FIX: Handle actor not having preferences in UserCommScreener (#17790)

Followup to d66115d918

* Makes sure the `actor_preferences` all initialize with an empty array instead of nil if there are no preferences e.g. the actor is not ignoring anyone
* If the actor has disabled all PMs make `actor_disallowing_pms?` always return true

lib/user_comm_screener.rb

@@ -172,6 +172,7 @@ class UserCommScreener
 
   def actor_disallowing_pms?(user_id)
     validate_user_id!(user_id)
+    return true if actor_disallowing_all_pms?
     return false if !acting_user.user_option.enable_allowed_pm_users
     actor_preferences[:disallowed_pms_from].include?(user_id)
   end
@@ -244,10 +245,16 @@ class UserCommScreener
         hash[pref.preference_type] << pref.target_user_id
         hash
       end
+      disallowed_pms_from = \
+        if acting_user.user_option.enable_allowed_pm_users
+          (user_ids_by_preference_type["disallowed_pm"] || [])
+        else
+          []
+        end
       {
-        muting: user_ids_by_preference_type["muted"],
-        ignoring: user_ids_by_preference_type["ignored"],
-        disallowed_pms_from: user_ids_by_preference_type["disallowed_pm"]
+        muting: user_ids_by_preference_type["muted"] || [],
+        ignoring: user_ids_by_preference_type["ignored"] || [],
+        disallowed_pms_from: disallowed_pms_from
       }
     end
   end

spec/lib/user_comm_screener_spec.rb

@@ -195,6 +195,23 @@ RSpec.describe UserCommScreener do
           target_user1.id, target_user2.id, target_user3.id, target_user5.id
         ])
       end
+
+      it "does not include users the actor is disallowing PMs from if they have not set enable_allowed_pm_users" do
+        expect(subject.actor_preventing_communication).to match_array([
+          target_user1.id, target_user2.id
+        ])
+      end
+
+      describe "when the actor has no preferences" do
+        before do
+          muted_user.destroy
+          ignored_user.destroy
+        end
+
+        it "returns an empty array and does not error" do
+          expect(subject.actor_preventing_communication).to match_array([])
+        end
+      end
     end
 
     describe "#actor_allowing_communication" do
@@ -202,6 +219,19 @@ RSpec.describe UserCommScreener do
         acting_user.user_option.update!(enable_allowed_pm_users: true)
         expect(subject.actor_allowing_communication).to match_array([target_user4.id])
       end
+
+      describe "when the actor has no preferences" do
+        before do
+          muted_user.destroy
+          ignored_user.destroy
+        end
+
+        it "returns an array of the target users and does not error" do
+          expect(subject.actor_allowing_communication).to match_array([
+            target_user1.id, target_user2.id, target_user3.id, target_user4.id, target_user5.id
+          ])
+        end
+      end
     end
 
     describe "#actor_ignoring?" do
@@ -233,6 +263,12 @@ RSpec.describe UserCommScreener do
         expect(subject.actor_disallowing_pms?(target_user1.id)).to eq(false)
       end
 
+      it "returns true if the actor has disallowed all PMs" do
+        acting_user.user_option.update!(allow_private_messages: false)
+        expect(subject.actor_disallowing_pms?(target_user3.id)).to eq(true)
+        expect(subject.actor_disallowing_pms?(target_user1.id)).to eq(true)
+      end
+
       it "raises a NotFound error if the user_id passed in is not part of the target users" do
         expect { subject.actor_disallowing_pms?(other_user.id) }.to raise_error(Discourse::NotFound)
       end