Enable frozen string for lib/gitlab/*.rb

151 files changed, 327 insertions, 22 deletions

diff --git a/changelogs/unreleased/frozen-string-enable-lib-gitlab.yml b/changelogs/unreleased/frozen-string-enable-lib-gitlab.yml
new file mode 100644
index 00000000000..d64278eb626
--- /dev/null
+++ b/changelogs/unreleased/frozen-string-enable-lib-gitlab.yml
@@ -0,0 +1,5 @@
+---
+title: Enable frozen string for lib/gitlab/*.rb
+merge_request:
+author: gfyoung
+type: performance
diff --git a/lib/backup/manager.rb b/lib/backup/manager.rb
index afdc6f383c1..a0434a66ef1 100644
--- a/lib/backup/manager.rb
+++ b/lib/backup/manager.rb
@@ -164,7 +164,7 @@ module Backup
 
     def tar_version
       tar_version, _ = Gitlab::Popen.popen(%w(tar --version))
-      tar_version.force_encoding('locale').split("\n").first
+      tar_version.dup.force_encoding('locale').split("\n").first
     end
 
     def skipped?(item)
diff --git a/lib/gitlab/access.rb b/lib/gitlab/access.rb
index b170145f013..ec090aea784 100644
--- a/lib/gitlab/access.rb
+++ b/lib/gitlab/access.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Gitlab::Access module
 #
 # Define allowed roles that can be used
diff --git a/lib/gitlab/action_rate_limiter.rb b/lib/gitlab/action_rate_limiter.rb
index 4cd3bdefda3..c442211e073 100644
--- a/lib/gitlab/action_rate_limiter.rb
+++ b/lib/gitlab/action_rate_limiter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # This class implements a simple rate limiter that can be used to throttle
   # certain actions. Unlike Rack Attack and Rack::Throttle, which operate at
diff --git a/lib/gitlab/allowable.rb b/lib/gitlab/allowable.rb
index 45c2b01dd8f..4518c8a862c 100644
--- a/lib/gitlab/allowable.rb
+++ b/lib/gitlab/allowable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Allowable
     def can?(*args)
diff --git a/lib/gitlab/app_logger.rb b/lib/gitlab/app_logger.rb
index dddcb2538f9..5edec8b3efe 100644
--- a/lib/gitlab/app_logger.rb
+++ b/lib/gitlab/app_logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class AppLogger < Gitlab::Logger
     def self.file_name_noext
diff --git a/lib/gitlab/asciidoc.rb b/lib/gitlab/asciidoc.rb
index 62c41801d75..df8f0470063 100644
--- a/lib/gitlab/asciidoc.rb
+++ b/lib/gitlab/asciidoc.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'asciidoctor'
 require 'asciidoctor/converter/html5'
 require "asciidoctor-plantuml"
diff --git a/lib/gitlab/auth.rb b/lib/gitlab/auth.rb
index a36d551d1d7..d2029a141e7 100644
--- a/lib/gitlab/auth.rb
+++ b/lib/gitlab/auth.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Auth
     MissingPersonalAccessTokenError = Class.new(StandardError)
diff --git a/lib/gitlab/background_migration.rb b/lib/gitlab/background_migration.rb
index 36c85dec544..d72befce571 100644
--- a/lib/gitlab/background_migration.rb
+++ b/lib/gitlab/background_migration.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module BackgroundMigration
     def self.queue
diff --git a/lib/gitlab/base_doorkeeper_controller.rb b/lib/gitlab/base_doorkeeper_controller.rb
index e4227af25d2..b78993aba30 100644
--- a/lib/gitlab/base_doorkeeper_controller.rb
+++ b/lib/gitlab/base_doorkeeper_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # This is a base controller for doorkeeper.
 # It adds the `can?` helper used in the views.
 module Gitlab
diff --git a/lib/gitlab/blame.rb b/lib/gitlab/blame.rb
index 169aac79854..0d79594363e 100644
--- a/lib/gitlab/blame.rb
+++ b/lib/gitlab/blame.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class Blame
     attr_accessor :blob, :commit
diff --git a/lib/gitlab/blob_helper.rb b/lib/gitlab/blob_helper.rb
index 9b3b383b0c8..488c1d85387 100644
--- a/lib/gitlab/blob_helper.rb
+++ b/lib/gitlab/blob_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # This has been extracted from https://github.com/github/linguist/blob/master/lib/linguist/blob_helper.rb
 module Gitlab
   module BlobHelper
diff --git a/lib/gitlab/build_access.rb b/lib/gitlab/build_access.rb
index 08a8f846ca5..37e79413541 100644
--- a/lib/gitlab/build_access.rb
+++ b/lib/gitlab/build_access.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class BuildAccess < UserAccess
     attr_accessor :user, :project
diff --git a/lib/gitlab/changes_list.rb b/lib/gitlab/changes_list.rb
index 9c9e6668e6f..fb75a78a978 100644
--- a/lib/gitlab/changes_list.rb
+++ b/lib/gitlab/changes_list.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class ChangesList
     include Enumerable
diff --git a/lib/gitlab/chat_name_token.rb b/lib/gitlab/chat_name_token.rb
index e63e5437331..8b3c5dc9e8b 100644
--- a/lib/gitlab/chat_name_token.rb
+++ b/lib/gitlab/chat_name_token.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'json'
 
