Have usethis::proj_path_prep() use fs::path_abs(fs::path_expand()) instead of fs::path_real()

[jimhester]

usethis currently uses fs::path_real() to determine the project path, however this poses problems when the path is a mapped network drive on Windows, because the root no longer can be calculated relative to the input path.

I map my R projects folder to my windows VM, so I run into this situation often.

I propose to instead use fs::path_abs(fs::path_expand()).

usethis::proj_set("Z:/projects/remotes")
#>  Setting active project to '//vmware-host/Shared Folders/projects/remotes'
usethis::use_test()
#> Error: Open file must be in the 'R/' directory of the active package.
#> * Actual path: 'Z:/projects/remotes/R/submodule.R'
fs::path_real("Z:/projects/remotes/R/submodule.R")
#> //vmware-host/Shared Folders/projects/remotes/R/submodule.R
fs::path_abs(fs::path_expand("Z:/projects/R/submodule.R"))
#> Z:/projects/R/submodule.R

fs::path_real("~/Links")
#> C:/Users/IEUser/Links
fs::path_abs(fs::path_expand("~/Links"))
#> C:/Users/IEUser/Links

Created on 2018-10-12 by the reprex package (v0.2.0).

[jennybc]

When I first did this, I did that survey of the fs path expanding/normalizing/realizing functions and how they overlap with each other (or do not).

I concluded that fs::path_real() was the best plan, but my confidence was far from 100%. I will look back at the commits to see if I recorded anything interesting.

Barring some discovery that we must discuss ... sure, I'm happy to make this switch.

[jennybc]

Seems to be the most important commit/comment: 29397a6#r195969953

I see no specific reason to prefer fs::path_real() (current) over fs::path_abs(fs::path_expand()) (your proposal).

[jennybc]

See #485 why this isn't quite simple. I am caught between path handling in rprojrooot (definitely uses normalizePath()) and rstudioapi (not sure what I can count on).

What if we leave proj_path_prep() as is and use it instead of path_expand_r() here?

usethis/R/r.R

Line 42 in 44dd72c

active_file <- path_expand_r(rstudioapi::getSourceEditorContext()$path)

I do not have a Windows VM at the moment to test with.