FIX: do not allow new email to be duplicate

FIX: return proper error message when email already exists

app/assets/javascripts/discourse/controllers/preferences/email.js.es6

@@ -9,10 +9,10 @@ export default Ember.Controller.extend({
 
   newEmailEmpty: Em.computed.empty('newEmail'),
   saveDisabled: Em.computed.or('saving', 'newEmailEmpty', 'taken', 'unchanged'),
-  unchanged: propertyEqual('newEmailLower', 'email'),
+  unchanged: propertyEqual('newEmailLower', 'currentUser.email'),
 
   newEmailLower: function() {
-    return this.get('newEmail').toLowerCase();
+    return this.get('newEmail').toLowerCase().trim();
   }.property('newEmail'),
 
   saveButtonText: function() {

app/controllers/users_controller.rb

@@ -483,9 +483,7 @@ class UsersController < ApplicationController
     return render_json_error(user.errors.full_messages) if user.errors[:email].present?
 
     # Raise an error if the email is already in use
-    if User.find_by_email(lower_email)
-      raise Discourse::InvalidParameters.new(:email)
-    end
+    return render_json_error(I18n.t('change_email.error')) if User.find_by_email(lower_email)
 
     email_token = user.email_tokens.create(email: lower_email)
     Jobs.enqueue(

spec/controllers/users_controller_spec.rb

@@ -242,11 +242,13 @@ describe UsersController do
       context 'when the new email address is taken' do
         let!(:other_user) { Fabricate(:coding_horror) }
         it 'raises an error' do
-          expect { xhr :put, :change_email, username: user.username, email: other_user.email }.to raise_error(Discourse::InvalidParameters)
+          xhr :put, :change_email, username: user.username, email: other_user.email
+          expect(response).to_not be_success
         end
 
         it 'raises an error if there is whitespace too' do
-          expect { xhr :put, :change_email, username: user.username, email: other_user.email + ' ' }.to raise_error(Discourse::InvalidParameters)
+          xhr :put, :change_email, username: user.username, email: other_user.email + ' '
+          expect(response).to_not be_success
         end
       end
 
@@ -254,7 +256,8 @@ describe UsersController do
         let!(:other_user) { Fabricate(:user, email: 'case.insensitive@gmail.com')}
 
         it 'raises an error' do
-          expect { xhr :put, :change_email, username: user.username, email: other_user.email.upcase }.to raise_error(Discourse::InvalidParameters)
+          xhr :put, :change_email, username: user.username, email: other_user.email.upcase
+          expect(response).to_not be_success
         end
       end