Remove the Repository#after_import method

What to do after an import is tightly coupled to the type of repository
you are, so it's better to avoid having the method at all.

There's very little in here, so just remove the idea for now. We can
revisit it another time.

app/models/project.rb

@@ -1787,8 +1787,10 @@ class Project < ApplicationRecord
   # rubocop:enable Gitlab/RailsLogger
 
   def after_import
-    repository.after_import
-    wiki.repository.after_import
+    repository.expire_content_cache
+    wiki.repository.expire_content_cache
+
+    DetectRepositoryLanguagesWorker.perform_async(id)
 
     # The import assigns iid values on its own, e.g. by re-using GitHub ids.
     # Flush existing InternalId records for this project for consistency reasons.

app/models/repository.rb

@@ -437,15 +437,6 @@ class Repository
     expire_all_method_caches
   end
 
-  # Runs code after a repository has been forked/imported.
-  def after_import
-    expire_content_cache
-
-    return unless repo_type.project?
-
-    DetectRepositoryLanguagesWorker.perform_async(project.id)
-  end
-
   # Runs code after a new commit has been pushed.
   def after_push_commit(branch_name)
     expire_statistics_caches

ee/spec/models/project_import_state_spec.rb

@@ -12,8 +12,7 @@ describe ProjectImportState, type: :model do
 
       # Works around https://github.com/rspec/rspec-mocks/issues/910
       allow(Project).to receive(:find).with(project.id).and_return(project)
-      expect(project.repository).to receive(:after_import).and_call_original
-      expect(project.wiki.repository).to receive(:after_import).and_call_original
+      expect(project).to receive(:after_import).and_call_original
     end
 
     context 'with a mirrored project' do

spec/features/merge_request/user_sees_diff_spec.rb

@@ -61,10 +61,6 @@ describe 'Merge request > User sees diff', :js do
     let(:merge_request) { create(:merge_request_with_diffs, source_project: forked_project, target_project: project, author: author_user) }
     let(:changelog_id) { Digest::SHA1.hexdigest("CHANGELOG") }
 
-    before do
-      forked_project.repository.after_import
-    end
-
     context 'as author' do
       it 'shows direct edit link', :sidekiq_might_not_need_inline do
         sign_in(author_user)

spec/models/project_import_state_spec.rb

@@ -23,8 +23,7 @@ describe ProjectImportState, type: :model do
 
       # Works around https://github.com/rspec/rspec-mocks/issues/910
       allow(Project).to receive(:find).with(project.id).and_return(project)
-      expect(project.repository).to receive(:after_import).and_call_original
-      expect(project.wiki.repository).to receive(:after_import).and_call_original
+      expect(project).to receive(:after_import).and_call_original
     end
 
     it 'imports a project', :sidekiq_might_not_need_inline do

spec/models/project_spec.rb

@@ -4618,13 +4618,14 @@ describe Project do
     let(:import_state) { create(:import_state, project: project) }
 
     it 'runs the correct hooks' do
-      expect(project.repository).to receive(:after_import)
-      expect(project.wiki.repository).to receive(:after_import)
+      expect(project.repository).to receive(:expire_content_cache)
+      expect(project.wiki.repository).to receive(:expire_content_cache)
       expect(import_state).to receive(:finish)
       expect(project).to receive(:update_project_counter_caches)
       expect(project).to receive(:after_create_default_branch)
       expect(project).to receive(:refresh_markdown_cache!)
       expect(InternalId).to receive(:flush_records!).with(project: project)
+      expect(DetectRepositoryLanguagesWorker).to receive(:perform_async).with(project.id)
 
       project.after_import
     end

spec/models/repository_spec.rb

@@ -1929,32 +1929,6 @@ describe Repository do
     end
   end
 
-  describe '#after_import' do
-    subject { repository.after_import }
-
-    it 'flushes and builds the cache' do
-      expect(repository).to receive(:expire_content_cache)
-
-      subject
-    end
-
-    it 'calls DetectRepositoryLanguagesWorker' do
-      expect(DetectRepositoryLanguagesWorker).to receive(:perform_async)
-
-      subject
-    end
-
-    context 'with a wiki repository' do
-      let(:repository) { project.wiki.repository }
-
-      it 'does not call DetectRepositoryLanguagesWorker' do
-        expect(DetectRepositoryLanguagesWorker).not_to receive(:perform_async)
-
-        subject
-      end
-    end
-  end
-
   describe '#after_push_commit' do
     it 'expires statistics caches' do
       expect(repository).to receive(:expire_statistics_caches)

spec/support/helpers/project_forks_helper.rb

@@ -59,7 +59,7 @@ module ProjectForksHelper
         bare_repo: TestEnv.forked_repo_path_bare,
         refs: TestEnv::FORKED_BRANCH_SHA
       )
-      forked_project.repository.after_import
+      forked_project.repository.expire_content_cache
 
       forked_project
     end