Fix #4755: No navigation bar (prev/next button) when favgroup in query.

Fix the favgroup navbar not being shown when doing a `favgroup:<id>`
search for a public favgroup belonging to another user.

app/components/post_navbar_component.rb

@@ -1,4 +1,6 @@
 class PostNavbarComponent < ApplicationComponent
+  extend Memoist
+
   attr_reader :post, :current_user, :search
 
   def initialize(post:, current_user:, search: nil)
@@ -18,7 +20,9 @@ class PostNavbarComponent < ApplicationComponent
   end
 
   def favgroups
-    @favgroups ||= current_user.favorite_groups.for_post(post.id).sort_by do |favgroup|
+    favgroups = FavoriteGroup.visible(current_user).for_post(post.id)
+    favgroups = favgroups.where(creator: current_user).or(favgroups.where(id: favgroup_id))
+    favgroups.sort_by do |favgroup|
       [favgroup.id == favgroup_id ? 0 : 1, favgroup.name]
     end
   end
@@ -38,4 +42,6 @@ class PostNavbarComponent < ApplicationComponent
   def query
     @query ||= PostQueryBuilder.new(search)
   end
+
+  memoize :favgroups
 end

test/components/post_navbar_component_test.rb

@@ -46,8 +46,8 @@ class PostNavbarComponentTest < ViewComponent::TestCase
     context "for a post with favgroups" do
       setup do
         as(@user) do
-          @favgroup1 = create(:favorite_group, creator: @user)
-          @favgroup2 = create(:favorite_group, creator: @user)
+          @favgroup1 = create(:favorite_group, creator: @user, is_public: true)
+          @favgroup2 = create(:favorite_group, creator: @user, is_public: false)
           @post.update(tag_string: "favgroup:#{@favgroup1.id} favgroup:#{@favgroup2.id}")
         end
       end
@@ -65,6 +65,18 @@ class PostNavbarComponentTest < ViewComponent::TestCase
         assert_css(".favgroup-navbar[data-selected=true] .favgroup-name", text: "Favgroup: #{@favgroup1.pretty_name}")
         assert_css(".favgroup-navbar[data-selected=false] .favgroup-name", text: "Favgroup: #{@favgroup2.pretty_name}")
       end
+
+      should "show public favgroups that belong to another user when doing a favgroup:<id> search" do
+        render_post_navbar(@post, current_user: create(:user), search: "favgroup:#{@favgroup1.id}")
+
+        assert_css(".favgroup-navbar[data-selected=true] .favgroup-name", text: "Favgroup: #{@favgroup1.pretty_name}")
+      end
+
+      should "not show private favgroups that belong to another user when doing a favgroup:<id> search" do
+        render_post_navbar(@post, current_user: create(:user), search: "favgroup:#{@favgroup2.id}")
+
+        assert_css(".favgroup-navbar .favgroup-name", count: 0)
+      end
     end
   end
 end