FIX: stop memoize PostActionTypes (#28005)

Memoizing all_flags on PostActionType was a mistake. This commit brings back the cache on the serialize level.

app/models/post_action_type.rb

@@ -1,8 +1,16 @@
 # frozen_string_literal: true
 
 class PostActionType < ActiveRecord::Base
+  after_save :expire_cache
+  after_destroy :expire_cache
+
   include AnonCacheInvalidator
 
+  def expire_cache
+    ApplicationSerializer.expire_cache_fragment!(/\Apost_action_types_/)
+    ApplicationSerializer.expire_cache_fragment!(/\Apost_action_flag_types_/)
+  end
+
   class << self
     attr_reader :flag_settings
 
@@ -13,7 +21,6 @@ class PostActionType < ActiveRecord::Base
     def replace_flag_settings(settings)
       Discourse.deprecate("Flags should not be replaced. Insert custom flags as database records.")
       @flag_settings = settings || FlagSettings.new
-      @all_flags = nil
     end
 
     def types
@@ -23,10 +30,15 @@ class PostActionType < ActiveRecord::Base
       Enum.new(like: 2).merge(flag_types)
     end
 
+    def expire_cache
+      Discourse.redis.keys("post_action_types_*").each { |key| Discourse.redis.del(key) }
+      Discourse.redis.keys("post_action_flag_types_*").each { |key| Discourse.redis.del(key) }
+    end
+
     def reload_types
-      @all_flags = nil
       @flag_settings = FlagSettings.new
       ReviewableScore.reload_types
+      PostActionType.new.expire_cache
     end
 
     def overridden_by_plugin_or_skipped_db?
@@ -34,7 +46,7 @@ class PostActionType < ActiveRecord::Base
     end
 
     def all_flags
-      @all_flags ||= Flag.unscoped.order(:position).all
+      Flag.unscoped.order(:position).all
     end
 
     def auto_action_flag_types

app/serializers/post_serializer.rb

@@ -290,7 +290,10 @@ class PostSerializer < BasicPostSerializer
     result = []
     can_see_post = scope.can_see_post?(object)
 
-    PostActionType.types.each do |sym, id|
+    public_flag_types =
+      (@topic_view.present? ? @topic_view.public_flag_types : PostActionType.public_types)
+
+    (@topic_view.present? ? @topic_view.flag_types : PostActionType.types).each do |sym, id|
       count_col = "#{sym}_count".to_sym
 
       count = object.public_send(count_col) if object.respond_to?(count_col)
@@ -301,6 +304,22 @@ class PostSerializer < BasicPostSerializer
            sym,
            opts: {
              taken_actions: actions,
+             notify_flag_types:
+               (
+                 if @topic_view.present?
+                   @topic_view.notify_flag_types
+                 else
+                   PostActionType.notify_flag_types
+                 end
+               ),
+             additional_message_types:
+               (
+                 if @topic_view.present?
+                   @topic_view.additional_message_types
+                 else
+                   PostActionType.additional_message_types
+                 end
+               ),
            },
            can_see_post: can_see_post,
          )
@@ -327,7 +346,7 @@ class PostSerializer < BasicPostSerializer
       end
 
       # only show public data
-      unless scope.is_staff? || PostActionType.public_types.values.include?(id)
+      unless scope.is_staff? || public_flag_types.values.include?(id)
         summary[:count] = summary[:acted] ? 1 : 0
       end
 

app/serializers/site_serializer.rb

@@ -111,13 +111,17 @@ class SiteSerializer < ApplicationSerializer
   end
 
   def post_action_types
-    types = ordered_flags(PostActionType.types.values)
-    ActiveModel::ArraySerializer.new(types).as_json
+    cache_fragment("post_action_types_#{I18n.locale}") do
+      types = ordered_flags(PostActionType.types.values)
+      ActiveModel::ArraySerializer.new(types).as_json
+    end
   end
 
   def topic_flag_types
-    types = ordered_flags(PostActionType.topic_flag_types.values)
-    ActiveModel::ArraySerializer.new(types, each_serializer: TopicFlagTypeSerializer).as_json
+    cache_fragment("post_action_flag_types_#{I18n.locale}") do
+      types = ordered_flags(PostActionType.topic_flag_types.values)
+      ActiveModel::ArraySerializer.new(types, each_serializer: TopicFlagTypeSerializer).as_json
+    end
   end
 
   def default_archetype

lib/guardian/post_guardian.rb

@@ -38,8 +38,12 @@ module PostGuardian
 
     taken = opts[:taken_actions].try(:keys).to_a
     is_flag =
-      PostActionType.notify_flag_types[action_key] ||
-        PostActionType.additional_message_types[action_key]
+      if (opts[:notify_flag_types] && opts[:additional_message_types])
+        opts[:notify_flag_types][action_key] || opts[:additional_message_types][action_key]
+      else
+        PostActionType.notify_flag_types[action_key] ||
+          PostActionType.additional_message_types[action_key]
+      end
     already_taken_this_action = taken.any? && taken.include?(PostActionType.types[action_key])
     already_did_flagging = taken.any? && (taken & PostActionType.notify_flag_types.values).any?
 

lib/topic_view.rb

@@ -623,6 +623,22 @@ class TopicView
     @pm_params ||= TopicQuery.new(@user).get_pm_params(topic)
   end
 
+  def flag_types
+    @flag_types ||= PostActionType.types
+  end
+
+  def public_flag_types
+    @public_flag_types ||= PostActionType.public_types
+  end
+
+  def notify_flag_types
+    @notify_flag_types ||= PostActionType.notify_flag_types
+  end
+
+  def additional_message_types
+    @additional_message_types ||= PostActionType.additional_message_types
+  end
+
   def suggested_topics
     if @include_suggested
       @suggested_topics ||=

spec/models/post_action_type_spec.rb

@@ -1,6 +1,24 @@
 # frozen_string_literal: true
 
 RSpec.describe PostActionType do
+  describe "Callbacks" do
+    describe "#expiry_cache" do
+      it "should clear the cache on save" do
+        cache = ApplicationSerializer.fragment_cache
+
+        cache["post_action_types_#{I18n.locale}"] = "test"
+        cache["post_action_flag_types_#{I18n.locale}"] = "test2"
+
+        PostActionType.new(name_key: "some_key").save!
+
+        expect(cache["post_action_types_#{I18n.locale}"]).to eq(nil)
+        expect(cache["post_action_flag_types_#{I18n.locale}"]).to eq(nil)
+      ensure
+        ApplicationSerializer.fragment_cache.clear
+      end
+    end
+  end
+
   describe "#types" do
     context "when verifying enum sequence" do
       before { @types = PostActionType.types }