[Rd] Undocumented change of dirname("C:/") on R-devel on Windows

[Yihui Xie]

Thanks a lot! I can confirm that it has been fixed indeed.

Regards,
Yihui



On Mon, Feb 27, 2023 at 1:14 PM Tomas Kalibera <tomas.kalibera using gmail.com>
wrote:

>
> On 2/27/23 17:02, Yihui Xie wrote:
>
> Hi Tomas,
>
> There has been an R CMD check error with xfun and r-devel on Windows for a
> while:
> https://www.r-project.org/nosvn/R.check/r-devel-windows-x86_64/xfun-00check.html
> Basically it means that the following would return TRUE before:
>
>   normalizePath('a/b', mustWork = FALSE) == normalizePath('./a/b',
> mustWork = FALSE)
>
> but it became FALSE at some point in r-devel. I think 'a/b' and './a/b`
> should be treated as the same path. Does that make sense? Thanks!
>
> Thanks a lot for spotting and reporting this, fixed in R-devel.
> Normalization of non-existent paths was broken.
>
> Best
> Tomas
>
>
> Regards,
> Yihui
> --
> https://yihui.org
>
>
> On Thu, Feb 23, 2023 at 11:44 PM Hiroaki Yutani <yutani.ini using gmail.com>
> wrote:
>
>> I confirmed the revert fixed my failing test. Thanks!
>>
>> 2023年2月23日(木) 20:12 Hiroaki Yutani <yutani.ini using gmail.com>:
>>
>> > Thanks for the prompt response, I'll confirm it after the new R-devel
>> > binary is available.
>> > Also, thanks for the detailed explanation. I agree with you in general.
>> >
>> > > "/" in "C:/" is a path separator or not, and whether it is trailing or
>> > not
>> >
>> > It seems a Windows' path basically consists of two components; a drive
>> > specification (e.g., C:) and the directory structure within the drive.
>> What
>> > I learned today is that both "C:/" and "C:" are valid path
>> specifications,
>> > but refer to different locations; "C:" is not the root directory of the
>> > drive, but just a relative path [1]. So, I agree with you that the
>> basename
>> > of "C:/" should be "C:/". However, at the same time, I don't feel this
>> is
>> > worth a breaking change, so I think we can preserve the current (R
>> 4.2.2)
>> > behavior.
>> >
>> > [1]:
>> >
>> https://learn.microsoft.com/en-us/dotnet/standard/io/file-path-formats#apply-the-current-directory
>> >
>> > Best,
>> > Yutani
>> >
>> > 2023年2月23日(木) 17:15 Tomas Kalibera <tomas.kalibera using gmail.com>:
>> >
>> >>
>> >> On 2/23/23 03:27, Hiroaki Yutani wrote:
>> >> > Hi,
>> >> >
>> >> > I found dirname() behaves differently on R-devel on Windows. Since
>> I'm
>> >> not
>> >> > sure which behavior is right, let me ask here before filing this to
>> R's
>> >> > Bigzilla.
>> >> >
>> >> > On R 4.2.2., we get
>> >> >
>> >> >      > dirname("C:/")
>> >> >      [1] "C:/"
>> >> >
>> >> > However, on R-devel (r83888), we get
>> >> >
>> >> >      > dirname("C:/")
>> >> >      [1] "."
>> >> >
>> >> > ?dirname says 'dirname returns the part of the path up to but
>> excluding
>> >> the
>> >> > last path separator, or "." if there is no path separator,' but I
>> don't
>> >> see
>> >> > how the root path is supposed to be treated based on this rule (,
>> >> whether
>> >> > it's WIndows or UNIX-alike).
>> >> Thanks for spotting the difference, I've reverted to the previous
>> >> behavior, the change was unintentional. If you spot any other
>> suspicious
>> >> changes in behavior in file-system operations, please report.
>> >> > What should we expect as the return value of dirname("C:/")? I feel
>> the
>> >> > current behavior on R 4.2.2 is right, but I'd like to confirm.
>> >>
>> >> I also think the old behavior is better, even though it could be argued
>> >> whether the "/" in "C:/" is a path separator or not, and whether it is
>> >> trailing or not. But the behavior is in line with Unix where dirname of
>> >> "/" is also "/". Msys2 would return "C:".
>> >>
>> >> If  "/" in "C:/" is a path separator but not a trailing path separator,
>> >> then basename("C:/") should probably be "" and not "C:", and this would
>> >> be in line with what R does on Unix. However, to be in line with Unix,
>> I
>> >> think the basename of "C:/" should be "C:/". Yet, Msys2 returns "C:"
>> >> which is what R does now.
>> >>
>> >> So what these functions should do on Windows is definitely tricky. In
>> >> either case the behavior is now again as in R 4.2.2.
>> >>
>> >> Best
>> >> Tomas
>> >>
>> >> >
>> >> > Best,
>> >> > Yutani
>> >> >
>> >> >       [[alternative HTML version deleted]]
>> >> >
>> >> > ______________________________________________
>> >> > R-devel using r-project.org mailing list
>> >> > https://stat.ethz.ch/mailman/listinfo/r-devel
>> >>
>> >
>>
>>         [[alternative HTML version deleted]]
>>
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