FEATURE: Support designating multiple groups as mods on category (#28655)

Currently, categories support designating only 1 group as a moderation group on the category. This commit removes the one group limitation and makes it possible to designate multiple groups as mods on a category.

Internal topic: t/124648.

app/assets/javascripts/discourse/app/components/edit-category-settings.hbs

@@ -120,11 +120,10 @@
   {{#if this.siteSettings.enable_category_group_moderation}}
     <section class="field reviewable-by-group">
       <label>{{i18n "category.reviewable_by_group"}}</label>
-      <GroupSelector
+      <GroupChooser
-        @groupFinder={{this.groupFinder}}
+        @content={{this.site.groups}}
-        @single="true"
+        @value={{this.category.moderating_group_ids}}
-        @groupNames={{this.category.reviewable_by_group_name}}
+        @onChange={{this.onCategoryModeratingGroupsChange}}
-        @placeholderKey="category.review_group_name"
       />
     </section>
   {{/if}}

app/assets/javascripts/discourse/app/components/edit-category-settings.js

@@ -3,7 +3,6 @@ import { and, empty } from "@ember/object/computed";
 import { buildCategoryPanel } from "discourse/components/edit-category-panel";
 import { setting } from "discourse/lib/computed";
 import { SEARCH_PRIORITIES } from "discourse/lib/constants";
-import Group from "discourse/models/group";
 import discourseComputed from "discourse-common/utils/decorators";
 import I18n from "discourse-i18n";
 
@@ -50,10 +49,6 @@ export default class EditCategorySettings extends buildCategoryPanel(
     ];
   }
 
-  groupFinder(term) {
-    return Group.findAll({ term, ignore_automatic: true });
-  }
-
   @discourseComputed
   availableViews() {
     return [
@@ -146,4 +141,9 @@ export default class EditCategorySettings extends buildCategoryPanel(
     let seconds = minutes ? minutes * 60 : null;
     this.set("category.default_slow_mode_seconds", seconds);
   }
+
+  @action
+  onCategoryModeratingGroupsChange(groupIds) {
+    this.set("category.moderating_group_ids", groupIds);
+  }
 }

app/assets/javascripts/discourse/app/models/category.js

@@ -761,7 +761,7 @@ export default class Category extends RestModel {
           "navigate_to_first_post_after_read"
         ),
         search_priority: this.search_priority,
-        reviewable_by_group_name: this.reviewable_by_group_name,
+        moderating_group_ids: this.moderating_group_ids,
         read_only_banner: this.read_only_banner,
         default_list_filter: this.default_list_filter,
       }),

app/assets/javascripts/discourse/app/models/topic.js

@@ -751,8 +751,8 @@ export default class Topic extends RestModel {
         if (
           opts.force_destroy ||
           (!deleted_by.staff &&
-            !deleted_by.groups.some(
+            !deleted_by.groups.some((group) =>
-              (group) => group.name === this.category?.reviewable_by_group_name
+              this.category?.moderating_group_ids?.includes(group.id)
             ) &&
             !deleted_by.can_delete_all_posts_and_topics)
         ) {

app/controllers/categories_controller.rb

@@ -578,10 +578,9 @@ class CategoriesController < ApplicationController
           ]
         end
 
+        conditional_param_keys = []
         if SiteSetting.enable_category_group_moderation?
-          params[:reviewable_by_group_id] = Group.where(
+          conditional_param_keys << { moderating_group_ids: [] }
-            name: params[:reviewable_by_group_name],
-          ).pick(:id) if params[:reviewable_by_group_name]
         end
 
         result =
@@ -621,7 +620,7 @@ class CategoriesController < ApplicationController
             :allow_global_tags,
             :read_only_banner,
             :default_list_filter,
-            :reviewable_by_group_id,
+            *conditional_param_keys,
             category_setting_attributes: %i[
               auto_bump_cooldown_days
               num_auto_bump_daily

app/controllers/reviewable_claimed_topics_controller.rb

@@ -36,9 +36,8 @@ class ReviewableClaimedTopicsController < ApplicationController
   def notify_users(topic, claimed_by)
     group_ids = Set.new([Group::AUTO_GROUPS[:staff]])
 
-    if SiteSetting.enable_category_group_moderation? &&
+    if SiteSetting.enable_category_group_moderation? && topic.category
-         group_id = topic.category&.reviewable_by_group_id.presence
+      group_ids.merge(topic.category.moderating_group_ids)
-      group_ids.add(group_id)
     end
 
     if claimed_by.present?

app/jobs/regular/notify_reviewable.rb

@@ -20,23 +20,18 @@ class Jobs::NotifyReviewable < ::Jobs::Base
 
           all_updates[:admins][r.id] = payload
           all_updates[:moderators][r.id] = payload if r.reviewable_by_moderator?
-          all_updates[r.reviewable_by_group_id][r.id] = payload if r.reviewable_by_group_id
+
+          if SiteSetting.enable_category_group_moderation? && r.category.present?
+            r
+              .category
+              .moderating_groups
+              .pluck(:id)
+              .each { |group_id| all_updates[group_id][r.id] = payload }
+          end
         end
     end
 
     DistributedMutex.synchronize("notify_reviewable_job", validity: 120) do
-      counts = Hash.new(0)
-      Reviewable
-        .default_visible
-        .pending
-        .group(:reviewable_by_moderator, :reviewable_by_group_id)
-        .pluck(:reviewable_by_moderator, :reviewable_by_group_id, "count(*)")
-        .each do |reviewable_by_moderator, reviewable_by_group_id, count|
-          counts[:admins] += count
-          counts[:moderators] += count if reviewable_by_moderator
-          counts[reviewable_by_group_id] += count if reviewable_by_group_id
-        end
-
       notify_users(User.real.admins, all_updates[:admins])
 
       if reviewable.reviewable_by_moderator?
@@ -46,16 +41,21 @@ class Jobs::NotifyReviewable < ::Jobs::Base
         )
       end
 
-      if SiteSetting.enable_category_group_moderation? && (group = reviewable.reviewable_by_group)
+      if SiteSetting.enable_category_group_moderation? && reviewable.category.present?
-        users = group.users.includes(:group_users).where("users.id NOT IN (?)", @contacted)
+        users =
+          User
+            .includes(:group_users)
+            .joins(:group_users)
+            .joins(
+              "INNER JOIN category_moderation_groups ON category_moderation_groups.group_id = group_users.group_id",
+            )
+            .where("category_moderation_groups.category_id": reviewable.category.id)
+            .where("users.id NOT IN (?)", @contacted)
+            .distinct
 
         users.find_each do |user|
-          count = 0
           updates = {}
-          user.group_users.each do |gu|
+          user.group_users.each { |gu| updates.merge!(all_updates[gu.group_id]) }
-            updates.merge!(all_updates[gu.group_id])
-            count += counts[gu.group_id]
-          end
 
           notify_user(user, updates)
         end

app/models/about.rb

@@ -88,7 +88,7 @@ class About
     allowed_cats = Guardian.new(@user).allowed_category_ids
     return [] if allowed_cats.blank?
 
