handle strange behaviour re: symlinks becoming empty directories

DESCRIPTION

@@ -2,7 +2,7 @@ Package: packrat
 Type: Package
 Title: A Dependency Management System for Projects and their R Package
     Dependencies
-Version: 0.4.3-18
+Version: 0.4.3-19
 Date: 2014-09-02
 Author: Kevin Ushey, Jonathan McPherson, Joe Cheng, JJ Allaire
 Maintainer: Kevin Ushey <kevin@rstudio.com>

R/library-support.R

@@ -47,7 +47,13 @@ symlinkSystemPackages <- function(project = NULL) {
 
     # Bash old symlinks just to ensure this session will be non-stale.
     # TODO: What if multiple R sessions want to run with a single packrat project?
-    if (file.exists(to)) unlink(to)
+    if (file.exists(to) && is.symlink(to))
+      unlink(to)
+
+    # TODO: For some reason, empty directories rather than junction points can
+    # get generated on Windows.
+    if (file.exists(to))
+      unlink(to, recursive = TRUE)
 
     symlink(from, to)
   }, logical(1)))

inst/resources/init-rprofile.R

@@ -1,3 +1,3 @@
-#### -- Packrat Autoloader (version 0.4.3-18) -- ####
+#### -- Packrat Autoloader (version 0.4.3-19) -- ####
 source("packrat/init.R")
 #### -- End Packrat Autoloader -- ####

inst/resources/init.R

@@ -151,7 +151,7 @@ local({
     ## an 'installed from source' version
 
     ## -- InstallAgent -- ##
-    installAgent <- 'InstallAgent: packrat 0.4.3-18'
+    installAgent <- 'InstallAgent: packrat 0.4.3-19'
 
     ## -- InstallSource -- ##
     installSource <- 'InstallSource: source'