Change discoverable accounts to only allow followers to feature them if they are locked (#38672)

app/models/account.rb

@@ -473,7 +473,7 @@ class Account < ApplicationRecord
   end
 
   def featureable_by?(other_account)
-    return discoverable? if local?
+    return discoverable? && (!locked? || followed_by?(other_account)) if local?
 
     feature_policy_for_account(other_account).in?(%i(automatic manual))
   end

app/models/concerns/account/interaction_policy_concern.rb

@@ -64,6 +64,6 @@ module Account::InteractionPolicyConcern
   def local_feature_policy(kind)
     return [] if kind == :manual || !discoverable?
 
-    [:public]
+    [locked? ? :followers : :public]
   end
 end

app/serializers/activitypub/actor_serializer.rb

@@ -176,7 +176,15 @@ class ActivityPub::ActorSerializer < ActivityPub::Serializer
   end
 
   def interaction_policy
-    uri = object.discoverable? ? ActivityPub::TagManager::COLLECTIONS[:public] : ActivityPub::TagManager.instance.uri_for(object)
+    uri = begin
+      if !object.discoverable?
+        ActivityPub::TagManager.instance.uri_for(object)
+      elsif object.locked?
+        ActivityPub::TagManager.instance.followers_uri_for(object)
+      else
+        ActivityPub::TagManager::COLLECTIONS[:public]
+      end
+    end
 
     {
       canFeature: {

spec/models/account_spec.rb

@@ -772,19 +772,42 @@ RSpec.describe Account do
   end
 
   describe '#featureable_by?' do
-    subject { Fabricate.build(:account, domain: (local ? nil : 'example.com'), discoverable:, feature_approval_policy:) }
+    subject { Fabricate.build(:account, domain: (local ? nil : 'example.com'), discoverable:, locked:, feature_approval_policy:) }
 
+    let(:locked) { false }
     let(:local_account) { Fabricate(:account) }
 
     context 'when account is local' do
       let(:local) { true }
-      let(:feature_approval_policy) { nil }
+      let(:feature_approval_policy) { 0 }
 
       context 'when account is discoverable' do
         let(:discoverable) { true }
 
-        it 'returns `true`' do
-          expect(subject.featureable_by?(local_account)).to be true
+        context 'when the account is not locked' do
+          let(:locked) { false }
+
+          it 'returns `true`' do
+            expect(subject.featureable_by?(local_account)).to be true
+          end
+        end
+
+        context 'when the account is locked' do
+          let(:locked) { true }
+
+          it 'returns `false`' do
+            expect(subject.featureable_by?(local_account)).to be false
+          end
+
+          context 'when the other account is a follower' do
+            before do
+              local_account.follow!(subject)
+            end
+
+            it 'returns `true`' do
+              expect(subject.featureable_by?(local_account)).to be true
+            end
+          end
         end
       end
 

spec/serializers/activitypub/actor_serializer_spec.rb

@@ -56,6 +56,18 @@ RSpec.describe ActivityPub::ActorSerializer do
             },
           })
         end
+
+        context 'when actor is locked' do
+          let(:record) { Fabricate(:account, locked: true) }
+
+          it 'includes an automatic policy allowing followers' do
+            expect(subject).to include('interactionPolicy' => {
+              'canFeature' => {
+                'automaticApproval' => [ActivityPub::TagManager.instance.followers_uri_for(record)],
+              },
+            })
+          end
+        end
       end
 
       context 'when actor is not discoverable' do

spec/serializers/rest/account_serializer_spec.rb

@@ -93,6 +93,18 @@ RSpec.describe REST::AccountSerializer do
               'current_user' => 'automatic',
             })
           end
+
+          context 'when account is locked' do
+            let(:account) { Fabricate(:account, locked: true) }
+
+            it 'includes a policy that allows featuring for followers' do
+              expect(subject['feature_approval']).to include({
+                'automatic' => ['followers'],
+                'manual' => [],
+                'current_user' => 'automatic',
+              })
+            end
+          end
         end
 
         context 'when account is not discoverable' do