-    cats_with_mods = Category.where.not(reviewable_by_group_id: nil).pluck(:id)
+    cats_with_mods = Category.joins(:category_moderation_groups).distinct.pluck(:id)
 
     category_ids = cats_with_mods & allowed_cats
     return [] if category_ids.blank?
@@ -96,15 +96,32 @@ class About
     per_cat_limit = category_mods_limit / category_ids.size
     per_cat_limit = 1 if per_cat_limit < 1
 
-    results = DB.query(<<~SQL, category_ids: category_ids)
+    results = DB.query(<<~SQL, category_ids:)
-        SELECT c.id category_id
+      WITH moderator_users AS (
-             , (ARRAY_AGG(u.id ORDER BY u.last_seen_at DESC))[:#{per_cat_limit}] user_ids
+        SELECT
-          FROM categories c
+          cmg.category_id AS category_id,
-          JOIN group_users gu ON gu.group_id = c.reviewable_by_group_id
+          u.id AS user_id,
-          JOIN users u ON u.id = gu.user_id
+          u.last_seen_at,
-         WHERE c.id IN (:category_ids)
+          ROW_NUMBER() OVER (PARTITION BY cmg.category_id, u.id ORDER BY u.last_seen_at DESC) as rn
-      GROUP BY c.id
+        FROM category_moderation_groups cmg
-      ORDER BY c.position
+        INNER JOIN group_users gu
+          ON cmg.group_id = gu.group_id
+        INNER JOIN users u
+          ON gu.user_id = u.id
+        WHERE cmg.category_id IN (:category_ids)
+      )
+      SELECT id AS category_id, user_ids
+      FROM categories
+      INNER JOIN (
+        SELECT
+          category_id,
+          (ARRAY_AGG(user_id ORDER BY last_seen_at DESC))[:#{per_cat_limit}] AS user_ids
+        FROM moderator_users
+        WHERE rn = 1
+        GROUP BY category_id
+      ) X
+      ON X.category_id = id
+      ORDER BY position
     SQL
 
     cats = Category.where(id: results.map(&:category_id)).index_by(&:id)

app/models/category.rb

@@ -7,6 +7,7 @@ class Category < ActiveRecord::Base
     :suppress_from_latest, # TODO: Remove when 20240212034010_drop_deprecated_columns has been promoted to pre-deploy
     :required_tag_group_id, # TODO: Remove when 20240212034010_drop_deprecated_columns has been promoted to pre-deploy
     :min_tags_from_required_group, # TODO: Remove when 20240212034010_drop_deprecated_columns has been promoted to pre-deploy
+    :reviewable_by_group_id,
   ]
 
   include Searchable
@@ -37,7 +38,9 @@ class Category < ActiveRecord::Base
   has_many :featured_topics, through: :category_featured_topics, source: :topic
 
   has_many :category_groups, dependent: :destroy
+  has_many :category_moderation_groups, dependent: :destroy
   has_many :groups, through: :category_groups
+  has_many :moderating_groups, through: :category_moderation_groups, source: :group
   has_many :topic_timers, dependent: :destroy
   has_many :upload_references, as: :target, dependent: :destroy
 
@@ -110,7 +113,6 @@ class Category < ActiveRecord::Base
   after_save :reset_topic_ids_cache
   after_save :clear_subcategory_ids
   after_save :clear_url_cache
-  after_save :update_reviewables
   after_save :publish_discourse_stylesheet
   after_save :publish_category
 
@@ -163,8 +165,6 @@ class Category < ActiveRecord::Base
   has_many :category_form_templates, dependent: :destroy
   has_many :form_templates, through: :category_form_templates
 
-  belongs_to :reviewable_by_group, class_name: "Group"
-
   scope :latest, -> { order("topic_count DESC") }
 
   scope :secured,
@@ -1113,10 +1113,8 @@ class Category < ActiveRecord::Base
     )
   end
 
-  def update_reviewables
+  def moderating_group_ids
-    if should_update_reviewables?
+    category_moderation_groups.pluck(:group_id)
-      Reviewable.where(category_id: id).update_all(reviewable_by_group_id: reviewable_by_group_id)
-    end
   end
 
   def self.find_by_slug_path(slug_path)
@@ -1278,10 +1276,6 @@ class Category < ActiveRecord::Base
     self.build_category_setting if self.category_setting.blank?
   end
 
-  def should_update_reviewables?
-    SiteSetting.enable_category_group_moderation? && saved_change_to_reviewable_by_group_id?
-  end
-
   def check_permissions_compatibility(parent_permissions, child_permissions)
     parent_groups = parent_permissions.map(&:first)
 
@@ -1381,7 +1375,6 @@ end
 #  navigate_to_first_post_after_read         :boolean          default(FALSE), not null
 #  search_priority                           :integer          default(0)
 #  allow_global_tags                         :boolean          default(FALSE), not null
-#  reviewable_by_group_id                    :integer
 #  read_only_banner                          :string
 #  default_list_filter                       :string(20)       default("all")
 #  allow_unlimited_owner_edits_on_first_post :boolean          default(FALSE), not null

app/models/category_moderation_group.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class CategoryModerationGroup < ActiveRecord::Base
+  belongs_to :category
+  belongs_to :group
+end
+
+# == Schema Information
+#
+# Table name: category_moderation_groups
+#
+#  id          :bigint           not null, primary key
+#  category_id :integer
+#  group_id    :integer
+#  created_at  :datetime         not null
+#  updated_at  :datetime         not null
+#
+# Indexes
+#
+#  index_category_moderation_groups_on_category_id_and_group_id  (category_id,group_id) UNIQUE
+#

app/models/group.rb

@@ -16,6 +16,7 @@ class Group < ActiveRecord::Base
   self.preloaded_custom_field_names = Set.new
 
   has_many :category_groups, dependent: :destroy
+  has_many :category_moderation_groups, dependent: :destroy
   has_many :group_users, dependent: :destroy
   has_many :group_requests, dependent: :destroy
   has_many :group_mentions, dependent: :destroy
@@ -24,15 +25,11 @@ class Group < ActiveRecord::Base
   has_many :group_archived_messages, dependent: :destroy
 
   has_many :categories, through: :category_groups
+  has_many :moderation_categories, through: :category_moderation_groups, source: :category
   has_many :users, through: :group_users
   has_many :human_users, -> { human_users }, through: :group_users, source: :user
   has_many :requesters, through: :group_requests, source: :user
   has_many :group_histories, dependent: :destroy
-  has_many :category_reviews,
-           class_name: "Category",
-           foreign_key: :reviewable_by_group_id,
-           dependent: :nullify
-  has_many :reviewables, foreign_key: :reviewable_by_group_id, dependent: :nullify
   has_many :group_category_notification_defaults, dependent: :destroy
   has_many :group_tag_notification_defaults, dependent: :destroy
   has_many :associated_groups, through: :group_associated_groups, dependent: :destroy
@@ -81,10 +78,6 @@ class Group < ActiveRecord::Base
     Discourse.cache.delete("group_imap_mailboxes_#{self.id}")
   end
 
-  def remove_review_groups
-    Category.where(review_group_id: self.id).update_all(review_group_id: nil)
-  end
-
   validate :name_format_validator
   validates :name, presence: true
   validate :automatic_membership_email_domains_format_validator

app/models/reviewable.rb

@@ -7,6 +7,8 @@ class Reviewable < ActiveRecord::Base
     ReviewableUser: BasicReviewableUserSerializer,
   }
 
+  self.ignored_columns = [:reviewable_by_group_id]
+
   class UpdateConflict < StandardError
   end
 
@@ -17,13 +19,11 @@ class Reviewable < ActiveRecord::Base
     end
   end
 
-  before_save :apply_review_group
   attr_accessor :created_new
   validates_presence_of :type, :status, :created_by_id
   belongs_to :target, polymorphic: true
   belongs_to :created_by, class_name: "User"
   belongs_to :target_created_by, class_name: "User"
-  belongs_to :reviewable_by_group, class_name: "Group"
 
   # Optional, for filtering
   belongs_to :topic
@@ -264,15 +264,6 @@ class Reviewable < ActiveRecord::Base
     )
   end
 
-  def apply_review_group
-    unless SiteSetting.enable_category_group_moderation? && category.present? &&
-             category.reviewable_by_group_id
-      return
-    end
-
-    self.reviewable_by_group_id = category.reviewable_by_group_id
-  end
-
   def actions_for(guardian, args = nil)
     args ||= {}
 
@@ -408,14 +399,17 @@ class Reviewable < ActiveRecord::Base
     group_ids =
       SiteSetting.enable_category_group_moderation? ? user.group_users.pluck(:group_id) : []
 
