DEV: Limit the number of category sidebar links a user can have (#26756)

app/models/sidebar_section.rb

@@ -2,6 +2,7 @@
 
 class SidebarSection < ActiveRecord::Base
   MAX_TITLE_LENGTH = 30
+  MAX_USER_CATEGORY_LINKS = 100
 
   belongs_to :user
   has_many :sidebar_section_links, -> { order("position") }, dependent: :destroy

app/services/sidebar_section_links_updater.rb

@@ -6,6 +6,7 @@ class SidebarSectionLinksUpdater
       delete_section_links(user: user, linkable_type: "Category")
     else
       category_ids = Category.where(id: category_ids).pluck(:id)
+      category_ids = category_ids[...SidebarSection::MAX_USER_CATEGORY_LINKS]
       update_section_links(user: user, linkable_type: "Category", new_linkable_ids: category_ids)
     end
   end

spec/lib/sidebar_section_links_updater_spec.rb

@@ -7,6 +7,7 @@ RSpec.describe SidebarSectionLinksUpdater do
   describe ".update_category_section_links" do
     fab!(:public_category) { Fabricate(:category) }
     fab!(:public_category2) { Fabricate(:category) }
+    fab!(:public_category3) { Fabricate(:category) }
 
     fab!(:user_category_section_link) do
       Fabricate(:category_sidebar_section_link, linkable: public_category, user: user)
@@ -37,6 +38,17 @@ RSpec.describe SidebarSectionLinksUpdater do
         SidebarSectionLink.where(linkable_type: "Category", user: user).pluck(:linkable_id),
       ).to contain_exactly(public_category.id, public_category2.id)
     end
+
+    it "limits the number of category links a user can have" do
+      stub_const(SidebarSection, :MAX_USER_CATEGORY_LINKS, 2) do
+        described_class.update_category_section_links(
+          user,
+          category_ids: [public_category.id, public_category2.id, public_category3.id],
+        )
+
+        expect(SidebarSectionLink.where(linkable_type: "Category", user: user).count).to eq(2)
+      end
+    end
   end
 
   describe ".update_tag_section_links" do