local_package_deps: throw clear warning when `pkgdir` is not valid?

[MatthieuStigler]

This is a small detail, but it would be nice to have local_package_deps fail in a cleaner way when pkgdir is not found?

Currently, this triggers the correct message, but only as warning, then triggering a subsequent error:

#> Warning in normalizePath(path): path[1]="wrongpath": No such file or directory #> Error in if (!is_dir(path)) {: missing value where TRUE/FALSE needed

library(remotes)
packageVersion("remotes")
#> [1] '2.4.2.9000'
local_package_deps("wrongpath")
#> Warning in normalizePath(path): path[1]="wrongpath": No such file or directory
#> Error in if (!is_dir(path)) {: missing value where TRUE/FALSE needed

^{Created on 2023-05-10 with reprex v2.0.2}

[gaborcsardi]

A PR is welcome!

[MatthieuStigler]

ok, just added mustWork = TRUE in normalizePath, now warning becomes error