 module Gitlab
diff --git a/lib/gitlab/ci_access.rb b/lib/gitlab/ci_access.rb
index def1373d8cf..d5d3eb804ae 100644
--- a/lib/gitlab/ci_access.rb
+++ b/lib/gitlab/ci_access.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # For backwards compatibility, generic CI (which is a build without a user) is
   # allowed to :build_download_code without any other checks.
diff --git a/lib/gitlab/closing_issue_extractor.rb b/lib/gitlab/closing_issue_extractor.rb
index 7e7aaeeaa17..4ba921569ad 100644
--- a/lib/gitlab/closing_issue_extractor.rb
+++ b/lib/gitlab/closing_issue_extractor.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class ClosingIssueExtractor
     ISSUE_CLOSING_REGEX = begin
diff --git a/lib/gitlab/color_schemes.rb b/lib/gitlab/color_schemes.rb
index 9c4664df903..a5e4065cf09 100644
--- a/lib/gitlab/color_schemes.rb
+++ b/lib/gitlab/color_schemes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # Module containing GitLab's syntax color scheme definitions and helper
   # methods for accessing them.
diff --git a/lib/gitlab/config_helper.rb b/lib/gitlab/config_helper.rb
index 41880069e4c..b7aa03384b7 100644
--- a/lib/gitlab/config_helper.rb
+++ b/lib/gitlab/config_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab::ConfigHelper
   def gitlab_config_features
     Gitlab.config.gitlab.default_projects_features
diff --git a/lib/gitlab/contributions_calendar.rb b/lib/gitlab/contributions_calendar.rb
index 1ffc2639237..c819bffdfd6 100644
--- a/lib/gitlab/contributions_calendar.rb
+++ b/lib/gitlab/contributions_calendar.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class ContributionsCalendar
     attr_reader :contributor
diff --git a/lib/gitlab/contributor.rb b/lib/gitlab/contributor.rb
index c41e92b620f..d74d5a86aa0 100644
--- a/lib/gitlab/contributor.rb
+++ b/lib/gitlab/contributor.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class Contributor
     attr_accessor :email, :name, :commits, :additions, :deletions
diff --git a/lib/gitlab/cross_project_access.rb b/lib/gitlab/cross_project_access.rb
index 6eaed51b64c..4ddc7e02d1b 100644
--- a/lib/gitlab/cross_project_access.rb
+++ b/lib/gitlab/cross_project_access.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class CrossProjectAccess
     class << self
diff --git a/lib/gitlab/current_settings.rb b/lib/gitlab/current_settings.rb
index de7c959e706..477f9101e98 100644
--- a/lib/gitlab/current_settings.rb
+++ b/lib/gitlab/current_settings.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module CurrentSettings
     class << self
diff --git a/lib/gitlab/daemon.rb b/lib/gitlab/daemon.rb
index bd14c7eece3..6d5fc4219fb 100644
--- a/lib/gitlab/daemon.rb
+++ b/lib/gitlab/daemon.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class Daemon
     def self.initialize_instance(*args)
diff --git a/lib/gitlab/database.rb b/lib/gitlab/database.rb
index 42f9605f5ac..68ed53cf64a 100644
--- a/lib/gitlab/database.rb
+++ b/lib/gitlab/database.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Database
     # The max value of INTEGER type is the same between MySQL and PostgreSQL:
@@ -99,11 +101,11 @@ module Gitlab
       order = "#{field} #{direction}"
 
       if postgresql?
-        order << ' NULLS LAST'
+        order = "#{order} NULLS LAST"
       else
         # `field IS NULL` will be `0` for non-NULL columns and `1` for NULL
         # columns. In the (default) ascending order, `0` comes first.
-        order.prepend("#{field} IS NULL, ") if direction == 'ASC'
+        order = "#{field} IS NULL, #{order}" if direction == 'ASC'
       end
 
       order
@@ -113,11 +115,11 @@ module Gitlab
       order = "#{field} #{direction}"
 
       if postgresql?
-        order << ' NULLS FIRST'
+        order = "#{order} NULLS FIRST"
       else
         # `field IS NULL` will be `0` for non-NULL columns and `1` for NULL
         # columns. In the (default) ascending order, `0` comes first.
-        order.prepend("#{field} IS NULL, ") if direction == 'DESC'
+        order = "#{field} IS NULL, #{order}" if direction == 'DESC'
       end
 
       order
@@ -184,7 +186,7 @@ module Gitlab
       EOF
 
       if return_ids
-        sql << 'RETURNING id'
+        sql = "#{sql}RETURNING id"
       end
 
       result = connection.execute(sql)
diff --git a/lib/gitlab/dependency_linker.rb b/lib/gitlab/dependency_linker.rb
index 3192bf6f667..c63d9e5bb71 100644
--- a/lib/gitlab/dependency_linker.rb
+++ b/lib/gitlab/dependency_linker.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module DependencyLinker
     LINKERS = [
diff --git a/lib/gitlab/downtime_check.rb b/lib/gitlab/downtime_check.rb
index 941244694e2..31bb6810391 100644
--- a/lib/gitlab/downtime_check.rb
+++ b/lib/gitlab/downtime_check.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # Checks if a set of migrations requires downtime or not.
   class DowntimeCheck
diff --git a/lib/gitlab/ee_compat_check.rb b/lib/gitlab/ee_compat_check.rb
index ee604e66154..6fc86925f81 100644
--- a/lib/gitlab/ee_compat_check.rb
+++ b/lib/gitlab/ee_compat_check.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # rubocop: disable Rails/Output
 module Gitlab
   # Checks if a set of migrations requires downtime or not.
diff --git a/lib/gitlab/emoji.rb b/lib/gitlab/emoji.rb
index 89cf659bce4..ce1dfb0753c 100644
--- a/lib/gitlab/emoji.rb
+++ b/lib/gitlab/emoji.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Emoji
     extend self
diff --git a/lib/gitlab/encoding_helper.rb b/lib/gitlab/encoding_helper.rb
index 0f336fbaa10..a4a154c80f7 100644
--- a/lib/gitlab/encoding_helper.rb
+++ b/lib/gitlab/encoding_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module EncodingHelper
     extend self
diff --git a/lib/gitlab/environment.rb b/lib/gitlab/environment.rb
index 5e0dd6e7859..b1a9603d3a5 100644
--- a/lib/gitlab/environment.rb
+++ b/lib/gitlab/environment.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Environment
     def self.hostname
diff --git a/lib/gitlab/environment_logger.rb b/lib/gitlab/environment_logger.rb
index 407cc572656..862a516ca71 100644
--- a/lib/gitlab/environment_logger.rb
+++ b/lib/gitlab/environment_logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class EnvironmentLogger < Gitlab::Logger
     def self.file_name_noext
diff --git a/lib/gitlab/exclusive_lease.rb b/lib/gitlab/exclusive_lease.rb
index 12b5e240962..d466d2a514c 100644
--- a/lib/gitlab/exclusive_lease.rb
+++ b/lib/gitlab/exclusive_lease.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'securerandom'
 
 module Gitlab
diff --git a/lib/gitlab/exclusive_lease_helpers.rb b/lib/gitlab/exclusive_lease_helpers.rb
index e998548cff9..4aaf2474763 100644
--- a/lib/gitlab/exclusive_lease_helpers.rb
+++ b/lib/gitlab/exclusive_lease_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # This module provides helper methods which are intregrated with GitLab::ExclusiveLease
   module ExclusiveLeaseHelpers
diff --git a/lib/gitlab/fake_application_settings.rb b/lib/gitlab/fake_application_settings.rb
index 2c827265d8c..db1aeeea8d3 100644
--- a/lib/gitlab/fake_application_settings.rb
+++ b/lib/gitlab/fake_application_settings.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # This class extends an OpenStruct object by adding predicate methods to mimic
 # ActiveRecord access. We rely on the initial values being true or false to
 # determine whether to define a predicate method because for a newly-added
diff --git a/lib/gitlab/favicon.rb b/lib/gitlab/favicon.rb
index 050a1ad3a0b..1ae2f9dfd93 100644
--- a/lib/gitlab/favicon.rb
+++ b/lib/gitlab/favicon.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class Favicon
     class << self
diff --git a/lib/gitlab/file_detector.rb b/lib/gitlab/file_detector.rb
index da62ed2fb16..4d89ee5a669 100644
--- a/lib/gitlab/file_detector.rb
+++ b/lib/gitlab/file_detector.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'set'
 