-    result.where(
+    result
-      "(reviewables.reviewable_by_moderator AND :staff) OR (reviewables.reviewable_by_group_id IN (:group_ids))",
+      .left_joins(category: :category_moderation_groups)
-      staff: user.staff?,
+      .where(
-      group_ids: group_ids,
+        "(reviewables.reviewable_by_moderator AND :moderator) OR (category_moderation_groups.group_id IN (:group_ids))",
-    ).where(
+        moderator: user.moderator?,
-      "reviewables.category_id IS NULL OR reviewables.category_id IN (?)",
+        group_ids: group_ids,
-      Guardian.new(user).allowed_category_ids,
+      )
-    )
+      .where(
+        "reviewables.category_id IS NULL OR reviewables.category_id IN (?)",
+        Guardian.new(user).allowed_category_ids,
+      )
   end
 
   def self.pending_count(user)
@@ -768,7 +762,6 @@ end
 #  status                  :integer          default("pending"), not null
 #  created_by_id           :integer          not null
 #  reviewable_by_moderator :boolean          default(FALSE), not null
-#  reviewable_by_group_id  :integer
 #  category_id             :integer
 #  topic_id                :integer
 #  score                   :float            default(0.0), not null

app/models/reviewable_flagged_post.rb

@@ -337,9 +337,16 @@ class ReviewableFlaggedPost < Reviewable
 
     user_ids = User.staff.pluck(:id)
 
-    if SiteSetting.enable_category_group_moderation? &&
+    if SiteSetting.enable_category_group_moderation? && topic.category
-         group_id = topic.category&.reviewable_by_group_id.presence
+      user_ids.concat(
-      user_ids.concat(GroupUser.where(group_id: group_id).pluck(:user_id))
+        GroupUser
+          .joins(
+            "INNER JOIN category_moderation_groups ON category_moderation_groups.group_id = group_users.group_id",
+          )
+          .where("category_moderation_groups.category_id": topic.category.id)
+          .distinct
+          .pluck(:user_id),
+      )
       user_ids.uniq!
     end
 
@@ -388,7 +395,6 @@ end
 #  status                  :integer          default("pending"), not null
 #  created_by_id           :integer          not null
 #  reviewable_by_moderator :boolean          default(FALSE), not null
-#  reviewable_by_group_id  :integer
 #  category_id             :integer
 #  topic_id                :integer
 #  score                   :float            default(0.0), not null

app/models/reviewable_post.rb

@@ -141,7 +141,6 @@ end
 #  status                  :integer          default("pending"), not null
 #  created_by_id           :integer          not null
 #  reviewable_by_moderator :boolean          default(FALSE), not null
-#  reviewable_by_group_id  :integer
 #  category_id             :integer
 #  topic_id                :integer
 #  score                   :float            default(0.0), not null

app/models/reviewable_queued_post.rb

@@ -241,7 +241,6 @@ end
 #  status                  :integer          default("pending"), not null
 #  created_by_id           :integer          not null
 #  reviewable_by_moderator :boolean          default(FALSE), not null
-#  reviewable_by_group_id  :integer
 #  category_id             :integer
 #  topic_id                :integer
 #  score                   :float            default(0.0), not null

app/models/reviewable_user.rb

@@ -105,7 +105,6 @@ end
 #  status                  :integer          default("pending"), not null
 #  created_by_id           :integer          not null
 #  reviewable_by_moderator :boolean          default(FALSE), not null
-#  reviewable_by_group_id  :integer
 #  category_id             :integer
 #  topic_id                :integer
 #  score                   :float            default(0.0), not null

app/serializers/category_serializer.rb

@@ -26,17 +26,13 @@ class CategorySerializer < SiteCategorySerializer
              :custom_fields,
              :topic_featured_link_allowed,
              :search_priority,
-             :reviewable_by_group_name,
+             :moderating_group_ids,
              :default_slow_mode_seconds
 
   has_one :category_setting, serializer: CategorySettingSerializer, embed: :objects
 
-  def reviewable_by_group_name
+  def include_moderating_group_ids?
-    object.reviewable_by_group.name
+    SiteSetting.enable_category_group_moderation?
-  end
-
-  def include_reviewable_by_group_name?
-    SiteSetting.enable_category_group_moderation? && object.reviewable_by_group_id.present?
   end
 
   def include_category_setting?

db/migrate/20240828191047_create_category_moderation_groups.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class CreateCategoryModerationGroups < ActiveRecord::Migration[7.1]
+  def change
+    create_table :category_moderation_groups do |t|
+      t.integer :category_id
+      t.integer :group_id
+
+      t.timestamps
+    end
+
+    add_index :category_moderation_groups, %i[category_id group_id], unique: true
+
+    execute <<~SQL
+      INSERT INTO category_moderation_groups (category_id, group_id, created_at, updated_at)
+      SELECT id, reviewable_by_group_id, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP
+      FROM categories
+      WHERE reviewable_by_group_id IS NOT NULL
+    SQL
+  end
+end

lib/guardian.rb

@@ -136,17 +136,14 @@ class Guardian
     return false if !category
     return false if !category_group_moderation_allowed?
 
-    reviewable_by_group_id = category.reviewable_by_group_id
+    @group_moderator_categories ||= {}
-    return false if reviewable_by_group_id.blank?
 
-    @category_group_moderator_groups ||= {}
+    if @group_moderator_categories.key?(category.id)
-
+      @group_moderator_categories[category.id]
-    if @category_group_moderator_groups.key?(reviewable_by_group_id)
-      @category_group_moderator_groups[reviewable_by_group_id]
     else
-      @category_group_moderator_groups[
+      @group_moderator_categories[category.id] = category_group_moderator_scope.exists?(
-        reviewable_by_group_id
+        id: category.id,
-      ] = category_group_moderator_scope.exists?("categories.id": category.id)
+      )
     end
   end
 
@@ -692,8 +689,9 @@ class Guardian
   end
 
   def category_group_moderator_scope
-    Category.joins(
+    Category
-      "INNER JOIN group_users ON group_users.group_id = categories.reviewable_by_group_id",
+      .joins(:category_moderation_groups)
-    ).where("group_users.user_id = ?", user.id)
+      .joins("INNER JOIN group_users ON group_users.group_id = category_moderation_groups.group_id")
+      .where("group_users.user_id": user.id)
   end
 end

lib/guardian/user_guardian.rb

@@ -171,8 +171,13 @@ module UserGuardian
       (
         SiteSetting.enable_category_group_moderation &&
           Reviewable
-            .where(reviewable_by_group_id: @user.group_users.pluck(:group_id))
+            .joins(
-            .where("category_id IS NULL or category_id IN (?)", allowed_category_ids)
+              "INNER JOIN category_moderation_groups ON category_moderation_groups.category_id = reviewables.category_id",
+            )
+            .where(
+              category_id: allowed_category_ids,
+              "category_moderation_groups.group_id": @user.group_users.pluck(:group_id),
+            )
             .exists?
       )
   end

lib/post_action_creator.rb

@@ -364,9 +364,13 @@ class PostActionCreator
       create_args[:subtype] = TopicSubtype.notify_moderators
       create_args[:target_group_names] = [Group[:moderators].name]
 
-      if SiteSetting.enable_category_group_moderation? &&
+      if SiteSetting.enable_category_group_moderation? && @post.topic&.category
-           @post.topic&.category&.reviewable_by_group_id?
+        create_args[:target_group_names].push(
-        create_args[:target_group_names] << @post.topic.category.reviewable_by_group.name
+          *Group
+            .joins(:category_moderation_groups)
+            .where("category_moderation_groups.category_id": @post.topic.category.id)
+            .pluck(:name),
+        )
       end
     end
 

lib/topic_view.rb

@@ -535,16 +535,19 @@ class TopicView
   def category_group_moderator_user_ids
     @category_group_moderator_user_ids ||=
       begin
-        if SiteSetting.enable_category_group_moderation? &&
+        if SiteSetting.enable_category_group_moderation? && @topic.category.present?
-             @topic.category&.reviewable_by_group.present?
           posts_user_ids = Set.new(@posts.map(&:user_id))
           Set.new(
-            @topic
+            GroupUser
-              .category
+              .joins(
-              .reviewable_by_group
+                "INNER JOIN category_moderation_groups ON category_moderation_groups.group_id = group_users.group_id",
-              .group_users
+              )
-              .where(user_id: posts_user_ids)
+              .where(
-              .pluck("distinct user_id"),
+                "category_moderation_groups.category_id": @topic.category.id,
+                user_id: posts_user_ids,
+              )
+              .distinct
+              .pluck(:user_id),
           )
         else
           Set.new

plugins/chat/spec/lib/chat/guardian_extensions_spec.rb

@@ -354,11 +354,11 @@ RSpec.describe Chat::GuardianExtensions do
         context "when enable_category_group_moderation is true" do
           before { SiteSetting.enable_category_group_moderation = true }
 
