[R-win] Bug 17159 - recursive dir.create() fails on windows shares due to permissions (MMaechler: Resending to R-windows@R-pr..)

On 16 Jan 2018, at 17:52 , Joris Meys <jorismeys at gmail.com> wrote:

Hi all,

I ran into this exact issue yesterday during the exam of statistical
computing. Users can install packages in a user library that R tries to
create automatically on the network drive of the student. But that doesn't
happen as the unc path is not read correctly, leading to R attempting to
create a local directory and being told it has no right to do so.

That is an older version of R though (3.3), but I'm wondering whether I
would ask our IT department to just update R on all these computers to the
latest version, or if we have to look for another solution.

Cheers
Joris

On Mon, Jan 8, 2018 at 1:43 PM, Thompson, Pete <Pete.Thompson at iqvia.com>
wrote:

Hi, I?d like to ask about bug 17159:

https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17159

I can confirm that I see exactly this bug when using dir.create on paths
of UNC form (\\server\share\xxx), with the recursive flag set. I?m seeing
this when attempting to use install.packages with such a path (which I know
isn?t supported, but would be great if it was!). I can see that a patch has
been suggested for the problem and from looking at the source code I
believe it?s a correct fix. Is there a possibility of getting this patch
included?

The existing logic for Windows recursive dir.create (platform.c lines
2209-22203) appears to be:
- Skip over any \\share at the start of the directory name
- Loop while there are pieces of directory name left (i.e. we haven?t hit
the last \ character)
 = Find the next portion of the directory name (up to the next \
character)
 = Attempt to create the directory (unless it is of the form x: - i.e. a
drive name)
 = Ignore any ?already exists? errors, otherwise throw an error

This logic appears flawed in that it skips \\share which isn?t a valid
path format (according to https://msdn.microsoft.com/en-
us/library/windows/desktop/aa365247(v=vs.85).aspx ). Dredging my memory,
it?s possible that \\share was a supported format in very old versions of
Windows, but it?s been a long time since the UNC format came in. It?s also
possible that \\share is a valid format in some odd environments, but the
UNC format is far more widely used.

The patch suggested by Evan Cortens is simply to change the skip logic to
skip over \\server\share instead of \\share. This will certainly fix the
common use case of using UNC paths, but doesn?t attempt to deal with all
the more complex options in Microsoft?s documentation. I doubt many users
would ask for the complex cases, but the basic UNC format would be of wide
applicability.

Thanks
Pete Thompson
Director, Information Technology
Head of Spotfire Centre of Excellence
IQVIA

-- 
Joris Meys
Statistical consultant

Department of Data Analysis and Mathematical Modelling
Ghent University
Coupure Links 653, B-9000 Gent (Belgium)
<https://maps.google.com/?q=Coupure+links+653,%C2%A0B-9000+Gent,%C2%A0Belgium&entry=gmail&source=g>

-----------
Biowiskundedagen 2017-2018
http://www.biowiskundedagen.ugent.be/

-------------------------------
Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php

	[[alternative HTML version deleted]]