 module Gitlab
diff --git a/lib/gitlab/file_finder.rb b/lib/gitlab/file_finder.rb
index af8270c8db8..b4db3f93c9c 100644
--- a/lib/gitlab/file_finder.rb
+++ b/lib/gitlab/file_finder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # This class finds files in a repository by name and content
 # the result is joined and sorted by file name
 module Gitlab
diff --git a/lib/gitlab/file_markdown_link_builder.rb b/lib/gitlab/file_markdown_link_builder.rb
index 5386656efe7..180140e7da2 100644
--- a/lib/gitlab/file_markdown_link_builder.rb
+++ b/lib/gitlab/file_markdown_link_builder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Builds the markdown link of a file
 # It needs the methods filename and secure_url (final destination url) to be defined.
 module Gitlab
@@ -8,7 +10,7 @@ module Gitlab
       return unless name = markdown_name
 
       markdown = "[#{name.gsub(']', '\\]')}](#{secure_url})"
-      markdown.prepend("!") if image_or_video? || dangerous?
+      markdown = "!#{markdown}" if image_or_video? || dangerous?
       markdown
     end
 
diff --git a/lib/gitlab/git.rb b/lib/gitlab/git.rb
index 2913a3e416d..c4aac228b2f 100644
--- a/lib/gitlab/git.rb
+++ b/lib/gitlab/git.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_dependency 'gitlab/encoding_helper'
 
 module Gitlab
diff --git a/lib/gitlab/git_access.rb b/lib/gitlab/git_access.rb
index 240a0d7d1b8..827c04ae035 100644
--- a/lib/gitlab/git_access.rb
+++ b/lib/gitlab/git_access.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Check a user's access to perform a git action. All public methods in this
 # class return an instance of `GitlabAccessStatus`
 module Gitlab
diff --git a/lib/gitlab/git_access_wiki.rb b/lib/gitlab/git_access_wiki.rb
index a5b3902ebf4..3f24001e4ee 100644
--- a/lib/gitlab/git_access_wiki.rb
+++ b/lib/gitlab/git_access_wiki.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class GitAccessWiki < GitAccess
     ERROR_MESSAGES = {
diff --git a/lib/gitlab/git_logger.rb b/lib/gitlab/git_logger.rb
index 9e02ccc0f44..dac4ddd320f 100644
--- a/lib/gitlab/git_logger.rb
+++ b/lib/gitlab/git_logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class GitLogger < Gitlab::Logger
     def self.file_name_noext
diff --git a/lib/gitlab/git_ref_validator.rb b/lib/gitlab/git_ref_validator.rb
index 40636fb204e..a90b69ff42b 100644
--- a/lib/gitlab/git_ref_validator.rb
+++ b/lib/gitlab/git_ref_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Gitaly note: JV: does not need to be migrated, works without a repo.
 
 module Gitlab
diff --git a/lib/gitlab/gitaly_client.rb b/lib/gitlab/gitaly_client.rb
index 4ec87f6a3e7..d99a9f15371 100644
--- a/lib/gitlab/gitaly_client.rb
+++ b/lib/gitlab/gitaly_client.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'base64'
 
 require 'gitaly'
@@ -23,7 +25,7 @@ module Gitlab
         stacks = most_invoked_stack.join('\n') if most_invoked_stack
 
         msg = "GitalyClient##{call_site} called #{invocation_count} times from single request. Potential n+1?"
-        msg << "\nThe following call site called into Gitaly #{max_call_stack} times:\n#{stacks}\n" if stacks
+        msg = "#{msg}\nThe following call site called into Gitaly #{max_call_stack} times:\n#{stacks}\n" if stacks
 
         super(msg)
       end
diff --git a/lib/gitlab/github_import.rb b/lib/gitlab/github_import.rb
index d40b06f969f..14a6d6443ec 100644
--- a/lib/gitlab/github_import.rb
+++ b/lib/gitlab/github_import.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module GithubImport
     def self.refmap
diff --git a/lib/gitlab/gl_id.rb b/lib/gitlab/gl_id.rb
index a53d156b41f..1ed842c2264 100644
--- a/lib/gitlab/gl_id.rb
+++ b/lib/gitlab/gl_id.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module GlId
     def self.gl_id(user)
diff --git a/lib/gitlab/gl_repository.rb b/lib/gitlab/gl_repository.rb
index b54e45de4fe..435b74806e7 100644
--- a/lib/gitlab/gl_repository.rb
+++ b/lib/gitlab/gl_repository.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module GlRepository
     def self.gl_repository(project, is_wiki)
diff --git a/lib/gitlab/gon_helper.rb b/lib/gitlab/gon_helper.rb
index c1726659a90..860c39feb64 100644
--- a/lib/gitlab/gon_helper.rb
+++ b/lib/gitlab/gon_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # rubocop:disable Metrics/AbcSize
 
 module Gitlab
diff --git a/lib/gitlab/gpg.rb b/lib/gitlab/gpg.rb
index 8a91e034377..e53c2d00743 100644
--- a/lib/gitlab/gpg.rb
+++ b/lib/gitlab/gpg.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Gpg
     extend self
diff --git a/lib/gitlab/graphql.rb b/lib/gitlab/graphql.rb
index 04a89432230..74c04e5380e 100644
--- a/lib/gitlab/graphql.rb
+++ b/lib/gitlab/graphql.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Graphql
     StandardGraphqlError = Class.new(StandardError)
diff --git a/lib/gitlab/group_hierarchy.rb b/lib/gitlab/group_hierarchy.rb
index 8fbfa1a86bf..c940ea7305e 100644
--- a/lib/gitlab/group_hierarchy.rb
+++ b/lib/gitlab/group_hierarchy.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # Retrieving of parent or child groups based on a base ActiveRecord relation.
   #
diff --git a/lib/gitlab/highlight.rb b/lib/gitlab/highlight.rb
index 0b6cc893db1..83095acc528 100644
--- a/lib/gitlab/highlight.rb
+++ b/lib/gitlab/highlight.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class Highlight
     TIMEOUT_BACKGROUND = 30.seconds
diff --git a/lib/gitlab/http.rb b/lib/gitlab/http.rb
index 538b51c0008..bcd9e2be35f 100644
--- a/lib/gitlab/http.rb
+++ b/lib/gitlab/http.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # This class is used as a proxy for all outbounding http connection
 # coming from callbacks, services and hooks. The direct use of the HTTParty
 # is discouraged because it can lead to several security problems, like SSRF
diff --git a/lib/gitlab/http_io.rb b/lib/gitlab/http_io.rb
index ce24817db54..9d7763fc5ac 100644
--- a/lib/gitlab/http_io.rb
+++ b/lib/gitlab/http_io.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 ##
 # This class is compatible with IO class (https://ruby-doc.org/core-2.3.1/IO.html)
 # source: https://gitlab.com/snippets/1685610
@@ -73,8 +75,8 @@ module Gitlab
       end
     end
 