-          it "returns true if the regular user is part of the reviewable_by_group for the category" do
+          it "returns true if the regular user is part of the reviewable groups for the category" do
             moderator = Fabricate(:user)
             mods = Fabricate(:group)
             mods.add(moderator)
-            category.update!(reviewable_by_group: mods)
+            Fabricate(:category_moderation_group, category:, group: mods)
             expect(Guardian.new(Fabricate(:admin)).can_moderate_chat?(channel.chatable)).to eq(true)
             expect(Guardian.new(moderator).can_moderate_chat?(channel.chatable)).to eq(true)
           end
@@ -443,7 +443,7 @@ RSpec.describe Chat::GuardianExtensions do
                 moderator = Fabricate(:user)
                 mods = Fabricate(:group)
                 mods.add(moderator)
-                chatable.update!(reviewable_by_group: mods)
+                Fabricate(:category_moderation_group, category: chatable, group: mods)
                 expect(Guardian.new(moderator).can_restore_chat?(message, chatable)).to eq(true)
               end
             end

plugins/chat/spec/system/move_message_to_channel_spec.rb

@@ -28,12 +28,14 @@ RSpec.describe "Move message to channel", type: :system do
       fab!(:group_1) { Fabricate(:group) }
       fab!(:channel_1) { Fabricate(:private_category_channel, group: group_1) }
       fab!(:message_1) { Fabricate(:chat_message, chat_channel: channel_1, user: current_user) }
+      fab!(:category_moderation_group) do
+        Fabricate(:category_moderation_group, category: channel_1.category, group: group_1)
+      end
 
       before do
         SiteSetting.enable_category_group_moderation = true
         group_1.add(current_user)
         channel_1.add(current_user)
-        channel_1.chatable.update!(reviewable_by_group_id: group_1.id)
       end
 
       it "is available" do

plugins/discourse-presence/plugin.rb

@@ -59,9 +59,8 @@ after_initialize do
         config.allowed_group_ids += SiteSetting.edit_all_post_groups.split("|").map(&:to_i)
       end
 
-      if SiteSetting.enable_category_group_moderation? &&
+      if SiteSetting.enable_category_group_moderation? && topic.category
-           group_id = topic.category&.reviewable_by_group_id
+        config.allowed_group_ids.push(*topic.category.moderating_groups.pluck(:id))
-        config.allowed_group_ids << group_id
       end
 
       config

plugins/discourse-presence/spec/integration/presence_spec.rb

@@ -73,7 +73,7 @@ RSpec.describe "discourse-presence" do
       expect(c.config.allowed_group_ids).to contain_exactly(Group::AUTO_GROUPS[:staff])
 
       SiteSetting.enable_category_group_moderation = true
-      category.update(reviewable_by_group_id: group.id)
+      Fabricate(:category_moderation_group, category:, group:)
 
       c = PresenceChannel.new("/discourse-presence/edit/#{p.id}", use_cache: false)
       expect(c.config.allowed_group_ids).to contain_exactly(Group::AUTO_GROUPS[:staff], group.id)

spec/fabricators/category_moderation_group_fabricator.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+Fabricator(:category_moderation_group) do
+  category
+  group
+end

spec/jobs/notify_reviewable_spec.rb

@@ -54,8 +54,9 @@ RSpec.describe Jobs::NotifyReviewable do
       moderator.update!(last_seen_reviewable_id: moderator_reviewable.id)
 
       # Content for a group
-      group_reviewable =
+      category = Fabricate(:category)
-        Fabricate(:reviewable, reviewable_by_moderator: true, reviewable_by_group: group)
+      Fabricate(:category_moderation_group, category:, group:)
+      group_reviewable = Fabricate(:reviewable, reviewable_by_moderator: true, category:)
 
       messages =
         MessageBus.track_publish { described_class.new.execute(reviewable_id: group_reviewable.id) }
@@ -85,7 +86,9 @@ RSpec.describe Jobs::NotifyReviewable do
       SiteSetting.enable_category_group_moderation = false
 
       GroupUser.create!(group_id: group.id, user_id: moderator.id)
-      reviewable = Fabricate(:reviewable, reviewable_by_moderator: true, reviewable_by_group: group)
+      category = Fabricate(:category)
+      Fabricate(:category_moderation_group, category:, group:)
+      reviewable = Fabricate(:reviewable, reviewable_by_moderator: true, category:)
 
       messages =
         MessageBus.track_publish("/reviewable_counts") do

spec/jobs/refresh_users_reviewable_counts_spec.rb

@@ -5,20 +5,16 @@ RSpec.describe Jobs::RefreshUsersReviewableCounts do
   fab!(:moderator)
   fab!(:user)
 
-  fab!(:group)
+  fab!(:group) { Fabricate(:group, users: [user]) }
-  fab!(:topic)
+  fab!(:category)
-  fab!(:reviewable1) do
+  fab!(:topic) { Fabricate(:topic, category:) }
-    Fabricate(:reviewable, reviewable_by_group: group, reviewable_by_moderator: true, topic: topic)
+  fab!(:category_moderation_group) { Fabricate(:category_moderation_group, category:, group:) }
-  end
+  fab!(:reviewable1) { Fabricate(:reviewable, reviewable_by_moderator: true, topic:, category:) }
 
   fab!(:reviewable2) { Fabricate(:reviewable, reviewable_by_moderator: false) }
   fab!(:reviewable3) { Fabricate(:reviewable, reviewable_by_moderator: true) }
 
-  before do
+  before { SiteSetting.enable_category_group_moderation = true }
-    SiteSetting.enable_category_group_moderation = true
-    group.add(user)
-    topic.category.update!(reviewable_by_group: group)
-  end
 
   describe "#execute" do
     it "publishes reviewable counts for the members of the specified groups" do

spec/lib/guardian/topic_guardian_spec.rb

@@ -83,7 +83,7 @@ RSpec.describe TopicGuardian do
     it "returns true for group moderator" do
       SiteSetting.enable_category_group_moderation = true
       expect(Guardian.new(user).can_see_deleted_topics?(topic.category)).to eq(false)
-      category.update!(reviewable_by_group_id: group.id)
+      Fabricate(:category_moderation_group, category:, group:)
       group.add(user)
       topic.update!(category: category)
       expect(Guardian.new(user).can_see_deleted_topics?(topic.category)).to eq(true)
@@ -110,7 +110,7 @@ RSpec.describe TopicGuardian do
     it "returns true for group moderator" do
       SiteSetting.enable_category_group_moderation = true
       expect(Guardian.new(user).can_recover_topic?(Topic.with_deleted.last)).to eq(false)
-      category.update!(reviewable_by_group_id: group.id)
+      Fabricate(:category_moderation_group, category:, group:)
       group.add(user)
       topic.update!(category: category)
       expect(Guardian.new(user).can_recover_topic?(Topic.with_deleted.last)).to eq(true)
@@ -255,7 +255,7 @@ RSpec.describe TopicGuardian do
     it "returns the topic ids for topics which are deleted but user is a category moderator of" do
       SiteSetting.enable_category_group_moderation = true
 
