Expire snippet repo size caching for push

Replace uncached_size call

app/models/snippet.rb

@@ -267,7 +267,7 @@ class Snippet < ApplicationRecord
   def repository_size_checker
     strong_memoize(:repository_size_checker) do
       ::Gitlab::RepositorySizeChecker.new(
-        current_size_proc: -> { repository._uncached_size.megabytes },
+        current_size_proc: -> { repository.size.megabytes },
         limit: Gitlab::CurrentSettings.snippet_size_limit
       )
     end

app/workers/post_receive.rb

@@ -77,12 +77,8 @@ class PostReceive # rubocop:disable Scalability/IdempotentWorker
 
     return false unless user
 
-    # At the moment, we only expires the repository caches.
-    # In the future we might need to call ProjectCacheWorker
-    # (or the custom class we create) to update the snippet
-    # repository size or any other key.
-    # We might also need to update the repository statistics.
     expire_caches(post_received, snippet.repository)
+    snippet.repository.expire_statistics_caches
   end
 
   # Expire the repository status, branch, and tag cache once per push.

spec/models/snippet_spec.rb

@@ -703,7 +703,7 @@ describe Snippet do
     let(:current_size) { 60 }
 
     before do
-      allow(subject.repository).to receive(:_uncached_size).and_return(current_size)
+      allow(subject.repository).to receive(:size).and_return(current_size)
     end
 
     it 'sets up size checker', :aggregate_failures do

spec/workers/post_receive_spec.rb

@@ -394,6 +394,7 @@ describe PostReceive do
           it 'expires the status cache' do
             expect(snippet.repository).to receive(:empty?).and_return(true)
             expect(snippet.repository).to receive(:expire_status_cache)
+            expect(snippet.repository).to receive(:expire_statistics_caches)
 
             perform
           end