lib/pleroma/hashtag.ex

@@ -121,10 +121,13 @@ def get_followers(%Hashtag{id: hashtag_id}) do
     |> Repo.all()
   end
 
-  def get_recipients_for_activity(%Pleroma.Activity{object: %{hashtags: tags}}) do
+  def get_recipients_for_activity(%Pleroma.Activity{object: %{hashtags: tags}})
+      when is_list(tags) do
     tags
     |> Enum.map(&get_followers/1)
     |> List.flatten()
     |> Enum.uniq()
   end
+
+  def get_recipients_for_activity(_activity), do: []
 end

test/pleroma/web/streamer_test.exs

@@ -410,6 +410,36 @@ test "it streams own edits in the 'user' stream", %{user: user, token: oauth_tok
       assert_receive {:render_with_user, _, "status_update.json", ^create, ^stream}
       refute Streamer.filtered_by_user?(user, edited)
     end
+
+    test "it streams posts containing followed hashtags on the 'user' stream", %{
+      user: user,
+      token: oauth_token
+    } do
+      hashtag = insert(:hashtag, %{name: "tenshi"})
+      other_user = insert(:user)
+      {:ok, user} = User.follow_hashtag(user, hashtag)
+
+      Streamer.get_topic_and_add_socket("user", user, oauth_token)
+      {:ok, activity} = CommonAPI.post(other_user, %{status: "hey #tenshi"})
+
+      assert_receive {:render_with_user, _, "update.json", ^activity, _}
+    end
+
+    test "should not stream private posts containing followed hashtags on the 'user' stream", %{
+      user: user,
+      token: oauth_token
+    } do
+      hashtag = insert(:hashtag, %{name: "tenshi"})
+      other_user = insert(:user)
+      {:ok, user} = User.follow_hashtag(user, hashtag)
+
+      Streamer.get_topic_and_add_socket("user", user, oauth_token)
+
+      {:ok, activity} =
+        CommonAPI.post(other_user, %{status: "hey #tenshi", visibility: "private"})
+
+      refute_receive {:render_with_user, _, "update.json", ^activity, _}
+    end
   end
 
   describe "public streams" do