-      category.update!(reviewable_by_group_id: group.id)
+      Fabricate(:category_moderation_group, category:, group:)
       group.add(user)
       topic.update!(category: category)
       topic.trash!(admin)

spec/lib/guardian/user_guardian_spec.rb

@@ -415,8 +415,10 @@ RSpec.describe UserGuardian do
       group.add(user)
       guardian = Guardian.new(user)
       SiteSetting.enable_category_group_moderation = true
+      category = Fabricate(:category)
+      Fabricate(:category_moderation_group, category:, group:)
 
-      Fabricate(:reviewable_flagged_post, reviewable_by_group: group, category: nil)
+      Fabricate(:reviewable_flagged_post, category:)
 
       expect(guardian.can_see_review_queue?).to eq(true)
     end
@@ -426,8 +428,10 @@ RSpec.describe UserGuardian do
       group.add(user)
       guardian = Guardian.new(user)
       SiteSetting.enable_category_group_moderation = false
+      category = Fabricate(:category)
+      Fabricate(:category_moderation_group, category:, group:)
 
-      Fabricate(:reviewable_flagged_post, reviewable_by_group: group, category: nil)
+      Fabricate(:reviewable_flagged_post, category:)
 
       expect(guardian.can_see_review_queue?).to eq(false)
     end
@@ -438,8 +442,9 @@ RSpec.describe UserGuardian do
       guardian = Guardian.new(user)
       SiteSetting.enable_category_group_moderation = true
       category = Fabricate(:category, read_restricted: true)
+      Fabricate(:category_moderation_group, category:, group:)
 
-      Fabricate(:reviewable_flagged_post, reviewable_by_group: group, category: category)
+      Fabricate(:reviewable_flagged_post, category: category)
 
       expect(guardian.can_see_review_queue?).to eq(false)
     end

spec/lib/guardian_spec.rb

@@ -1072,7 +1072,8 @@ RSpec.describe Guardian do
 
         expect(Guardian.new(user_gm).can_see?(topic)).to be_falsey
 
-        topic.category.update!(reviewable_by_group_id: group.id, topic_id: post.topic.id)
+        topic.category.update!(topic_id: post.topic.id)
+        Fabricate(:category_moderation_group, category: topic.category, group:)
 
         expect(Guardian.new(user_gm).can_see?(topic)).to be_truthy
       end
@@ -1130,7 +1131,8 @@ RSpec.describe Guardian do
 
         expect(Guardian.new(user_gm).can_see?(post)).to be_falsey
 
-        post.topic.category.update!(reviewable_by_group_id: group.id, topic_id: post.topic.id)
+        post.topic.category.update!(topic_id: post.topic.id)
+        Fabricate(:category_moderation_group, category: post.topic.category, group:)
         expect(Guardian.new(user_gm).can_see?(post)).to be_truthy
       end
 
@@ -1504,7 +1506,7 @@ RSpec.describe Guardian do
       end
 
       it "returns true if user is a member of the appropriate group" do
-        topic.category.update!(reviewable_by_group_id: group_user.group.id)
+        Fabricate(:category_moderation_group, category: topic.category, group: group_user.group)
 
         expect(Guardian.new(group_user.user).can_recover_topic?(topic)).to be_truthy
       end
@@ -1787,7 +1789,7 @@ RSpec.describe Guardian do
         before do
           SiteSetting.enable_category_group_moderation = true
           GroupUser.create!(group_id: group.id, user_id: cat_mod_user.id)
-          post.topic.category.update!(reviewable_by_group_id: group.id)
+          Fabricate(:category_moderation_group, category: post.topic.category, group:)
         end
 
         it "returns true as a category group moderator user" do
@@ -2161,7 +2163,7 @@ RSpec.describe Guardian do
     it "returns true for a group member with reviewable status" do
       SiteSetting.enable_category_group_moderation = true
       GroupUser.create!(group_id: group.id, user_id: user.id)
-      topic.category.update!(reviewable_by_group_id: group.id)
+      Fabricate(:category_moderation_group, category: topic.category, group:)
       expect(Guardian.new(user).can_review_topic?(topic)).to eq(true)
     end
   end
@@ -2182,7 +2184,7 @@ RSpec.describe Guardian do
     it "returns true for a group member with reviewable status" do
       SiteSetting.enable_category_group_moderation = true
       GroupUser.create!(group_id: group.id, user_id: user.id)
-      topic.category.update!(reviewable_by_group_id: group.id)
+      Fabricate(:category_moderation_group, category: topic.category, group:)
       expect(Guardian.new(user).can_close_topic?(topic)).to eq(true)
     end
   end
@@ -2203,7 +2205,7 @@ RSpec.describe Guardian do
     it "returns true for a group member with reviewable status" do
       SiteSetting.enable_category_group_moderation = true
       GroupUser.create!(group_id: group.id, user_id: user.id)
-      topic.category.update!(reviewable_by_group_id: group.id)
+      Fabricate(:category_moderation_group, category: topic.category, group:)
       expect(Guardian.new(user).can_archive_topic?(topic)).to eq(true)
     end
   end
@@ -2224,7 +2226,7 @@ RSpec.describe Guardian do
     it "returns true for a group member with reviewable status" do
       SiteSetting.enable_category_group_moderation = true
       GroupUser.create!(group_id: group.id, user_id: user.id)
-      topic.category.update!(reviewable_by_group_id: group.id)
+      Fabricate(:category_moderation_group, category: topic.category, group:)
       expect(Guardian.new(user).can_edit_staff_notes?(topic)).to eq(true)
     end
   end
@@ -2348,7 +2350,7 @@ RSpec.describe Guardian do
         end
 
         it "returns true if user is a member of the appropriate group" do
-          topic.category.update!(reviewable_by_group_id: group_user.group.id)
+          Fabricate(:category_moderation_group, category: topic.category, group: group_user.group)
 
           expect(Guardian.new(group_user.user).can_delete?(topic)).to be_truthy
         end
@@ -2411,8 +2413,9 @@ RSpec.describe Guardian do
       it "returns true for category moderators" do
         SiteSetting.enable_category_group_moderation = true
         GroupUser.create(group: group, user: user)
-        category = Fabricate(:category, reviewable_by_group_id: group.id)
+        category = Fabricate(:category)
         post.topic.update!(category: category)
+        Fabricate(:category_moderation_group, category:, group:)
 
         expect(Guardian.new(user).can_delete?(post)).to eq(true)
       end
@@ -4399,7 +4402,7 @@ RSpec.describe Guardian do
 
     it "should correctly detect category moderation" do
       group.add(user)
-      category.update!(reviewable_by_group_id: group.id)
+      Fabricate(:category_moderation_group, category:, group:)
       guardian = Guardian.new(user)
 
       # implementation detail, ensure memoization is good (hence testing twice)

spec/lib/new_post_manager_spec.rb

@@ -490,9 +490,12 @@ RSpec.describe NewPostManager do
   end
 
   context "when posting in the category requires approval" do
-    let!(:user) { Fabricate(:user, refresh_auto_groups: true) }
+    fab!(:user) { Fabricate(:user, refresh_auto_groups: true) }
-    let!(:review_group) { Fabricate(:group) }
+    fab!(:review_group) { Fabricate(:group) }
-    let!(:category) { Fabricate(:category, reviewable_by_group_id: review_group.id) }
+    fab!(:category)
+    fab!(:category_moderation_group) do
+      Fabricate(:category_moderation_group, category:, group: review_group)
+    end
 
     context "when new topics require approval" do
       before do

spec/lib/post_destroyer_spec.rb

@@ -306,7 +306,8 @@ RSpec.describe PostDestroyer do
           before do
             SiteSetting.enable_category_group_moderation = true
             review_group = Fabricate(:group)
-            review_category = Fabricate(:category, reviewable_by_group_id: review_group.id)
+            review_category = Fabricate(:category)
+            Fabricate(:category_moderation_group, category: review_category, group: review_group)
             @reply.topic.update!(category: review_category)
             review_group.users << review_user
           end
@@ -552,7 +553,8 @@ RSpec.describe PostDestroyer do
       before do
         SiteSetting.enable_category_group_moderation = true
         review_group = Fabricate(:group)
-        review_category = Fabricate(:category, reviewable_by_group_id: review_group.id)
+        review_category = Fabricate(:category)
+        Fabricate(:category_moderation_group, category: review_category, group: review_group)
         post.topic.update!(category: review_category)
         review_group.users << review_user
       end

