FIX: Improve error messages if user cannot send PM emails (#12547)

app/assets/javascripts/discourse/app/templates/components/composer-user-selector.hbs

@@ -7,7 +7,7 @@
     topicId=topicId
     filterPlaceholder="composer.users_placeholder"
     includeMessageableGroups=true
-    allowEmails=true
+    allowEmails=currentUser.can_send_private_email_messages
     autoWrap=true
   )
 }}

config/locales/server.en.yml

@@ -568,6 +568,7 @@ en:
               cant_send_pm: "Sorry, you cannot send a personal message to that user."
               no_user_selected: "You must select a valid user."
               reply_by_email_disabled: "Reply by email has been disabled."
+              send_to_email_disabled: "Sorry, you cannot send personal messages to email."
               target_user_not_found: "One of the users you are sending this message to could not be found."
               unable_to_update: "There was an error updating that topic."
               unable_to_tag: "There was an error tagging the topic."

lib/topic_creator.rb

@@ -193,7 +193,7 @@ class TopicCreator
     end
 
     if @opts[:target_emails].present? && !@guardian.can_send_private_messages_to_email? then
-      rollback_with!(topic, :reply_by_email_disabled)
+      rollback_with!(topic, :send_to_email_disabled)
     end
 
     add_users(topic, @opts[:target_usernames])

spec/components/topic_creator_spec.rb

@@ -245,6 +245,17 @@ describe TopicCreator do
           end.to raise_error(ActiveRecord::Rollback)
         end
       end
+
+      context 'to emails' do
+        it 'works for staff' do
+          expect(TopicCreator.create(admin, Guardian.new(admin), pm_valid_attrs.merge(target_emails: 'test@example.com'))).to be_valid
+        end
+
+        it 'does not work for non-staff' do
+          user.update!(trust_level: TrustLevel[4])
+          expect { TopicCreator.create(user, Guardian.new(user), pm_valid_attrs.merge(target_emails: 'test@example.com')) }.to raise_error(ActiveRecord::Rollback)
+        end
+      end
     end
 
     context 'setting timestamps' do