core: Catch plugin load errors and show them to the user ina friendly way

bin/vagrant

@@ -54,14 +54,17 @@ if argv.include?("--debug")
   ENV["VAGRANT_LOG"] = "debug"
 end
 
-# Require some stuff that is NOT dependent on RubyGems
-require "vagrant/shared_helpers"
-
 # Setup our dependencies by initializing Bundler. If we're using plugins,
 # then also initialize the paths to the plugins.
 require "bundler"
 Bundler.setup
 
+# Stdout/stderr should not buffer output
+$stdout.sync = true
+$stderr.sync = true
+
+env = nil
+begin
   require 'log4r'
   require 'vagrant'
   require 'vagrant/cli'
@@ -71,10 +74,6 @@ require 'vagrant/util/platform'
   logger = Log4r::Logger.new("vagrant::bin::vagrant")
   logger.info("`vagrant` invoked: #{ARGV.inspect}")
 
-# Stdout/stderr should not buffer output
-$stdout.sync = true
-$stderr.sync = true
-
   # These will be the options that are passed to initialze the Vagrant
   # environment.
   opts = {}
@@ -118,8 +117,6 @@ opts[:ui_class] ||= Vagrant::UI::Colored
   argv << "--"
   argv += argv_extra
 
-env = nil
-begin
   # Create the environment, which is the cwd of wherever the
   # `vagrant` command was invoked from
   logger.debug("Creating Vagrant environment")
@@ -141,6 +138,8 @@ begin
   # Exit with the exit status from our CLI command
   exit(exit_status)
 rescue Vagrant::Errors::VagrantError => e
+  require 'log4r'
+  logger = Log4r::Logger.new("vagrant::bin::vagrant")
   logger.error("Vagrant experienced an error! Details:")
   logger.error(e.inspect)
   logger.error(e.message)

lib/vagrant.rb

@@ -262,4 +262,10 @@ Vagrant.source_root.join("plugins").children(true).each do |directory|
 end
 
 # If we have plugins enabled, then load those
-Bundler.require(:plugins) if Vagrant.plugins_enabled?
+if Vagrant.plugins_enabled?
+  begin
+    Bundler.require(:plugins)
+  rescue Exception => e
+    raise Vagrant::Errors::PluginLoadError, message: e.to_s
+  end
+end

lib/vagrant/errors.rb

@@ -481,14 +481,6 @@ module Vagrant
       error_key(:plugin_load_error)
     end
 
-    class PluginLoadFailed < VagrantError
-      error_key(:plugin_load_failed)
-    end
-
-    class PluginLoadFailedWithOutput < VagrantError
-      error_key(:plugin_load_failed_with_output)
-    end
-
     class PluginNotFound < VagrantError
       error_key(:plugin_not_found)
     end

templates/locales/en.yml

@@ -531,19 +531,10 @@ en:
 
         %{conflicts}
       plugin_load_error: |-
-        The plugin "%{plugin}" could not be found. Please make sure that it is
-        properly installed via `vagrant plugin`. Note that plugins made for
-        Vagrant 1.0.x are not compatible with 1.1+ and this error will likely
-        continue to show when you use `plugin install` with a 1.0.x plugin.
-      plugin_load_failed: |-
-        Failed to load the "%{plugin}" plugin. View logs for more details.
-      plugin_load_failed_with_output: |-
-        Failed to load the "%{plugin}" plugin. The output from loading
-        the plugin is shown below. View the logs for complete details.
+        The plugins failed to load properly. The error message given is
+        shown below.
 
-        stdout: %{stdout}
-
-        stderr: %{stderr}
+        %{message}
       plugin_not_found: |-
         The plugin '%{name}' could not be found. Please install this plugin
         prior to attempting to do anything with it.