spec/lib/post_revisor_spec.rb

@@ -1091,8 +1091,9 @@ RSpec.describe PostRevisor do
 
     context "when logging group moderator edits" do
       fab!(:group_user)
-      fab!(:category) do
+      fab!(:category) { Fabricate(:category, topic: topic) }
-        Fabricate(:category, reviewable_by_group_id: group_user.group.id, topic: topic)
+      fab!(:category_moderation_group) do
+        Fabricate(:category_moderation_group, category:, group: group_user.group)
       end
 
       before do

spec/lib/topic_query_spec.rb

@@ -308,7 +308,8 @@ RSpec.describe TopicQuery do
       group_moderator = Fabricate(:user)
       group = Fabricate(:group)
       group.add(group_moderator)
-      category = Fabricate(:category, reviewable_by_group: group)
+      category = Fabricate(:category)
+      Fabricate(:category_moderation_group, category:, group:)
       _topic = Fabricate(:topic, category: category, deleted_at: 1.year.ago)
 
       expect(TopicQuery.new(admin, status: "deleted").list_latest.topics.size).to eq(1)

spec/lib/validators/post_validator_spec.rb

@@ -386,7 +386,8 @@ RSpec.describe PostValidator do
       SiteSetting.enable_category_group_moderation = true
       group = Fabricate(:group)
       GroupUser.create(group: group, user: user)
-      category = Fabricate(:category, reviewable_by_group_id: group.id)
+      category = Fabricate(:category)
+      Fabricate(:category_moderation_group, category:, group:)
       topic.update!(category: category)
 
       Post.create!(user: other_user, topic: topic, raw: "post number 1", post_number: 1)

spec/models/about_spec.rb

@@ -67,31 +67,28 @@ RSpec.describe About do
   end
 
   describe "#category_moderators" do
-    let(:user) { Fabricate(:user) }
+    fab!(:user)
-    let(:public_cat_moderator) { Fabricate(:user, last_seen_at: 1.month.ago) }
+    fab!(:public_cat_moderator) { Fabricate(:user, last_seen_at: 1.month.ago) }
-    let(:private_cat_moderator) { Fabricate(:user, last_seen_at: 2.month.ago) }
+    fab!(:private_cat_moderator) { Fabricate(:user, last_seen_at: 2.month.ago) }
-    let(:common_moderator) { Fabricate(:user, last_seen_at: 3.month.ago) }
+    fab!(:common_moderator) { Fabricate(:user, last_seen_at: 3.month.ago) }
-    let(:common_moderator_2) { Fabricate(:user, last_seen_at: 4.month.ago) }
+    fab!(:common_moderator_2) { Fabricate(:user, last_seen_at: 4.month.ago) }
 
-    let(:public_group) do
+    fab!(:public_group) do
-      group = Fabricate(:public_group)
+      Fabricate(:public_group, users: [public_cat_moderator, common_moderator, common_moderator_2])
-      group.add(public_cat_moderator)
-      group.add(common_moderator)
-      group.add(common_moderator_2)
-      group
     end
 
-    let(:private_group) do
+    fab!(:private_group) do
-      group = Fabricate(:group)
+      Fabricate(:group, users: [private_cat_moderator, common_moderator, common_moderator_2])
-      group.add(private_cat_moderator)
-      group.add(common_moderator)
-      group.add(common_moderator_2)
-      group
     end
 
-    let!(:public_cat) { Fabricate(:category, reviewable_by_group: public_group) }
+    fab!(:public_cat) { Fabricate(:category) }
-    let!(:private_cat) do
+    fab!(:public_category_moderation_group) do
-      Fabricate(:private_category, group: private_group, reviewable_by_group: private_group)
+      Fabricate(:category_moderation_group, category: public_cat, group: public_group)
+    end
+
+    fab!(:private_cat) { Fabricate(:private_category, group: private_group) }
+    fab!(:private_category_moderation_group) do
+      Fabricate(:category_moderation_group, category: private_cat, group: private_group)
     end
 
     it "lists moderators of the category that the current user can see" do
@@ -120,6 +117,19 @@ RSpec.describe About do
       expect(results.size).to eq(2)
       results.each { |res| expect(res.moderators.size).to eq(2) }
     end
+
+    it "doesn't list the same user twice as a category mod if the user is member of multiple groups" do
+      Fabricate(:category_moderation_group, category: public_cat, group: private_group)
+
+      results = About.new(nil).category_moderators
+      mods = results.find { |r| r.category.id == public_cat.id }.moderators
+      expect(mods.map(&:id)).to contain_exactly(
+        public_cat_moderator.id,
+        common_moderator.id,
+        common_moderator_2.id,
+        private_cat_moderator.id,
+      )
+    end
   end
 
   describe "#admins" do

spec/models/category_spec.rb

@@ -82,51 +82,19 @@ RSpec.describe Category do
     end
   end
 
-  describe "#review_group_id" do
+  describe "#category_moderation_groups" do
     fab!(:group)
-    fab!(:category) { Fabricate(:category_with_definition, reviewable_by_group: group) }
+    fab!(:category) { Fabricate(:category_with_definition) }
     fab!(:topic) { Fabricate(:topic, category: category) }
     fab!(:post) { Fabricate(:post, topic: topic) }
+    fab!(:category_moderation_group) { Fabricate(:category_moderation_group, category:, group:) }
     fab!(:user) { Fabricate(:user, refresh_auto_groups: true) }
 
-    it "will add the group to the reviewable" do
+    it "is destroyed if the group is destroyed" do
-      SiteSetting.enable_category_group_moderation = true
+      expect(category.category_moderation_groups).to contain_exactly(category_moderation_group)
-      reviewable = PostActionCreator.spam(user, post).reviewable
-      expect(reviewable.reviewable_by_group_id).to eq(group.id)
-    end
-
-    it "will add the group to the reviewable even if created manually" do
-      SiteSetting.enable_category_group_moderation = true
-      reviewable =
-        ReviewableFlaggedPost.create!(
-          created_by: user,
-          payload: {
-            raw: "test raw",
-          },
-          category: category,
-        )
-      expect(reviewable.reviewable_by_group_id).to eq(group.id)
-    end
-
-    it "will not add add the group to the reviewable" do
-      SiteSetting.enable_category_group_moderation = false
-      reviewable = PostActionCreator.spam(user, post).reviewable
-      expect(reviewable.reviewable_by_group_id).to be_nil
-    end
-
-    it "will nullify the group_id if destroyed" do
       reviewable = PostActionCreator.spam(user, post).reviewable
       group.destroy
-      expect(category.reload.reviewable_by_group).to be_blank
+      expect(category.reload.category_moderation_groups).to be_blank
-      expect(reviewable.reload.reviewable_by_group_id).to be_blank
-    end
-
-    it "will remove the reviewable_by_group if the category is updated" do
-      SiteSetting.enable_category_group_moderation = true
-      reviewable = PostActionCreator.spam(user, post).reviewable
-      category.reviewable_by_group_id = nil
-      category.save!
-      expect(reviewable.reload.reviewable_by_group_id).to be_nil
     end
   end
 

spec/models/post_action_spec.rb

@@ -99,7 +99,7 @@ RSpec.describe PostAction do
       before do
         SiteSetting.enable_category_group_moderation = true
         group.update!(messageable_level: Group::ALIAS_LEVELS[:nobody])
-        post.topic.category.update!(reviewable_by_group_id: group.id)
+        Fabricate(:category_moderation_group, category: post.topic.category, group:)
       end
 
       it "notifies via pm" do

spec/models/reviewable_spec.rb

@@ -131,7 +131,9 @@ RSpec.describe Reviewable, type: :model do
       it "works with the reviewable by group" do
         SiteSetting.enable_category_group_moderation = true
         group = Fabricate(:group)
-        reviewable.reviewable_by_group_id = group.id
+        category = Fabricate(:category)
+        Fabricate(:category_moderation_group, category:, group:)
+        reviewable.category_id = category.id
         reviewable.save!
 
         expect(Reviewable.list_for(user, status: :pending)).to be_empty
@@ -147,7 +149,9 @@ RSpec.describe Reviewable, type: :model do
       it "doesn't allow review by group when disabled" do
         SiteSetting.enable_category_group_moderation = false
         group = Fabricate(:group)
-        reviewable.reviewable_by_group_id = group.id
+        category = Fabricate(:category)
+        Fabricate(:category_moderation_group, category:, group:)
+        reviewable.category_id = category.id
         reviewable.save!
 
