FIX: Look up all channel hashtags (#25617)

plugins/chat/lib/chat/channel_fetcher.rb

@@ -80,7 +80,6 @@ module Chat
         .where(chatable_type: Chat::Channel.public_channel_chatable_types)
         .where("chat_channels.id IN (#{allowed_channel_ids})")
         .where("chat_channels.slug IN (:slugs)", slugs: slugs)
-        .limit(1)
     end
 
     def self.secured_public_channel_search(guardian, options = {})

plugins/chat/spec/services/hashtag_autocomplete_service_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+RSpec.describe HashtagAutocompleteService do
+  subject(:service) { described_class.new(guardian) }
+
+  fab!(:channel1) { Fabricate(:chat_channel, name: "Music Lounge", slug: "music") }
+  fab!(:channel2) { Fabricate(:chat_channel, name: "Random", slug: "random") }
+
+  fab!(:admin)
+  let(:guardian) { Guardian.new(admin) }
+
+  describe ".enabled_data_sources" do
+    it "only returns data sources that are enabled" do
+      expect(HashtagAutocompleteService.enabled_data_sources).to include(
+        Chat::ChannelHashtagDataSource,
+      )
+    end
+  end
+
+  describe "#lookup" do
+    it "returns hashtags for channels" do
+      result = service.lookup(%w[music::channel random::channel], ["channel"])
+      expect(result[:channel].map(&:slug)).to contain_exactly("music", "random")
+    end
+  end
+end