FIX: discobot fails when max_emojis_in_title=0 (#5710)

* If discobot is enabled but max_emojis_in_title==0,
  try to strip emoji from the title when creating a new post

plugins/discourse-narrative-bot/lib/discourse_narrative_bot/new_user_narrative.rb

@@ -182,8 +182,13 @@ module DiscourseNarrativeBot
       #{instance_eval(&@next_instructions)}
       RAW
 
+      title = I18n.t("#{I18N_KEY}.hello.title", title: SiteSetting.title)
+      if SiteSetting.max_emojis_in_title == 0
+        title = title.gsub(/:([\w\-+]+(?::t\d)?):/, '').strip
+      end
+
       opts = {
-        title: I18n.t("#{I18N_KEY}.hello.title", title: SiteSetting.title),
+        title: title,
         target_usernames: @user.username,
         archetype: Archetype.private_message,
         subtype: TopicSubtype.system_message,

plugins/discourse-narrative-bot/spec/user_spec.rb

@@ -32,6 +32,21 @@ describe User do
         end
       end
 
+      context 'with title emoji disabled' do
+        before do
+          SiteSetting.disable_discourse_narrative_bot_welcome_post = false
+          SiteSetting.max_emojis_in_title = 0
+        end
+
+        it 'initiates the bot' do
+          expect { user }.to change { Topic.count }.by(1)
+
+          expect(Topic.last.title).to eq(I18n.t(
+            'discourse_narrative_bot.new_user_narrative.hello.title'
+          ).gsub(/:robot:/, '').strip)
+        end
+      end
+
       context 'enabled' do
         before do
           SiteSetting.disable_discourse_narrative_bot_welcome_post = false