         GroupUser.create!(group_id: group.id, user_id: user.id)
@@ -266,12 +270,12 @@ RSpec.describe Reviewable, type: :model do
     fab!(:admin)
     fab!(:moderator)
     fab!(:group)
+    fab!(:category)
     fab!(:user) { Fabricate(:user, groups: [group]) }
     fab!(:admin_reviewable) { Fabricate(:reviewable, reviewable_by_moderator: false) }
     fab!(:mod_reviewable) { Fabricate(:reviewable, reviewable_by_moderator: true) }
-    fab!(:group_reviewable) do
+    fab!(:category_moderation_group) { Fabricate(:category_moderation_group, category:, group:) }
-      Fabricate(:reviewable, reviewable_by_group: group, reviewable_by_moderator: false)
+    fab!(:group_reviewable) { Fabricate(:reviewable, reviewable_by_moderator: false, category:) }
-    end
 
     context "for admins" do
       it "returns a list of pending reviewables that haven't been seen by the user" do
@@ -638,12 +642,12 @@ RSpec.describe Reviewable, type: :model do
 
   describe ".unseen_reviewable_count" do
     fab!(:group)
+    fab!(:category)
     fab!(:user)
     fab!(:admin_reviewable) { Fabricate(:reviewable, reviewable_by_moderator: false) }
     fab!(:mod_reviewable) { Fabricate(:reviewable, reviewable_by_moderator: true) }
-    fab!(:group_reviewable) do
+    fab!(:category_moderation_group) { Fabricate(:category_moderation_group, category:, group:) }
-      Fabricate(:reviewable, reviewable_by_moderator: false, reviewable_by_group: group)
+    fab!(:group_reviewable) { Fabricate(:reviewable, reviewable_by_moderator: false, category:) }
-    end
 
     it "doesn't include reviewables that can't be seen by the user" do
       SiteSetting.enable_category_group_moderation = true

spec/models/user_spec.rb

@@ -3407,8 +3407,9 @@ RSpec.describe User do
       user.update!(groups: [group])
       SiteSetting.enable_category_group_moderation = true
 
-      group_reviewable =
+      category = Fabricate(:category)
-        Fabricate(:reviewable, reviewable_by_moderator: false, reviewable_by_group: group)
+      Fabricate(:category_moderation_group, category:, group:)
+      group_reviewable = Fabricate(:reviewable, reviewable_by_moderator: false, category:)
       mod_reviewable = Fabricate(:reviewable, reviewable_by_moderator: true)
       admin_reviewable = Fabricate(:reviewable, reviewable_by_moderator: false)
 

spec/requests/categories_controller_spec.rb

@@ -517,7 +517,7 @@ RSpec.describe CategoriesController do
                  slug: "hello-cat",
                  auto_close_hours: 72,
                  search_priority: Searchable::PRIORITIES[:ignore],
-                 reviewable_by_group_name: group.name,
+                 moderating_group_ids: [group.id],
                  permissions: {
                    "everyone" => readonly,
                    "staff" => create_post,
@@ -527,7 +527,7 @@ RSpec.describe CategoriesController do
           expect(response.status).to eq(200)
           cat_json = response.parsed_body["category"]
           expect(cat_json).to be_present
-          expect(cat_json["reviewable_by_group_name"]).to eq(group.name)
+          expect(cat_json["moderating_group_ids"]).to eq([group.id])
           expect(cat_json["name"]).to eq("hello")
           expect(cat_json["slug"]).to eq("hello-cat")
           expect(cat_json["color"]).to eq("ff0")
@@ -634,6 +634,10 @@ RSpec.describe CategoriesController do
   end
 
   describe "#update" do
+    fab!(:mod_group_1) { Fabricate(:group) }
+    fab!(:mod_group_2) { Fabricate(:group) }
+    fab!(:mod_group_3) { Fabricate(:group) }
+
     before { Jobs.run_immediately! }
 
     it "requires the user to be logged in" do
@@ -871,6 +875,47 @@ RSpec.describe CategoriesController do
           expect(category.custom_fields).to eq({ "field_1" => "hi" })
           expect(category.form_template_ids.count).to eq(0)
         end
+
+        it "doesn't set category moderation groups if the enable_category_group_moderation setting is false" do
+          SiteSetting.enable_category_group_moderation = false
+
+          put "/categories/#{category.id}.json", params: { moderating_group_ids: [mod_group_1.id] }
+          expect(response.status).to eq(200)
+          expect(category.reload.moderating_groups).to be_blank
+        end
+
+        it "sets category moderation groups if the enable_category_group_moderation setting is true" do
+          SiteSetting.enable_category_group_moderation = true
+
+          put "/categories/#{category.id}.json", params: { moderating_group_ids: [mod_group_1.id] }
+          expect(response.status).to eq(200)
+          expect(category.reload.moderating_groups).to contain_exactly(mod_group_1)
+        end
+
+        it "removes category moderation groups and adds groups according to the moderating_group_ids param" do
+          SiteSetting.enable_category_group_moderation = true
+
+          category.update!(moderating_group_ids: [mod_group_2.id])
+          expect(category.reload.moderating_groups).to contain_exactly(mod_group_2)
+
+          put "/categories/#{category.id}.json",
+              params: {
+                moderating_group_ids: [mod_group_1.id, mod_group_3.id],
+              }
+          expect(response.status).to eq(200)
+          expect(category.reload.moderating_groups).to contain_exactly(mod_group_1, mod_group_3)
+        end
+
+        it "can remove all category moderation groups" do
+          SiteSetting.enable_category_group_moderation = true
+
+          category.update!(moderating_group_ids: [mod_group_2.id, mod_group_1.id])
+          expect(category.reload.moderating_groups).to contain_exactly(mod_group_2, mod_group_1)
+
+          put "/categories/#{category.id}.json", params: { moderating_group_ids: [] }
+          expect(response.status).to eq(200)
+          expect(category.reload.moderating_groups).to be_blank
+        end
       end
     end
   end

spec/requests/posts_controller_spec.rb

@@ -59,7 +59,8 @@ RSpec.shared_examples "finding and showing post" do
       end
 
       it "can find posts in the allowed category" do
-        post.topic.category.update!(reviewable_by_group_id: group.id, topic_id: topic.id)
+        post.topic.category.update!(topic_id: topic.id)
+        Fabricate(:category_moderation_group, category: post.topic.category, group:)
         get url
         expect(response.status).to eq(200)
       end
@@ -602,7 +603,8 @@ RSpec.describe PostsController do
 
       before do
         SiteSetting.enable_category_group_moderation = true
-        post.topic.category.update!(reviewable_by_group_id: group.id, topic_id: topic.id)
+        Fabricate(:category_moderation_group, category: post.topic.category, group:)
+        post.topic.category.update!(topic_id: topic.id)
         sign_in(user_gm)
       end
 
