New site settings to enable/disable the possibility of editing user's nickname or email address

app/assets/javascripts/discourse/templates/user/preferences.js.handlebars

@@ -27,7 +27,9 @@
     <label class="control-label">{{i18n user.email.title}}</label>
     <div class="controls">
       <span class='static'>{{email}}</span>
-      {{#linkTo "preferences.email" class="btn pad-left"}}<i class="icon-pencil"></i>{{/linkTo}}
+      {{#if can_edit_email}}
+        {{#linkTo "preferences.email" class="btn pad-left"}}<i class="icon-pencil"></i>{{/linkTo}}
+      {{/if}}
     </div>
     <div class='instructions'>
       {{i18n user.email.instructions}}

app/controllers/users_controller.rb

@@ -205,7 +205,7 @@ class UsersController < ApplicationController
   def change_email
     params.require(:email)
     user = fetch_user_from_params
-    guardian.ensure_can_edit!(user)
+    guardian.ensure_can_edit_email!(user)
     lower_email = Email.downcase(params[:email]).strip
 
     # Raise an error if the email is already in use

app/models/site_setting.rb

@@ -251,6 +251,7 @@ class SiteSetting < ActiveRecord::Base
   setting(:delete_all_posts_max, 10)
 
   setting(:username_change_period, 3) # days
+  setting(:email_editable, true)
 
   client_setting(:allow_uploaded_avatars, true)
   client_setting(:allow_animated_avatars, false)

app/serializers/user_serializer.rb

@@ -10,6 +10,7 @@ class UserSerializer < BasicUserSerializer
              :website,
              :can_edit,
              :can_edit_username,
+             :can_edit_email,
              :stats,
              :can_send_private_message_to_user,
              :bio_excerpt,
@@ -78,6 +79,10 @@ class UserSerializer < BasicUserSerializer
     scope.can_edit_username?(object)
   end
 
+  def can_edit_email
+    scope.can_edit_email?(object)
+  end
+
   def stats
     UserAction.stats(object.id, scope)
   end

config/locales/server.en.yml

@@ -684,7 +684,8 @@ en:
     relative_date_duration: "Number of days after posting where post dates will be shown as relative instead of absolute. Examples: relative date: 7d, absolute date: 20 Feb"
     delete_user_max_age: "The maximum age of a user, in days, which can be deleted by an admin."
     delete_all_posts_max: "The maximum number of posts that can be deleted at once with the Delete All Posts button. If a user has more than this many posts, the posts cannot all be deleted at once and the user can't be deleted."
-    username_change_period: "The number of days after registration that accounts can change their username."
+    username_change_period: "The number of days after registration that accounts can change their username (0 to disallow username change)."
+    email_editable: "Allow users to change their e-mail address after registration."
 
     allow_uploaded_avatars: "Allow users to upload their custom avatars"
     allow_animated_avatars: "Allow users to use animated gif for avatars. WARNING: it is highly recommended to run the avatars:regenerate rake task after changing that setting."

lib/guardian.rb

@@ -285,7 +285,15 @@ class Guardian
   end
 
   def can_edit_username?(user)
-    is_staff? || (is_me?(user) && (user.post_count == 0 || user.created_at > SiteSetting.username_change_period.days.ago))
+    return true if is_staff?
+    return false if SiteSetting.username_change_period <= 0
+    is_me?(user) && (user.post_count == 0 || user.created_at > SiteSetting.username_change_period.days.ago)
+  end
+
+  def can_edit_email?(user)
+    return true if is_staff?
+    return false unless SiteSetting.email_editable?
+    can_edit?(user)
   end
 
   # Deleting Methods

spec/components/guardian_spec.rb

@@ -1195,6 +1195,72 @@ describe Guardian do
         end
       end
     end
+
+    context 'when editing is disabled in preferences' do
+      before do
+        SiteSetting.stubs(:username_change_period).returns(0)
+      end
+
+      include_examples "staff can always change usernames"
+
+      it "is false for the user to change his own username" do
+        Guardian.new(user).can_edit_username?(user).should be_false
+      end
+    end
+  end
+
+  describe "can_edit_email?" do
+    context 'when allowed in settings' do
+      before do
+        SiteSetting.stubs(:email_editable?).returns(true)
+      end
+
+      it "is false when not logged in" do
+        Guardian.new(nil).can_edit_email?(build(:user, created_at: 1.minute.ago)).should be_false
+      end
+
+      it "is false for regular users to edit another user's email" do
+        Guardian.new(build(:user)).can_edit_email?(build(:user, created_at: 1.minute.ago)).should be_false
+      end
+
+      it "is true for a regular user to edit his own email" do
+        Guardian.new(user).can_edit_email?(user).should be_true
+      end
+
+      it "is true for moderators" do
+        Guardian.new(moderator).can_edit_email?(user).should be_true
+      end
+
+      it "is true for admins" do
+        Guardian.new(admin).can_edit_email?(user).should be_true
+      end
+    end
+
+    context 'when not allowed in settings' do
+      before do
+        SiteSetting.stubs(:email_editable?).returns(false)
+      end
+
+      it "is false when not logged in" do
+        Guardian.new(nil).can_edit_email?(build(:user, created_at: 1.minute.ago)).should be_false
+      end
+
+      it "is false for regular users to edit another user's email" do
+        Guardian.new(build(:user)).can_edit_email?(build(:user, created_at: 1.minute.ago)).should be_false
+      end
+
+      it "is false for a regular user to edit his own email" do
+        Guardian.new(user).can_edit_email?(user).should be_false
+      end
+
+      it "is true for admins" do
+        Guardian.new(admin).can_edit_email?(user).should be_true
+      end
+
+      it "is true for moderators" do
+        Guardian.new(moderator).can_edit_email?(user).should be_true
+      end
+    end
   end
 
 end

spec/controllers/users_controller_spec.rb

@@ -181,8 +181,8 @@ describe UsersController do
         lambda { xhr :put, :change_email, username: user.username }.should raise_error(ActionController::ParameterMissing)
       end
 
-      it "raises an error if you can't edit the user" do
-        Guardian.any_instance.expects(:can_edit?).with(user).returns(false)
+      it "raises an error if you can't edit the user's email" do
+        Guardian.any_instance.expects(:can_edit_email?).with(user).returns(false)
         xhr :put, :change_email, username: user.username, email: new_email
         response.should be_forbidden
       end