-    def read(length = nil, outbuf = "")
-      out = ""
+    def read(length = nil, outbuf = nil)
+      out = []
 
       length ||= size - tell
 
@@ -90,17 +92,18 @@ module Gitlab
         length -= chunk_data.bytesize
       end
 
+      out = out.join
+
       # If outbuf is passed, we put the output into the buffer. This supports IO.copy_stream functionality
       if outbuf
-        outbuf.slice!(0, outbuf.bytesize)
-        outbuf << out
+        outbuf.replace(out)
       end
 
       out
     end
 
     def readline
-      out = ""
+      out = []
 
       until eof?
         data = get_chunk
@@ -116,7 +119,7 @@ module Gitlab
         end
       end
 
-      out
+      out.join
     end
 
     def write(data)
diff --git a/lib/gitlab/i18n.rb b/lib/gitlab/i18n.rb
index 7346eab9e76..7e0398f09af 100644
--- a/lib/gitlab/i18n.rb
+++ b/lib/gitlab/i18n.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module I18n
     extend self
diff --git a/lib/gitlab/identifier.rb b/lib/gitlab/identifier.rb
index a8b93f1d4b2..28a9fe29465 100644
--- a/lib/gitlab/identifier.rb
+++ b/lib/gitlab/identifier.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Detect user based on identifier like
 # key-13 or user-36 or last commit
 module Gitlab
diff --git a/lib/gitlab/import_export.rb b/lib/gitlab/import_export.rb
index 53fe2f8e436..f63a5ece71e 100644
--- a/lib/gitlab/import_export.rb
+++ b/lib/gitlab/import_export.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module ImportExport
     extend self
diff --git a/lib/gitlab/import_formatter.rb b/lib/gitlab/import_formatter.rb
index 4e611e7f16c..d4ba4d1181d 100644
--- a/lib/gitlab/import_formatter.rb
+++ b/lib/gitlab/import_formatter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class ImportFormatter
     def comment(author, date, body)
diff --git a/lib/gitlab/import_sources.rb b/lib/gitlab/import_sources.rb
index f7f5c5787f6..f46bb837cf7 100644
--- a/lib/gitlab/import_sources.rb
+++ b/lib/gitlab/import_sources.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Gitlab::ImportSources module
 #
 # Define import sources that can be used
diff --git a/lib/gitlab/incoming_email.rb b/lib/gitlab/incoming_email.rb
index d323cb9dadf..20fc8226611 100644
--- a/lib/gitlab/incoming_email.rb
+++ b/lib/gitlab/incoming_email.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module IncomingEmail
     UNSUBSCRIBE_SUFFIX = '+unsubscribe'.freeze
diff --git a/lib/gitlab/insecure_key_fingerprint.rb b/lib/gitlab/insecure_key_fingerprint.rb
index f85b6e9197f..e4f0e9d2c73 100644
--- a/lib/gitlab/insecure_key_fingerprint.rb
+++ b/lib/gitlab/insecure_key_fingerprint.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   #
   # Calculates the fingerprint of a given key without using
diff --git a/lib/gitlab/issuable_metadata.rb b/lib/gitlab/issuable_metadata.rb
index 0c9de72329c..351d15605e0 100644
--- a/lib/gitlab/issuable_metadata.rb
+++ b/lib/gitlab/issuable_metadata.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module IssuableMetadata
     def issuable_meta_data(issuable_collection, collection_type)
diff --git a/lib/gitlab/issuable_sorter.rb b/lib/gitlab/issuable_sorter.rb
index d392214867a..42bbfb32d0b 100644
--- a/lib/gitlab/issuable_sorter.rb
+++ b/lib/gitlab/issuable_sorter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module IssuableSorter
     class << self
diff --git a/lib/gitlab/issuables_count_for_state.rb b/lib/gitlab/issuables_count_for_state.rb
index b5657a36998..659fb1472d2 100644
--- a/lib/gitlab/issuables_count_for_state.rb
+++ b/lib/gitlab/issuables_count_for_state.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # Class for counting and caching the number of issuables per state.
   class IssuablesCountForState
diff --git a/lib/gitlab/issues_labels.rb b/lib/gitlab/issues_labels.rb
index b8ca7f2f55f..17c9cb969df 100644
--- a/lib/gitlab/issues_labels.rb
+++ b/lib/gitlab/issues_labels.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class IssuesLabels
     class << self
diff --git a/lib/gitlab/job_waiter.rb b/lib/gitlab/job_waiter.rb
index f7a8eae0be4..e97e961771c 100644
--- a/lib/gitlab/job_waiter.rb
+++ b/lib/gitlab/job_waiter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # JobWaiter can be used to wait for a number of Sidekiq jobs to complete.
   #
diff --git a/lib/gitlab/json_logger.rb b/lib/gitlab/json_logger.rb
index 28e258196ca..3bff77731f6 100644
--- a/lib/gitlab/json_logger.rb
+++ b/lib/gitlab/json_logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class JsonLogger < ::Gitlab::Logger
     def self.file_name_noext
diff --git a/lib/gitlab/kubernetes.rb b/lib/gitlab/kubernetes.rb
index 15c5ece2350..3748fd6b5ef 100644
--- a/lib/gitlab/kubernetes.rb
+++ b/lib/gitlab/kubernetes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # Helper methods to do with Kubernetes network services & resources
   module Kubernetes
diff --git a/lib/gitlab/language_detection.rb b/lib/gitlab/language_detection.rb
index a41435fdb79..7600e60b904 100644
--- a/lib/gitlab/language_detection.rb
+++ b/lib/gitlab/language_detection.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class LanguageDetection
     MAX_LANGUAGES = 5
diff --git a/lib/gitlab/lazy.rb b/lib/gitlab/lazy.rb
index 99594577141..d7a22aa339e 100644
--- a/lib/gitlab/lazy.rb
+++ b/lib/gitlab/lazy.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # A class that can be wrapped around an expensive method call so it's only
