DEV: Route PM only tags to PM tags show route (#17870)

Previously, PM only tags were being routed to the public topic list with
the tag added as a filter. However, the public topic list does not fetch
PMs and hence PM only tags did not provide any value when added to the
Sidebar. This commit changes that by allowing the client to
differentiate PM only tag and thus routes the link to the PM tags show
route.

Counts for PM only tags section links are not supported as of this
commit and will be added in a follow up commit.

spec/serializers/current_user_serializer_spec.rb

@@ -220,45 +220,39 @@ RSpec.describe CurrentUserSerializer do
     end
   end
 
-  describe '#sidebar_tag_names' do
+  describe '#sidebar_tags' do
     fab!(:tag_sidebar_section_link) { Fabricate(:tag_sidebar_section_link, user: user) }
     fab!(:tag_sidebar_section_link_2) { Fabricate(:tag_sidebar_section_link, user: user) }
 
-    it "is not included when SiteSeting.enable_experimental_sidebar_hamburger is false" do
-      SiteSetting.enable_experimental_sidebar_hamburger = false
-
-      json = serializer.as_json
-
-      expect(json[:sidebar_tag_names]).to eq(nil)
-    end
-
-    it "is not included when SiteSeting.tagging_enabled is false" do
-      SiteSetting.enable_experimental_sidebar_hamburger = true
-      SiteSetting.tagging_enabled = false
-
-      json = serializer.as_json
-
-      expect(json[:sidebar_tag_names]).to eq(nil)
-    end
-
     it "is not included when experimental sidebar has not been enabled" do
       SiteSetting.enable_experimental_sidebar_hamburger = false
       SiteSetting.tagging_enabled = true
 
       json = serializer.as_json
 
-      expect(json[:sidebar_tag_names]).to eq(nil)
+      expect(json[:sidebar_tags]).to eq(nil)
     end
 
-    it "is present when experimental sidebar has been enabled" do
+    it "is not included when tagging has not been enabled" do
       SiteSetting.enable_experimental_sidebar_hamburger = true
-      SiteSetting.tagging_enabled = true
+      SiteSetting.tagging_enabled = false
 
       json = serializer.as_json
 
-      expect(json[:sidebar_tag_names]).to contain_exactly(
-        tag_sidebar_section_link.linkable.name,
-        tag_sidebar_section_link_2.linkable.name
+      expect(json[:sidebar_tags]).to eq(nil)
+    end
+
+    it "is present when experimental sidebar and tagging has been enabled" do
+      SiteSetting.enable_experimental_sidebar_hamburger = true
+      SiteSetting.tagging_enabled = true
+
+      tag_sidebar_section_link_2.linkable.update!(pm_topic_count: 5, topic_count: 0)
+
+      json = serializer.as_json
+
+      expect(json[:sidebar_tags]).to contain_exactly(
+        { name: tag_sidebar_section_link.linkable.name, pm_only: false },
+        { name: tag_sidebar_section_link_2.linkable.name, pm_only: true }
       )
     end
   end

spec/serializers/user_serializer_spec.rb

@@ -376,4 +376,52 @@ RSpec.describe UserSerializer do
       expect(json[:user_api_keys][2][:id]).to eq(user_api_key_2.id)
     end
   end
+
+  describe '#sidebar_tags' do
+    fab!(:tag_sidebar_section_link) { Fabricate(:tag_sidebar_section_link, user: user) }
+    fab!(:tag_sidebar_section_link_2) { Fabricate(:tag_sidebar_section_link, user: user) }
+
+    context 'when viewing self' do
+      subject(:json) { UserSerializer.new(user, scope: Guardian.new(user), root: false).as_json }
+
+      it "is not included when SiteSeting.enable_experimental_sidebar_hamburger is false" do
+        SiteSetting.enable_experimental_sidebar_hamburger = false
+        SiteSetting.tagging_enabled = true
+
+        expect(json[:sidebar_tags]).to eq(nil)
+      end
+
+      it "is not included when SiteSeting.tagging_enabled is false" do
+        SiteSetting.enable_experimental_sidebar_hamburger = true
+        SiteSetting.tagging_enabled = false
+
+        expect(json[:sidebar_tags]).to eq(nil)
+      end
+
+      it "is present when experimental sidebar and tagging has been enabled" do
+        SiteSetting.enable_experimental_sidebar_hamburger = true
+        SiteSetting.tagging_enabled = true
+
+        tag_sidebar_section_link_2.linkable.update!(pm_topic_count: 5, topic_count: 0)
+
+        expect(json[:sidebar_tags]).to contain_exactly(
+          { name: tag_sidebar_section_link.linkable.name, pm_only: false },
+          { name: tag_sidebar_section_link_2.linkable.name, pm_only: true }
+        )
+      end
+    end
+
+    context 'when viewing another user' do
+      fab!(:user2) { Fabricate(:user) }
+
+      subject(:json) { UserSerializer.new(user, scope: Guardian.new(user2), root: false).as_json }
+
+      it "is not present even when experimental sidebar and tagging has been enabled" do
+        SiteSetting.enable_experimental_sidebar_hamburger = true
+        SiteSetting.tagging_enabled = true
+
+        expect(json[:sidebar_tags]).to eq(nil)
+      end
+    end
+  end
 end