>>>>> 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 ?
> 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 !
> 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
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