Adds the Rubocop ReturnNil cop

This style change enforces `return if ...` instead of
`return nil if ...` to save maintainers a few minor review points

lib/gitlab/background_migration/migrate_events_to_push_event_payloads.rb

@@ -24,7 +24,7 @@ module Gitlab
         def commit_title
           commit = commits.last
-          return nil unless commit && commit[:message]
+          return unless commit && commit[:message]
           index = commit[:message].index("\n")
           message = index ? commit[:message][0..index] : commit[:message]

lib/gitlab/background_migration/populate_untracked_uploads_dependencies.rb

@@ -127,7 +127,7 @@ module Gitlab
           full_path = matchd[1]
           project = Gitlab::BackgroundMigration::PopulateUntrackedUploadsDependencies::Project.find_by_full_path(full_path)
-          return nil unless project
+          return unless project
           project.id
         end

lib/gitlab/bare_repository_import/importer.rb

@@ -108,7 +108,7 @@ module Gitlab
       end
       def find_or_create_groups
-        return nil unless group_path.present?
+        return unless group_path.present?
         log " * Using namespace: #{group_path}"

lib/gitlab/bitbucket_import/importer.rb

@@ -47,7 +47,7 @@ module Gitlab
       # rubocop: disable CodeReuse/ActiveRecord
       def find_user_id(username)
-        return nil unless username
+        return unless username
         return users[username] if users.key?(username)

lib/gitlab/bitbucket_server_import/importer.rb

@@ -65,7 +65,7 @@ module Gitlab
       end
       def find_user_id(email)
-        return nil unless email
+        return unless email
         return users[email] if users.key?(email)

lib/gitlab/ci/ansi2html.rb

@@ -313,7 +313,7 @@ module Gitlab
         def get_term_color_class(color_index, prefix)
           color_name = COLOR[color_index]
-          return nil if color_name.nil?
+          return if color_name.nil?
           get_color_class(["term", prefix, color_name])
         end

lib/gitlab/ci/build/artifacts/metadata.rb

@@ -103,7 +103,7 @@ module Gitlab
           def read_string(gz)
             string_size = read_uint32(gz)
-            return nil unless string_size
+            return unless string_size
             gz.read(string_size)
           end

lib/gitlab/ci/build/artifacts/metadata/entry.rb

@@ -44,7 +44,7 @@ module Gitlab
             end
             def parent
-              return nil unless has_parent?
+              return unless has_parent?
               self.class.new(@path.to_s.chomp(basename), @entries)
             end

lib/gitlab/cycle_analytics/plan_event_fetcher.rb

@@ -40,11 +40,11 @@ module Gitlab
       end
       def first_time_reference_commit(event)
-        return nil unless event && merge_request_diff_commits
+        return unless event && merge_request_diff_commits
         commits = merge_request_diff_commits[event['id'].to_i]
-        return nil if commits.blank?
+        return if commits.blank?
         commits.find do |commit|
           next unless commit[:committed_date] && event['first_mentioned_in_commit_at']

lib/gitlab/database/count/tablesample_count_strategy.rb

@@ -36,7 +36,7 @@ module Gitlab
         def perform_count(model, estimate)
           # If we estimate 0, we may not have statistics at all. Don't use them.
-          return nil unless estimate && estimate > 0
+          return unless estimate && estimate > 0
           if estimate < EXACT_COUNT_THRESHOLD
             # The table is considered small, the assumption here is that

lib/gitlab/diff/file.rb

@@ -75,7 +75,7 @@ module Gitlab
       end
       def line_for_position(pos)
-        return nil unless pos.position_type == 'text'
+        return unless pos.position_type == 'text'
         # This method is normally used to find which line the diff was
         # commented on, and in this context, it's normally the raw diff persisted

lib/gitlab/email/reply_parser.rb

@@ -61,7 +61,7 @@ module Gitlab
       # Force encoding to UTF-8 on a Mail::Message or Mail::Part
       def fix_charset(object)
-        return nil if object.nil?
+        return if object.nil?
         if object.charset
           object.body.decoded.force_encoding(object.charset.gsub(/utf8/i, "UTF-8")).encode("UTF-8").to_s

lib/gitlab/fogbugz_import/importer.rb

@@ -239,7 +239,7 @@ module Gitlab
         res = ::Projects::DownloadService.new(project, link).execute
-        return nil if res.nil?
+        return if res.nil?
         res[:markdown]
       end

lib/gitlab/git/commit.rb

@@ -58,10 +58,10 @@ module Gitlab
           return commit_id if commit_id.is_a?(Gitlab::Git::Commit)
           # Some weird thing?
-          return nil unless commit_id.is_a?(String)
+          return unless commit_id.is_a?(String)
           # This saves us an RPC round trip.
-          return nil if commit_id.include?(':')
+          return if commit_id.include?(':')
           commit = find_commit(repo, commit_id)

lib/gitlab/git/repository.rb

@@ -276,7 +276,7 @@ module Gitlab
       # senddata response.
       def archive_file_path(storage_path, sha, name, format = "tar.gz")
         # Build file path
-        return nil unless name
+        return unless name
         extension =
           case format

lib/gitlab/git/tree.rb

@@ -44,7 +44,7 @@ module Gitlab
             entry[:name] == path_arr[0] && entry[:type] == :tree
           end
-          return nil unless entry
+          return unless entry
           if path_arr.size > 1
             path_arr.shift

lib/gitlab/gitaly_client.rb

@@ -384,13 +384,13 @@ module Gitlab
     # Returns the stacks that calls Gitaly the most times. Used for n+1 detection
     def self.max_stacks
-      return nil unless Gitlab::SafeRequestStore.active?
+      return unless Gitlab::SafeRequestStore.active?
       stack_counter = Gitlab::SafeRequestStore[:stack_counter]
-      return nil unless stack_counter
+      return unless stack_counter
       max = max_call_count
-      return nil if max.zero?
+      return if max.zero?
       stack_counter.select { |_, v| v == max }.keys
     end

lib/gitlab/gitaly_client/blob_service.rb

@@ -27,7 +27,7 @@ module Gitlab
           data << msg.data
         end
-        return nil if blob.oid.blank?
+        return if blob.oid.blank?
         data = data.join

lib/gitlab/gitaly_client/operation_service.rb

@@ -62,7 +62,7 @@ module Gitlab
         end
         branch = response.branch
-        return nil unless branch
+        return unless branch
         target_commit = Gitlab::Git::Commit.decorate(@repository, branch.target_commit)
         Gitlab::Git::Branch.new(@repository, branch.name, target_commit.id, target_commit)

lib/gitlab/highlight.rb

@@ -39,7 +39,7 @@ module Gitlab
     private
     def custom_language
-      return nil unless @language
+      return unless @language
       Rouge::Lexer.find_fancy(@language)
     end