Work Around R Windows Bug: Directories with Trailing Slashes Don't Work

[billdenney]

A long-standing bug in R for Windows is that slashes at the end of directory names aren't handled correctly. What I'm reporting below is that R windows bug that is viewed as not to be fixed (https://bugs.r-project.org/bugzilla/show_bug.cgi?id=14721, see bottom of this issue report), but it causes problems with drake and has a simple work-around.

Directory names with trailing slashes appear not to exist while directories without trailing slashes work correctly. Wherever this issue occurs in drake, wrapping the directory name with file.path() will chop off the trailing slash and make it work correctly.

library(drake)

dir.create("c:/tmp/t", recursive=TRUE, showWarnings=FALSE)
make(drake_plan(list.files(path=file_in("c:/tmp/t"))))
#> target drake_target_1
make(drake_plan(list.files(path=file_in("c:/tmp/t/"))))
#> Warning: missing input files:
#>   c:/tmp/t/
#> target drake_target_1

^{Created on 2019-04-30 by the reprex package (v0.2.1)}

The windows inconsistency illustrated:

> file.exists("c:/tmp/")
[1] FALSE
> file.exists("c:/tmp")
[1] TRUE

[wlandau]

Thanks, @billdenney. Should be fixed now.