[Rd] Inconsistant result for normalizePath on Windows

[William Dunlap]

Re the trailing path separator - should file.path() be changed to not
produce doubled path separators when an argument has a trailing path
separator?

Bill Dunlap
TIBCO Software
wdunlap tibco.com


On Mon, Mar 23, 2020 at 9:24 AM Tomas Kalibera <tomas.kalibera using gmail.com>
wrote:

>
> Hi Jiefei,
>
> the change in handling trailing path separators is not on purpose, but
> is a byproduct of a new implementation of normalizePath, which now
> handles symbolic links and normalizes case in long path names. It is not
> documented what happens to trailing separators, and hence portable
> programs should not depend on it. I don't think it is a property that
> should be documented/specified. The behavior of normalizePath is way too
> complicated already and it's result is OS-specific anyway.
>
> In R-devel as well as in 3.6, the trailing separator is preserved when
> the path does not exist - simply, the original path is returned. When
> the path does exist, R-devel removes the trailing separator but R 3.6
> does not, which is because the underlying Windows API call to implement
> it is now different. The new behavior reflects what
> GetFinalPathNameByHandle returns, which is a function now used for
> normalization also in other language runtimes on Windows. I think the
> new behavior is better: paths differing only in the trailing separator
> will be normalized to the same path.
>
> Best
> Tomas
>
> On 3/23/20 4:39 PM, Wang Jiefei wrote:
> > Hi all,
> >
> > I saw a quite surprising result in the devel R when using the function
> > *normalizePath*. If the input is a path to a folder, the function returns
> > an absolute path with/without a slash at the end depending on the
> existence
> > of the folder. I know both results are valid on Windows but this behavior
> > is different than R3.6, I do not know if the change in the devel version
> is
> > made on purpose. Here is a minimal example, suppose that the folder
> > `C:/windows1/` does not exist.
> >
> >    > normalizePath("C:/windows/", mustWork = FALSE)
> > [1] "C:\\Windows"
> >> normalizePath("C:/windows1/", mustWork = FALSE)
> > [1] "C:\\windows1\\"
> >
> >
> > In R 3.6, the return value always ends with a slash if the input ends
> with
> > a slash. From the NEWS file, It seems like there are some changes to
> > *normalizePath* but none of them should be relevant, it might be an
> > unintentional result introduced by the update.
> >
> > Best,
> > Jiefei
> >
> >       [[alternative HTML version deleted]]
> >
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