> >
> > Yes, those are described in section "1.5.3 Load hooks" of writing R
> > extensions:
> >
> > "Packages can use a .onDetach or .Last.lib function (provided the latter
> > is exported from the namespace) when detach is called on the package. It
> > is called with a single argument, the full path to the installed
> > package. There is also a hook .onUnload which is called when the
> > namespace is unloaded (via a call to unloadNamespace, perhaps called by
> > detach(unload = TRUE)) with argument the full path to the installed
> > package’s directory. Functions .onUnload and .onDetach should be defined
> > in the namespace and not exported, but .Last.lib does need to be exported."
> >
> > Duncan Murdoch
> >
>
> ______________________________________________
> R-package-devel using r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-package-devel