@@ -2880,7 +2882,7 @@ RSpec.describe PostsController do
 
       before do
         SiteSetting.enable_category_group_moderation = true
-        topic.category.update!(reviewable_by_group_id: group.id)
+        Fabricate(:category_moderation_group, category: topic.category, group:)
 
         sign_in(user)
       end
@@ -2903,8 +2905,7 @@ RSpec.describe PostsController do
       end
 
       it "prevents a group moderator from altering notes outside of their category" do
-        moderatable_group = Fabricate(:group)
+        topic.category.category_moderation_groups.where(group:).delete_all
-        topic.category.update!(reviewable_by_group_id: moderatable_group.id)
 
         put "/posts/#{public_post.id}/notice.json", params: { notice: "Hello" }
 

spec/requests/reviewable_claimed_topics_controller_spec.rb

@@ -53,7 +53,7 @@ RSpec.describe ReviewableClaimedTopicsController do
         SiteSetting.reviewable_claiming = "optional"
 
         group = Fabricate(:group)
-        topic.category.update!(reviewable_by_group: group)
+        Fabricate(:category_moderation_group, category: topic.category, group:)
 
         messages =
           MessageBus.track_publish("/reviewable_claimed") do
@@ -106,8 +106,7 @@ RSpec.describe ReviewableClaimedTopicsController do
         not_notified = Fabricate(:user)
 
         group = Fabricate(:group)
-        topic.category.update!(reviewable_by_group: group)
+        Fabricate(:category_moderation_group, category: topic.category, group:)
-        reviewable.update!(reviewable_by_group: group)
 
         notified = Fabricate(:user)
         group.add(notified)
@@ -190,8 +189,7 @@ RSpec.describe ReviewableClaimedTopicsController do
       not_notified = Fabricate(:user)
 
       group = Fabricate(:group)
-      topic.category.update!(reviewable_by_group: group)
+      Fabricate(:category_moderation_group, category: topic.category, group:)
-      reviewable.update!(reviewable_by_group: group)
 
       notified = Fabricate(:user)
       group.add(notified)

spec/requests/topics_controller_spec.rb

@@ -233,7 +233,10 @@ RSpec.describe TopicsController do
     end
 
     describe "moving to a new topic as a group moderator" do
-      fab!(:category) { Fabricate(:category, reviewable_by_group: group_user.group) }
+      fab!(:category)
+      fab!(:category_moderation_group) do
+        Fabricate(:category_moderation_group, category:, group: group_user.group)
+      end
       fab!(:topic) { Fabricate(:topic, category: category) }
       fab!(:p1) { Fabricate(:post, user: group_user.user, post_number: 1, topic: topic) }
       fab!(:p2) { Fabricate(:post, user: group_user.user, post_number: 2, topic: topic) }
@@ -388,7 +391,10 @@ RSpec.describe TopicsController do
     end
 
     describe "moving to an existing topic as a group moderator" do
-      fab!(:category) { Fabricate(:category, reviewable_by_group: group_user.group) }
+      fab!(:category)
+      fab!(:category_moderation_group) do
+        Fabricate(:category_moderation_group, category:, group: group_user.group)
+      end
       fab!(:topic) { Fabricate(:topic, category: category) }
       fab!(:p1) { Fabricate(:post, user: group_user.user, post_number: 1, topic: topic) }
       fab!(:p2) { Fabricate(:post, user: group_user.user, post_number: 2, topic: topic) }
@@ -439,7 +445,10 @@ RSpec.describe TopicsController do
     end
 
     describe "moving chronologically to an existing topic as a group moderator" do
-      fab!(:category) { Fabricate(:category, reviewable_by_group: group_user.group) }
+      fab!(:category)
+      fab!(:category_moderation_group) do
+        Fabricate(:category_moderation_group, category:, group: group_user.group)
+      end
       fab!(:topic) { Fabricate(:topic, category: category) }
       fab!(:p1) do
         Fabricate(
@@ -715,7 +724,10 @@ RSpec.describe TopicsController do
     end
 
     describe "merging into another topic as a group moderator" do
-      fab!(:category) { Fabricate(:category, reviewable_by_group: group_user.group) }
+      fab!(:category)
+      fab!(:category_moderation_group) do
+        Fabricate(:category_moderation_group, category:, group: group_user.group)
+      end
       fab!(:topic) { Fabricate(:topic, category: category) }
       fab!(:p1) { Fabricate(:post, user: post_author1, post_number: 1, topic: topic) }
       fab!(:p2) { Fabricate(:post, user: post_author2, post_number: 2, topic: topic) }
@@ -752,7 +764,10 @@ RSpec.describe TopicsController do
     end
 
     describe "merging chronologically into another topic as a group moderator" do
-      fab!(:category) { Fabricate(:category, reviewable_by_group: group_user.group) }
+      fab!(:category)
+      fab!(:category_moderation_group) do
+        Fabricate(:category_moderation_group, category:, group: group_user.group)
+      end
       fab!(:topic) { Fabricate(:topic, category: category) }
       fab!(:p1) do
         Fabricate(
@@ -1152,7 +1167,10 @@ RSpec.describe TopicsController do
     end
 
     describe "when logged in as a group member with reviewable status" do
-      fab!(:category) { Fabricate(:category, reviewable_by_group: group_user.group) }
+      fab!(:category)
+      fab!(:category_moderation_group) do
+        Fabricate(:category_moderation_group, category:, group: group_user.group)
+      end
       fab!(:topic) { Fabricate(:topic, category: category) }
 
       before do
@@ -4970,7 +4988,7 @@ RSpec.describe TopicsController do
       it "allows a category moderator to create a delete timer" do
         user.update!(trust_level: TrustLevel[4])
         Group.user_trust_level_change!(user.id, user.trust_level)
-        topic.category.update!(reviewable_by_group: user.groups.first)
+        Fabricate(:category_moderation_group, category: topic.category, group: user.groups.first)
 
         sign_in(user)
 

spec/serializers/category_serializer_spec.rb

@@ -4,18 +4,19 @@ RSpec.describe CategorySerializer do
   fab!(:user)
   fab!(:admin)
   fab!(:group)
-  fab!(:category) { Fabricate(:category, reviewable_by_group_id: group.id) }
+  fab!(:category)
+  fab!(:category_moderation_group) { Fabricate(:category_moderation_group, category:, group:) }
 
   it "includes the reviewable by group name if enabled" do
     SiteSetting.enable_category_group_moderation = true
     json = described_class.new(category, scope: Guardian.new, root: false).as_json
-    expect(json[:reviewable_by_group_name]).to eq(group.name)
+    expect(json[:moderating_group_ids]).to eq([group.id])
   end
 
   it "doesn't include the reviewable by group name if disabled" do
     SiteSetting.enable_category_group_moderation = false
     json = described_class.new(category, scope: Guardian.new, root: false).as_json
-    expect(json[:reviewable_by_group_name]).to be_blank
+    expect(json[:moderating_group_ids]).to be_blank
   end
 
   it "includes custom fields" do

spec/serializers/post_serializer_spec.rb

@@ -284,12 +284,12 @@ RSpec.describe PostSerializer do
     fab!(:topic)
     fab!(:group_user)
     fab!(:post) { Fabricate(:post, topic: topic) }
-
+    fab!(:category_moderation_group) do
-    before do
+      Fabricate(:category_moderation_group, category: topic.category, group: group_user.group)
-      SiteSetting.enable_category_group_moderation = true
-      topic.category.update!(reviewable_by_group_id: group_user.group.id)
     end
 
+    before { SiteSetting.enable_category_group_moderation = true }
+
     it "does nothing for regular users" do
       expect(serialized_post_for_user(nil)[:group_moderator]).to eq(nil)
     end

spec/serializers/topic_view_serializer_spec.rb

@@ -454,7 +454,10 @@ RSpec.describe TopicViewSerializer do
 
     context "with can_edit" do
       fab!(:group_user)
-      fab!(:category) { Fabricate(:category, reviewable_by_group: group_user.group) }
+      fab!(:category)
+      fab!(:category_moderation_group) do
+        Fabricate(:category_moderation_group, category:, group: group_user.group)
+      end
       fab!(:topic) { Fabricate(:topic, category: category) }
       let(:user) { group_user.user }