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?2?23?(?) 17:15 Tomas Kalibera <tomas.kalibera at 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
sure which behavior is right, let me ask here before filing this to R's
Bigzilla.
On R 4.2.2., we get
[1] "C:/"
However, on R-devel (r83888), we get
[1] "."
?dirname says 'dirname returns the part of the path up to but excluding
last path separator, or "." if there is no path separator,' but I don't
how the root path is supposed to be treated based on this rule (,
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]]