[R-pkg-devel] Wrong mailing list: Could the 100 byte path length limit be lifted?

[Ben Bolker]

  FWIW the R-windows FAQ says:

Yet another complication is a 260 character limit on the length of the 
entire path name imposed by Windows. The limit applies only to some 
system functions, and hence it is possible to create a long path using 
one application yet inaccessible to another. It is sometimes possible to 
reduce the path length by creating a drive mapping using subst and 
accessing files via that drive. As of Windows 10 version 1607 and R 4.3, 
one can remove this limit via Windows registry by setting 
Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\LongPathsEnabled 
to 1. Long paths still may not always work reliably: some applications 
or packages may not be able to work with them and Windows cannot execute 
an application with long path as the current directory.

   I'm having trouble finding the specific check for path lengths > 100 
in the R source tree.  It would be helpful to have the exact wording of 
the NOTE/WARNING (?) that is thrown ...  (I know I could make my own 
mini-package with a long path length in it somewhere but ...)

   cheers
    Ben Bolker

On 2023-12-12 2:57 p.m., Simon Urbanek wrote:
> Justin,
> 
> now that you clarified what you are actually talking about, this is a question about the CRAN policies, so you should really direct it to the CRAN team as it is their decision (R-devel would be appropriate if this was a limitation in R itself, and R-package-devel would be appropriate if you wanted help with refactoring to adhere to the policy). There are still path limits on various platforms (even if they are becoming more rare), so I'd personally question the source rather than the policy, but then your email was remarkably devoid of any details.
> 
> Cheers,
> Simon
> 
> 
>> On Dec 13, 2023, at 6:03 AM, McGrath, Justin M <jmcgrath using illinois.edu> wrote:
>>
>> When submitting a package to CRAN, it is required that path names be shorter than 100 bytes, with the reason that paths longer than that cannot be made into portable tar files. This error is reported by `R CMD check --as-cran`. Since this pertains only to developing packages, this seemed like the appropriate list, but if you don't think so, I can instead ask on R-devel.
>>
>> Best wishes,
>> Justin
>>
>> ________________________________________
>> From: Martin Maechler <maechler using stat.math.ethz.ch>
>> Sent: Tuesday, December 12, 2023 10:13 AM
>> To: McGrath, Justin M
>> Cc: r-package-devel using r-project.org
>> Subject: Wrong mailing list: [R-pkg-devel] Could the 100 byte path length limit be lifted?
>>
>>>>>>> McGrath, Justin M
>>>>>>>     on Tue, 12 Dec 2023 15:03:28 +0000 writes:
>>
>>> We include other software in our source code. It has some long paths so a few of the files end up with paths longer than 100 bytes, and we need to manually rename them whenever we pull in updates.
>>> The 100 byte path limit is from tar v7, and since
>>> POSIX1.1988, there has not been a path length limit. That
>>> standard is 35 years old now, so given that there is
>>> probably no one using an old version of tar that also
>>> wants to use the latest version of R, could the 100 byte
>>> limit be lifted? Incidentally, I am a big proponent of
>>> wide, long-term support, but it's hard to see that this
>>> change would negatively impact anyone.
>>
>>> Best wishes,
>>> Justin
>>
>> Wrong mailing list:
>>
>> This is a topic for R-devel,  not at all R-package-devel,
>> but be more accurate in what you are talking about, only between
>> the line I could read that it is about some variants of using
>> 'tar'.
>>
>> Best regards,
>> Martin
>> ---
>>
>> Martin Maechler
>> ETH Zurich  and  R Core team
>>
>> ______________________________________________
>> R-package-devel using r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-package-devel
>>
> 
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