On Wed, Jul 20, 2016 at 3:52 AM, Martin Maechler <maech...@stat.math.ethz.ch> wrote: >>>>>> Jeroen Ooms <jeroeno...@gmail.com> >>>>>> on Wed, 20 Jul 2016 10:26:19 +0200 writes: > > > On Tue, Jul 19, 2016 at 6:46 PM, Kevin Ushey <kevinus...@gmail.com> > wrote: > >> R fails to install a package from source over a pre-existing package > >> when the path to that package is a symlink, rather than a directory. > >> ... > >> I don't think anyone's reported this being an issue before > > > I ran into this as well a while back: > > https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=16725 > > I've now at least "acknowledged" that bug report. > and have looked into changing the is_subdir() function so it > returns TRUE in the case of a symlink [on those platforms where > Sys.readlink() "works", i.e., supposedly not on Windows; however > that maybe sufficient to close that bug report and also Kevin's > issue, right ?] > > However, Kevin, in his posting, continues > > > I guess my wish here would be that R would check if any file already > > existed at the 'instdir' path, and if it existed and was a symlink, R > > would remove that symlink before install. > > are you sure? > I think ... and from what you mention below ("packrat") it would > rather be important to *keep* the symlink, and install to > whereever the symlink is pointing, no ?
For packrat's case at least, removing the symlink and installing to a newly-created directory within the library would be fine -- later, when a user wants to 'save the state' of their library, they would call 'packrat::snapshot()', and that call would take care of moving the newly-installed package to the cache and restoring the symlink as required. That said, installing within the symlinked directory would definitely be nice :-) I just thought the request might be out of scope. > > It could happen before creating the directory, e.g. here: > > > > https://github.com/wch/r-source/blob/62f5acbdbdf36e1fc618510312125d1677d79941/src/library/tools/R/install.R#L277-L281 > > > One thing that was a bit surprising to me -- R does not remove a > > pre-existing package installation if it exists (when installing from > > source), it merely installs over it, so files / artifacts from a > > previous package installation could be left over after installing a > > new package. It seems this is not a problem in practice since I don't > > think anyone's reported this being an issue before, but for hygiene it > > seems like a pre-existing directory could / should be removed when > > installing a new package. (It appears that R does clear out a > > pre-existing directory when downloading and installing a package > > binary directly from CRAN.) > > Well, at least with update.packages() it seems natural to me > that R would not just remove all previous parts there .. > > > For motivation: I bumped into this when attempting to implement a > > package caching feature with packrat. A packrat project using a global > > cache will have a (private) R library containing symlinks to R package > > installations in a separate, global library. This allows projects to > > effectively be isolated from one another, while avoiding duplication > > of packages used across multiple projects. > > Yes, I found this a nice feature when I heard about packrat. > > But then, really R should *not* remove the symlink and create a > regular subdirectory in that library there ! I agree this would be ideal, I just thought this request might be out of scope, since the typical use case for R libraries is a directory-of-directories, not a directory-of-symlinks-to-directories (although packrat has had a lot of success with the second scenario!) Thanks, Martin! > > Unfortunately, some packrat > > users bump into this when attempting to update a package that has > > entered the cache (and so is a symlink in their R library). > > > Thanks for your time, > > Kevin > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