   # executed when actually needed.
diff --git a/lib/gitlab/lfs_token.rb b/lib/gitlab/lfs_token.rb
index ead5d566871..fa44bd842b2 100644
--- a/lib/gitlab/lfs_token.rb
+++ b/lib/gitlab/lfs_token.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class LfsToken
     attr_accessor :actor
diff --git a/lib/gitlab/logger.rb b/lib/gitlab/logger.rb
index 3d7c049c17f..128a5dd8936 100644
--- a/lib/gitlab/logger.rb
+++ b/lib/gitlab/logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class Logger < ::Logger
     def self.file_name
diff --git a/lib/gitlab/mail_room.rb b/lib/gitlab/mail_room.rb
index db04356a5e9..78f2d83c1af 100644
--- a/lib/gitlab/mail_room.rb
+++ b/lib/gitlab/mail_room.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'yaml'
 require 'json'
 require_relative 'redis/queues' unless defined?(Gitlab::Redis::Queues)
diff --git a/lib/gitlab/markup_helper.rb b/lib/gitlab/markup_helper.rb
index 49285e35251..142b7d1a472 100644
--- a/lib/gitlab/markup_helper.rb
+++ b/lib/gitlab/markup_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module MarkupHelper
     extend self
diff --git a/lib/gitlab/metrics.rb b/lib/gitlab/metrics.rb
index 7d63ca5627d..61ed20ad623 100644
--- a/lib/gitlab/metrics.rb
+++ b/lib/gitlab/metrics.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Metrics
     include Gitlab::Metrics::InfluxDb
diff --git a/lib/gitlab/multi_collection_paginator.rb b/lib/gitlab/multi_collection_paginator.rb
index fab7a43dd30..5375077d7dc 100644
--- a/lib/gitlab/multi_collection_paginator.rb
+++ b/lib/gitlab/multi_collection_paginator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class MultiCollectionPaginator
     attr_reader :first_collection, :second_collection, :per_page
diff --git a/lib/gitlab/omniauth_initializer.rb b/lib/gitlab/omniauth_initializer.rb
index f33ea0880df..e0ac9eec1f2 100644
--- a/lib/gitlab/omniauth_initializer.rb
+++ b/lib/gitlab/omniauth_initializer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class OmniauthInitializer
     def initialize(devise_config)
diff --git a/lib/gitlab/optimistic_locking.rb b/lib/gitlab/optimistic_locking.rb
index d09bce642b0..ce4ba9f752b 100644
--- a/lib/gitlab/optimistic_locking.rb
+++ b/lib/gitlab/optimistic_locking.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module OptimisticLocking
     module_function
diff --git a/lib/gitlab/other_markup.rb b/lib/gitlab/other_markup.rb
index fc3f21233dd..bc467486eee 100644
--- a/lib/gitlab/other_markup.rb
+++ b/lib/gitlab/other_markup.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # Parser/renderer for markups without other special support code.
   module OtherMarkup
diff --git a/lib/gitlab/otp_key_rotator.rb b/lib/gitlab/otp_key_rotator.rb
index ca5d49eedb9..1d3200aa099 100644
--- a/lib/gitlab/otp_key_rotator.rb
+++ b/lib/gitlab/otp_key_rotator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # The +otp_key_base+ param is used to encrypt the User#otp_secret attribute.
   #
diff --git a/lib/gitlab/pages.rb b/lib/gitlab/pages.rb
index 981ef8faa9a..16df0700b08 100644
--- a/lib/gitlab/pages.rb
+++ b/lib/gitlab/pages.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Pages
     VERSION = File.read(Rails.root.join("GITLAB_PAGES_VERSION")).strip.freeze
diff --git a/lib/gitlab/pages_client.rb b/lib/gitlab/pages_client.rb
index 7b358a3bd1b..3626e53f84c 100644
--- a/lib/gitlab/pages_client.rb
+++ b/lib/gitlab/pages_client.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class PagesClient
     class << self
diff --git a/lib/gitlab/pages_transfer.rb b/lib/gitlab/pages_transfer.rb
index fb215f27cbd..a70dc826f97 100644
--- a/lib/gitlab/pages_transfer.rb
+++ b/lib/gitlab/pages_transfer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class PagesTransfer < ProjectTransfer
     def root_dir
diff --git a/lib/gitlab/path_regex.rb b/lib/gitlab/path_regex.rb
index a78314afdb2..44025650de0 100644
--- a/lib/gitlab/path_regex.rb
+++ b/lib/gitlab/path_regex.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module PathRegex
     extend self
diff --git a/lib/gitlab/performance_bar.rb b/lib/gitlab/performance_bar.rb
index fda61000f6a..4b0c7b5c7f8 100644
--- a/lib/gitlab/performance_bar.rb
+++ b/lib/gitlab/performance_bar.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module PerformanceBar
     ALLOWED_USER_IDS_KEY = 'performance_bar_allowed_user_ids:v2'.freeze
diff --git a/lib/gitlab/plugin.rb b/lib/gitlab/plugin.rb
index 0d1cb16b378..23353f36025 100644
--- a/lib/gitlab/plugin.rb
+++ b/lib/gitlab/plugin.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Plugin
     def self.files
diff --git a/lib/gitlab/plugin_logger.rb b/lib/gitlab/plugin_logger.rb
index c4f6ec3e21d..df3bd56fd2f 100644
--- a/lib/gitlab/plugin_logger.rb
+++ b/lib/gitlab/plugin_logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class PluginLogger < Gitlab::Logger
     def self.file_name_noext
diff --git a/lib/gitlab/polling_interval.rb b/lib/gitlab/polling_interval.rb
index fe4bdfe3831..0f69990df63 100644
--- a/lib/gitlab/polling_interval.rb
+++ b/lib/gitlab/polling_interval.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class PollingInterval
     HEADER_NAME = 'Poll-Interval'.freeze
diff --git a/lib/gitlab/popen.rb b/lib/gitlab/popen.rb
index d0cb7c1a7cf..7fa00d0c68c 100644
--- a/lib/gitlab/popen.rb
+++ b/lib/gitlab/popen.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'fileutils'
 require 'open3'
 
