Warn if Vagrant is run outside of installers

bin/vagrant

@@ -41,6 +41,9 @@ begin
   logger.debug("Creating Vagrant environment")
   env = Vagrant::Environment.new(opts)
 
+  # If we're not in the installer, warn.
+  env.ui.warn(I18n.t("vagrant.general.not_in_installer")) if !Vagrant.in_installer?
+
   # Execute the CLI interface, and exit with the proper error code
   exit(env.cli(ARGV))
 rescue Vagrant::Errors::VagrantError => e

lib/vagrant.rb

@@ -103,6 +103,14 @@ module Vagrant
     c.register([:"2", :provisioner])  { Plugin::V2::Provisioner }
   end
 
+  # This returns a true/false showing whether we're running from the
+  # environment setup by the Vagrant installers.
+  #
+  # @return [Boolean]
+  def self.in_installer?
+    !!ENV["VAGRANT_INSTALLER_ENV"]
+  end
+
   # The source root is the path to the root directory of
   # the Vagrant gem.
   def self.source_root

templates/locales/en.yml

@@ -18,6 +18,13 @@ en:
 
         Old: %{old}
         New: %{new}
+      not_in_installer: |-
+        You appear to be running Vagrant outside of the official installers.
+        Note that the installers are what ensure that Vagrant has all required
+        dependencies, and Vagrant assumes that these dependencies exist. By
+        running outside of the installer environment, Vagrant may not function
+        properly. To remove this warning, install Vagrant using one of the
+        official packages from vagrantup.com.
       upgraded_v1_dotfile: |-
         A Vagrant 1.0.x state file was found for this environment. Vagrant has
         gone ahead and auto-upgraded this to the latest format. Everything