Add a privileged scope that allows email addresses to be returned

app/controllers/application_controller.rb

@@ -395,4 +395,10 @@ class ApplicationController < ActionController::Base
 
     referer.to_s
   end
+
+  def scope_enabled?(scope)
+    doorkeeper_token&.includes_scope?(scope) || current_token&.includes_scope?(scope)
+  end
+
+  helper_method :scope_enabled?
 end

app/views/api/users/_user.json.jbuilder

@@ -65,5 +65,7 @@ json.user do
         json.count user.sent_messages.size
       end
     end
+
+    json.email user.email if scope_enabled?(:read_email)
   end
 end

app/views/api/users/_user.xml.builder

@@ -40,5 +40,6 @@ xml.tag! "user", :id => user.id,
                            :unread => user.new_messages.size
       xml.tag! "sent", :count => user.sent_messages.size
     end
+    xml.tag! "email", user.email if scope_enabled?(:read_email)
   end
 end

config/locales/en.yml

@@ -2342,6 +2342,7 @@ en:
       read_gpx: Read private GPS traces
       write_gpx: Upload GPS traces
       write_notes: Modify notes
+      read_email: Read user email address
   oauth_clients:
     new:
       title: "Register a new application"

lib/oauth.rb

@@ -1,6 +1,6 @@
 module Oauth
   SCOPES = %w[read_prefs write_prefs write_diary write_api read_gpx write_gpx write_notes].freeze
-  PRIVILEGED_SCOPES = %w[].freeze
+  PRIVILEGED_SCOPES = %w[read_email].freeze
 
   class Scope
     attr_reader :name