@@ -11,7 +13,7 @@ module Gitlab
     def popen(cmd, path = nil, vars = {}, &block)
       result = popen_with_detail(cmd, path, vars, &block)
 
-      [result.stdout << result.stderr, result.status&.exitstatus]
+      ["#{result.stdout}#{result.stderr}", result.status&.exitstatus]
     end
 
     # Returns Result
diff --git a/lib/gitlab/profiler.rb b/lib/gitlab/profiler.rb
index 15391b1330b..4a62f367835 100644
--- a/lib/gitlab/profiler.rb
+++ b/lib/gitlab/profiler.rb
@@ -1,4 +1,6 @@
 # coding: utf-8
+# frozen_string_literal: true
+
 module Gitlab
   module Profiler
     FILTERED_STRING = '[FILTERED]'.freeze
diff --git a/lib/gitlab/project_search_results.rb b/lib/gitlab/project_search_results.rb
index 71e9cc7f238..3a202d915e3 100644
--- a/lib/gitlab/project_search_results.rb
+++ b/lib/gitlab/project_search_results.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class ProjectSearchResults < SearchResults
     attr_reader :project, :repository_ref
@@ -57,7 +59,8 @@ module Gitlab
       ref = nil
       filename = nil
       basename = nil
-      data = ""
+
+      data = []
       startline = 0
 
       result.each_line.each_with_index do |line, index|
@@ -78,7 +81,7 @@ module Gitlab
         basename: basename,
         ref: ref,
         startline: startline,
-        data: data,
+        data: data.join,
         project_id: project ? project.id : nil
       )
     end
diff --git a/lib/gitlab/project_service_logger.rb b/lib/gitlab/project_service_logger.rb
index e84dca97962..9b0357d3161 100644
--- a/lib/gitlab/project_service_logger.rb
+++ b/lib/gitlab/project_service_logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class ProjectServiceLogger < Gitlab::JsonLogger
     def self.file_name_noext
diff --git a/lib/gitlab/project_template.rb b/lib/gitlab/project_template.rb
index 08f6a54776f..3bfd6ee892c 100644
--- a/lib/gitlab/project_template.rb
+++ b/lib/gitlab/project_template.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class ProjectTemplate
     attr_reader :title, :name, :description, :preview
diff --git a/lib/gitlab/project_transfer.rb b/lib/gitlab/project_transfer.rb
index 690c38737c0..d8f1d1e2316 100644
--- a/lib/gitlab/project_transfer.rb
+++ b/lib/gitlab/project_transfer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # This class is used to move local, unhashed files owned by projects to their new location
   class ProjectTransfer
diff --git a/lib/gitlab/prometheus_client.rb b/lib/gitlab/prometheus_client.rb
index b66253a10e0..45828c77a33 100644
--- a/lib/gitlab/prometheus_client.rb
+++ b/lib/gitlab/prometheus_client.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # Helper methods to interact with Prometheus network services & resources
   class PrometheusClient
diff --git a/lib/gitlab/protocol_access.rb b/lib/gitlab/protocol_access.rb
index 2819c7d062c..efeb1e07d49 100644
--- a/lib/gitlab/protocol_access.rb
+++ b/lib/gitlab/protocol_access.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module ProtocolAccess
     def self.allowed?(protocol)
diff --git a/lib/gitlab/proxy_http_connection_adapter.rb b/lib/gitlab/proxy_http_connection_adapter.rb
index d682289b632..82213098672 100644
--- a/lib/gitlab/proxy_http_connection_adapter.rb
+++ b/lib/gitlab/proxy_http_connection_adapter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # This class is part of the Gitlab::HTTP wrapper. Depending on the value
 # of the global setting allow_local_requests_from_hooks_and_services this adapter
 # will allow/block connection to internal IPs and/or urls.
diff --git a/lib/gitlab/query_limiting.rb b/lib/gitlab/query_limiting.rb
index 9f69a9e4a39..31e6b120e45 100644
--- a/lib/gitlab/query_limiting.rb
+++ b/lib/gitlab/query_limiting.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module QueryLimiting
     # Returns true if we should enable tracking of query counts.
diff --git a/lib/gitlab/recaptcha.rb b/lib/gitlab/recaptcha.rb
index c9efa28d7e7..6559c3e3c57 100644
--- a/lib/gitlab/recaptcha.rb
+++ b/lib/gitlab/recaptcha.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Recaptcha
     def self.load_configurations!
diff --git a/lib/gitlab/reference_counter.rb b/lib/gitlab/reference_counter.rb
index bb26f1b610a..d2dbc6f5ef5 100644
--- a/lib/gitlab/reference_counter.rb
+++ b/lib/gitlab/reference_counter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class ReferenceCounter
     REFERENCE_EXPIRE_TIME = 600
diff --git a/lib/gitlab/reference_extractor.rb b/lib/gitlab/reference_extractor.rb
index 9ff82d628c0..00f817c2399 100644
--- a/lib/gitlab/reference_extractor.rb
+++ b/lib/gitlab/reference_extractor.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # Extract possible GFM references from an arbitrary String for further processing.
   class ReferenceExtractor < Banzai::ReferenceExtractor
diff --git a/lib/gitlab/regex.rb b/lib/gitlab/regex.rb
index 0f26fcfe8cb..7a1a2eaf6c0 100644
--- a/lib/gitlab/regex.rb
+++ b/lib/gitlab/regex.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Regex
     extend self
diff --git a/lib/gitlab/repo_path.rb b/lib/gitlab/repo_path.rb
index 4888184403c..202d310e237 100644
--- a/lib/gitlab/repo_path.rb
+++ b/lib/gitlab/repo_path.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module RepoPath
     NotFoundError = Class.new(StandardError)
diff --git a/lib/gitlab/repository_cache.rb b/lib/gitlab/repository_cache.rb
index a03ce07b6a1..56007574b1b 100644
--- a/lib/gitlab/repository_cache.rb
+++ b/lib/gitlab/repository_cache.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Interface to the Redis-backed cache store
 module Gitlab
   class RepositoryCache
@@ -6,7 +8,7 @@ module Gitlab
     def initialize(repository, extra_namespace: nil, backend: Rails.cache)
       @repository = repository
       @namespace = "#{repository.full_path}:#{repository.project.id}"
-      @namespace += ":#{extra_namespace}" if extra_namespace
+      @namespace = "#{@namespace}:#{extra_namespace}" if extra_namespace
       @backend = backend
     end
 
diff --git a/lib/gitlab/repository_cache_adapter.rb b/lib/gitlab/repository_cache_adapter.rb
index d95024fccf7..931298b5117 100644
--- a/lib/gitlab/repository_cache_adapter.rb
+++ b/lib/gitlab/repository_cache_adapter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module RepositoryCacheAdapter
     extend ActiveSupport::Concern
diff --git a/lib/gitlab/repository_check_logger.rb b/lib/gitlab/repository_check_logger.rb
index 485b596ca57..e90b0a002af 100644
--- a/lib/gitlab/repository_check_logger.rb
+++ b/lib/gitlab/repository_check_logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class RepositoryCheckLogger < Gitlab::Logger
     def self.file_name_noext
diff --git a/lib/gitlab/request_context.rb b/lib/gitlab/request_context.rb
index 8562d4515aa..f8f8ec789ce 100644
--- a/lib/gitlab/request_context.rb
+++ b/lib/gitlab/request_context.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class RequestContext
     class << self
diff --git a/lib/gitlab/request_forgery_protection.rb b/lib/gitlab/request_forgery_protection.rb
index a502ad8a541..b1e478093d3 100644
--- a/lib/gitlab/request_forgery_protection.rb
+++ b/lib/gitlab/request_forgery_protection.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # A module to check CSRF tokens in requests.
 # It's used in API helpers and OmniAuth.
 # Usage: GitLab::RequestForgeryProtection.call(env)
diff --git a/lib/gitlab/request_profiler.rb b/lib/gitlab/request_profiler.rb
index 0c9ab759e81..64593153686 100644
--- a/lib/gitlab/request_profiler.rb
+++ b/lib/gitlab/request_profiler.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'fileutils'
 
