Initialize wikis on legacy projects during check

app/workers/repository_check/single_repository_worker.rb

 module RepositoryCheck
   class SingleRepositoryWorker
     include Sidekiq::Worker
-  
+
     sidekiq_options retry: false
-  
+
     def perform(project_id)
       project = Project.find(project_id)
       project.update_columns(
@@ -11,20 +11,32 @@ module RepositoryCheck
         last_repository_check_at: Time.now,
       )
     end
-  
+
     private
-  
+
     def check(project)
-      repositories = [project.repository]
-      repositories << project.wiki.repository if project.wiki_enabled?
-      # Use 'map do', not 'all? do', to prevent short-circuiting
-      repositories.map { |repository| git_fsck(repository.path_to_repo) }.all?
+      if !git_fsck(project.repository)
+        false
+      elsif project.wiki_enabled?
+        # Historically some projects never had their wiki repos initialized;
+        # this happens on project creation now. Let's initialize an empty repo
+        # if it is not already there.
+        begin
+          project.create_wiki
+        rescue Rugged::RepositoryError
+        end
+
+        git_fsck(project.wiki.repository)
+      else
+        true
+      end
     end
-  
-    def git_fsck(path)
+
+    def git_fsck(repository)
+      path = repository.path_to_repo
       cmd = %W(nice git --git-dir=#{path} fsck)
       output, status = Gitlab::Popen.popen(cmd)
-  
+
       if status.zero?
         true
       else

spec/workers/repository_check/single_repository_worker_spec.rb

@@ -12,7 +12,7 @@ describe RepositoryCheck::SingleRepositoryWorker do
     subject.perform(project.id)
     expect(project.reload.last_repository_check_failed).to eq(false)
 
-    destroy_wiki(project)
+    break_wiki(project)
     subject.perform(project.id)
 
     expect(project.reload.last_repository_check_failed).to eq(true)
@@ -20,15 +20,38 @@ describe RepositoryCheck::SingleRepositoryWorker do
 
   it 'skips wikis when disabled' do
     project = create(:project_empty_repo, wiki_enabled: false)
-    # Make sure the test would fail if it checked the wiki repo
-    destroy_wiki(project)
+    # Make sure the test would fail if the wiki repo was checked
+    break_wiki(project)
 
     subject.perform(project.id)
 
     expect(project.reload.last_repository_check_failed).to eq(false)
   end
 
-  def destroy_wiki(project)
-    FileUtils.rm_rf(project.wiki.repository.path_to_repo)
+  it 'creates missing wikis' do
+    project = create(:project_empty_repo, wiki_enabled: true)
+    FileUtils.rm_rf(wiki_path(project))
+
+    subject.perform(project.id)
+
+    expect(project.reload.last_repository_check_failed).to eq(false)
+  end
+
+  it 'does not create a wiki if the main repo does not exist at all' do
+    project = create(:project_empty_repo)
+    FileUtils.rm_rf(project.repository.path_to_repo)
+    FileUtils.rm_rf(wiki_path(project))
+
+    subject.perform(project.id)
+
+    expect(File.exist?(wiki_path(project))).to eq(false)
+  end
+
+  def break_wiki(project)
+    FileUtils.rm_rf(wiki_path(project) + '/objects')
+  end
+
+  def wiki_path(project)
+    project.wiki.repository.path_to_repo
   end
 end