core: all symlinks for synced folders are expanded [GH-3444]

CHANGELOG.md

@@ -17,6 +17,8 @@ BUG FIXES:
       code zero. [GH-3420]
   - core: Adding a box from a network share has nice error on Windows. [GH-3279]
   - core: Setting an ID on a provisioner now works. [GH-3424]
+  - core: All synced folder paths containing symlinks are fully
+      expanded before sharing. [GH-3444]
   - commands/package: Nice error if includes contain symlinks. [GH-3200]
   - commands/rsync-auto: Don't crash if the machine can't be communicated
       to. [GH-3419]

lib/vagrant/action/builtin/synced_folders.rb

@@ -33,7 +33,9 @@ module Vagrant
           # it does not exist on host
           folders.each do |_, fs|
             fs.each do |id, data|
-              data[:hostpath] = File.expand_path(data[:hostpath], env[:root_path])
+              data[:hostpath] = File.expand_path(
+                data[:hostpath], env[:root_path])
+              data[:hostpath] = File.realpath(data[:hostpath])
 
               # Create the hostpath if it doesn't exist and we've been told to
               if !File.directory?(data[:hostpath]) && data[:create]