 module Gitlab
diff --git a/lib/gitlab/route_map.rb b/lib/gitlab/route_map.rb
index f3952657983..a555bf1d812 100644
--- a/lib/gitlab/route_map.rb
+++ b/lib/gitlab/route_map.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class RouteMap
     FormatError = Class.new(StandardError)
diff --git a/lib/gitlab/routing.rb b/lib/gitlab/routing.rb
index 2c994536060..3b05f181ed2 100644
--- a/lib/gitlab/routing.rb
+++ b/lib/gitlab/routing.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Routing
     extend ActiveSupport::Concern
@@ -47,7 +49,7 @@ module Gitlab
         #
         # `request.fullpath` includes the querystring
         new_path = request.path.sub(%r{/#{path}(/*)(?!.*#{path})}, "/-/#{path}\\1")
-        new_path << "?#{request.query_string}" if request.query_string.present?
+        new_path = "#{new_path}?#{request.query_string}" if request.query_string.present?
 
         new_path
       end
diff --git a/lib/gitlab/search_results.rb b/lib/gitlab/search_results.rb
index d1cf8e10228..5ce3eda2ccb 100644
--- a/lib/gitlab/search_results.rb
+++ b/lib/gitlab/search_results.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class SearchResults
     class FoundBlob
diff --git a/lib/gitlab/seeder.rb b/lib/gitlab/seeder.rb
index 98f005cb61b..84a51773276 100644
--- a/lib/gitlab/seeder.rb
+++ b/lib/gitlab/seeder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # :nocov:
 module DeliverNever
   def deliver_later
diff --git a/lib/gitlab/sentry.rb b/lib/gitlab/sentry.rb
index 6381e94c1d2..24e3866128b 100644
--- a/lib/gitlab/sentry.rb
+++ b/lib/gitlab/sentry.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Sentry
     def self.enabled?
diff --git a/lib/gitlab/setup_helper.rb b/lib/gitlab/setup_helper.rb
index 5b68e4470cd..4a745147858 100644
--- a/lib/gitlab/setup_helper.rb
+++ b/lib/gitlab/setup_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'toml-rb'
 
 module Gitlab
diff --git a/lib/gitlab/shard_health_cache.rb b/lib/gitlab/shard_health_cache.rb
index 3f03f46d4b1..6612347438e 100644
--- a/lib/gitlab/shard_health_cache.rb
+++ b/lib/gitlab/shard_health_cache.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class ShardHealthCache
     HEALTHY_SHARDS_KEY = 'gitlab-healthy-shards'.freeze
diff --git a/lib/gitlab/shell.rb b/lib/gitlab/shell.rb
index 89d2028d7b0..16c1edb2f11 100644
--- a/lib/gitlab/shell.rb
+++ b/lib/gitlab/shell.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Gitaly note: SSH key operations are not part of Gitaly so will never be migrated.
 
 require 'securerandom'
diff --git a/lib/gitlab/shell_adapter.rb b/lib/gitlab/shell_adapter.rb
index 053dd4ab9e0..59fc6ee8dc8 100644
--- a/lib/gitlab/shell_adapter.rb
+++ b/lib/gitlab/shell_adapter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # == GitLab Shell mixin
 #
 # Provide a shortcut to Gitlab::Shell instance by gitlab_shell
diff --git a/lib/gitlab/sherlock.rb b/lib/gitlab/sherlock.rb
index 6360527a7aa..a1471c9de47 100644
--- a/lib/gitlab/sherlock.rb
+++ b/lib/gitlab/sherlock.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'securerandom'
 
 module Gitlab
diff --git a/lib/gitlab/sidekiq_config.rb b/lib/gitlab/sidekiq_config.rb
index c3d7814551c..01f60a98ad8 100644
--- a/lib/gitlab/sidekiq_config.rb
+++ b/lib/gitlab/sidekiq_config.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'yaml'
 require 'set'
 
diff --git a/lib/gitlab/sidekiq_logger.rb b/lib/gitlab/sidekiq_logger.rb
index c1dab87a432..ce82a6f04bb 100644
--- a/lib/gitlab/sidekiq_logger.rb
+++ b/lib/gitlab/sidekiq_logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class SidekiqLogger < Gitlab::Logger
     def self.file_name_noext
diff --git a/lib/gitlab/sidekiq_status.rb b/lib/gitlab/sidekiq_status.rb
index a1f689d94d9..583a970bf4e 100644
--- a/lib/gitlab/sidekiq_status.rb
+++ b/lib/gitlab/sidekiq_status.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # The SidekiqStatus module and its child classes can be used for checking if a
   # Sidekiq job has been processed or not.
diff --git a/lib/gitlab/sidekiq_versioning.rb b/lib/gitlab/sidekiq_versioning.rb
index 9683214ec18..8164a5a9d7a 100644
--- a/lib/gitlab/sidekiq_versioning.rb
+++ b/lib/gitlab/sidekiq_versioning.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module SidekiqVersioning
     def self.install!
diff --git a/lib/gitlab/snippet_search_results.rb b/lib/gitlab/snippet_search_results.rb
index 95e37dfbdab..e360b552f89 100644
--- a/lib/gitlab/snippet_search_results.rb
+++ b/lib/gitlab/snippet_search_results.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class SnippetSearchResults < SearchResults
     include SnippetsHelper
diff --git a/lib/gitlab/ssh_public_key.rb b/lib/gitlab/ssh_public_key.rb
index 6f63ea91ae8..47571239b5c 100644
--- a/lib/gitlab/ssh_public_key.rb
+++ b/lib/gitlab/ssh_public_key.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class SSHPublicKey
     Technology = Struct.new(:name, :key_class, :supported_sizes)
@@ -26,7 +28,7 @@ module Gitlab
 
       return key_content if parts.empty?
 
