Fix mentions in Personal snippets

app/models/personal_snippet.rb

@@ -2,4 +2,8 @@
 
 class PersonalSnippet < Snippet
   include WithUploads
+
+  def skip_project_check?
+    true
+  end
 end

changelogs/unreleased/fix-mentions-personal-snippet.yml

+---
+title: Fix bug in personal snippets when somebody is mentioned
+merge_request: 29835
+author: Sashi Kumar
+type: fixed

spec/models/concerns/mentionable_spec.rb

@@ -325,3 +325,20 @@ describe Snippet, 'Mentionable' do
     end
   end
 end
+
+describe PersonalSnippet, 'Mentionable' do
+  describe '#store_mentions!' do
+    it_behaves_like 'mentions in description', :personal_snippet
+    it_behaves_like 'mentions in notes', :personal_snippet do
+      let(:note) { create(:note_on_personal_snippet) }
+      let(:mentionable) { note.noteable }
+    end
+  end
+
+  describe 'load mentions' do
+    it_behaves_like 'load mentions from DB', :personal_snippet do
+      let(:note) { create(:note_on_personal_snippet) }
+      let(:mentionable) { note.noteable }
+    end
+  end
+end

spec/services/snippets/create_service_spec.rb

@@ -252,12 +252,12 @@ describe Snippets::CreateService do
       end
     end
 
-    shared_examples 'after_save callback to store_mentions' do
+    shared_examples 'after_save callback to store_mentions' do |mentionable_class|
       context 'when mentionable attributes change' do
         let(:extra_opts) { { description: "Description with #{user.to_reference}" } }
 
         it 'saves mentions' do
-          expect_next_instance_of(Snippet) do |instance|
+          expect_next_instance_of(mentionable_class) do |instance|
             expect(instance).to receive(:store_mentions!).and_call_original
           end
           expect(snippet.user_mentions.count).to eq 1
@@ -266,7 +266,7 @@ describe Snippets::CreateService do
 
       context 'when mentionable attributes do not change' do
         it 'does not call store_mentions' do
-          expect_next_instance_of(Snippet) do |instance|
+          expect_next_instance_of(mentionable_class) do |instance|
             expect(instance).not_to receive(:store_mentions!)
           end
           expect(snippet.user_mentions.count).to eq 0
@@ -277,7 +277,7 @@ describe Snippets::CreateService do
         it 'does not call store_mentions' do
           base_opts.delete(:title)
 
-          expect_next_instance_of(Snippet) do |instance|
+          expect_next_instance_of(mentionable_class) do |instance|
             expect(instance).not_to receive(:store_mentions!)
           end
           expect(snippet.valid?).to be false
@@ -298,7 +298,7 @@ describe Snippets::CreateService do
       it_behaves_like 'snippet create data is tracked'
       it_behaves_like 'an error service response when save fails'
       it_behaves_like 'creates repository and files'
-      it_behaves_like 'after_save callback to store_mentions'
+      it_behaves_like 'after_save callback to store_mentions', ProjectSnippet
     end
 
     context 'when PersonalSnippet' do
@@ -310,9 +310,7 @@ describe Snippets::CreateService do
       it_behaves_like 'snippet create data is tracked'
       it_behaves_like 'an error service response when save fails'
       it_behaves_like 'creates repository and files'
-      pending('See https://gitlab.com/gitlab-org/gitlab/issues/30742') do
-        it_behaves_like 'after_save callback to store_mentions'
-      end
+      it_behaves_like 'after_save callback to store_mentions', PersonalSnippet
     end
   end
 end

spec/support/shared_examples/models/mentionable_shared_examples.rb

@@ -210,6 +210,10 @@ RSpec.shared_examples 'mentions in description' do |mentionable_type|
       it 'stores no mentions' do
         expect(mentionable.user_mentions.count).to eq 0
       end
+
+      it 'renders description_html correctly' do
+        expect(mentionable.description_html).to include("<a href=\"/#{user.username}\" data-user=\"#{user.id}\"")
+      end
     end
   end