-      parts.each_with_object("#{ssh_type} ").with_index do |(part, content), index|
+      parts.each_with_object(+"#{ssh_type} ").with_index do |(part, content), index|
         content << part
 
         if Gitlab::SSHPublicKey.new(content).valid?
diff --git a/lib/gitlab/string_placeholder_replacer.rb b/lib/gitlab/string_placeholder_replacer.rb
index 9a2219b7d77..62621255a53 100644
--- a/lib/gitlab/string_placeholder_replacer.rb
+++ b/lib/gitlab/string_placeholder_replacer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class StringPlaceholderReplacer
     # This method accepts the following paras
diff --git a/lib/gitlab/string_range_marker.rb b/lib/gitlab/string_range_marker.rb
index c6ad997a4d4..780fe4c7725 100644
--- a/lib/gitlab/string_range_marker.rb
+++ b/lib/gitlab/string_range_marker.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class StringRangeMarker
     attr_accessor :raw_line, :rich_line, :html_escaped
diff --git a/lib/gitlab/string_regex_marker.rb b/lib/gitlab/string_regex_marker.rb
index 1c87c56c45e..f1982ff914c 100644
--- a/lib/gitlab/string_regex_marker.rb
+++ b/lib/gitlab/string_regex_marker.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class StringRegexMarker < StringRangeMarker
     # rubocop: disable CodeReuse/ActiveRecord
diff --git a/lib/gitlab/task_helpers.rb b/lib/gitlab/task_helpers.rb
index 922418966e9..224bb648d8f 100644
--- a/lib/gitlab/task_helpers.rb
+++ b/lib/gitlab/task_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rainbow/ext/string'
 require 'gitlab/utils/strong_memoize'
 
@@ -39,7 +41,7 @@ module Gitlab
           File.read('/etc/os-release').match(/PRETTY_NAME=\"(.+)\"/)[1]
         end
 
-      os_name.try(:squish!)
+      os_name.try(:squish)
     end
 
     # Prompt the user to input something
diff --git a/lib/gitlab/tcp_checker.rb b/lib/gitlab/tcp_checker.rb
index 6e24e46d0ea..f37a044b607 100644
--- a/lib/gitlab/tcp_checker.rb
+++ b/lib/gitlab/tcp_checker.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class TcpChecker
     attr_reader :remote_host, :remote_port, :local_host, :local_port, :error
diff --git a/lib/gitlab/template_helper.rb b/lib/gitlab/template_helper.rb
index fc498dde723..b0e01697a66 100644
--- a/lib/gitlab/template_helper.rb
+++ b/lib/gitlab/template_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module TemplateHelper
     def prepare_template_environment(file)
diff --git a/lib/gitlab/temporarily_allow.rb b/lib/gitlab/temporarily_allow.rb
index 8d7dacc6c54..000f8ca699d 100644
--- a/lib/gitlab/temporarily_allow.rb
+++ b/lib/gitlab/temporarily_allow.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module TemporarilyAllow
     TEMPORARILY_ALLOW_MUTEX = Mutex.new
diff --git a/lib/gitlab/themes.rb b/lib/gitlab/themes.rb
index 694b01b272c..63860b9cb26 100644
--- a/lib/gitlab/themes.rb
+++ b/lib/gitlab/themes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # Module containing GitLab's application theme definitions and helper methods
   # for accessing them.
diff --git a/lib/gitlab/time_tracking_formatter.rb b/lib/gitlab/time_tracking_formatter.rb
index d615c24149a..cc206010e74 100644
--- a/lib/gitlab/time_tracking_formatter.rb
+++ b/lib/gitlab/time_tracking_formatter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module TimeTrackingFormatter
     extend self
diff --git a/lib/gitlab/timeless.rb b/lib/gitlab/timeless.rb
index 76a1808c8ac..4f974c98c71 100644
--- a/lib/gitlab/timeless.rb
+++ b/lib/gitlab/timeless.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Timeless
     def self.timeless(model, &block)
diff --git a/lib/gitlab/tree_summary.rb b/lib/gitlab/tree_summary.rb
index c2955cd374c..453d78e2f7b 100644
--- a/lib/gitlab/tree_summary.rb
+++ b/lib/gitlab/tree_summary.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class TreeSummary
     include ::Gitlab::Utils::StrongMemoize
diff --git a/lib/gitlab/untrusted_regexp.rb b/lib/gitlab/untrusted_regexp.rb
index dc2d91dfa23..ba1137313d8 100644
--- a/lib/gitlab/untrusted_regexp.rb
+++ b/lib/gitlab/untrusted_regexp.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   # An untrusted regular expression is any regexp containing patterns sourced
   # from user input.
diff --git a/lib/gitlab/update_path_error.rb b/lib/gitlab/update_path_error.rb
index 8947ecfb92e..bc066bf4143 100644
--- a/lib/gitlab/update_path_error.rb
+++ b/lib/gitlab/update_path_error.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   UpdatePathError = Class.new(StandardError)
 end
diff --git a/lib/gitlab/upgrader.rb b/lib/gitlab/upgrader.rb
index 024be6aca44..ccab0e4dd73 100644
--- a/lib/gitlab/upgrader.rb
+++ b/lib/gitlab/upgrader.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class Upgrader
     def execute
diff --git a/lib/gitlab/uploads_transfer.rb b/lib/gitlab/uploads_transfer.rb
index 7d7400bdabf..e0e7084e27e 100644
--- a/lib/gitlab/uploads_transfer.rb
+++ b/lib/gitlab/uploads_transfer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class UploadsTransfer < ProjectTransfer
     def root_dir
diff --git a/lib/gitlab/url_blocker.rb b/lib/gitlab/url_blocker.rb
index 3b483f27e70..7735b736689 100644
--- a/lib/gitlab/url_blocker.rb
+++ b/lib/gitlab/url_blocker.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'resolv'
 
 module Gitlab
diff --git a/lib/gitlab/url_builder.rb b/lib/gitlab/url_builder.rb
index e64033b0dba..f86d599e4cb 100644
--- a/lib/gitlab/url_builder.rb
+++ b/lib/gitlab/url_builder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class UrlBuilder
     include Gitlab::Routing
diff --git a/lib/gitlab/url_sanitizer.rb b/lib/gitlab/url_sanitizer.rb
index 29672d68cad..035268bc4f2 100644
--- a/lib/gitlab/url_sanitizer.rb
+++ b/lib/gitlab/url_sanitizer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class UrlSanitizer
     ALLOWED_SCHEMES = %w[http https ssh git].freeze
diff --git a/lib/gitlab/usage_data.rb b/lib/gitlab/usage_data.rb
index 5097c3253c9..cc0817bdcd2 100644
--- a/lib/gitlab/usage_data.rb
+++ b/lib/gitlab/usage_data.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class UsageData
     class << self
diff --git a/lib/gitlab/user_access.rb b/lib/gitlab/user_access.rb
index 27560abfb96..980a8014409 100644
--- a/lib/gitlab/user_access.rb
+++ b/lib/gitlab/user_access.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class UserAccess
     extend Gitlab::Cache::RequestCache
diff --git a/lib/gitlab/utils.rb b/lib/gitlab/utils.rb
index aeda66763e8..2c92458f777 100644
--- a/lib/gitlab/utils.rb
+++ b/lib/gitlab/utils.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Utils
     extend self
diff --git a/lib/gitlab/version_info.rb b/lib/gitlab/version_info.rb
index 6ee41e85cc9..aa6d5310161 100644
--- a/lib/gitlab/version_info.rb
+++ b/lib/gitlab/version_info.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class VersionInfo
     include Comparable
diff --git a/lib/gitlab/visibility_level.rb b/lib/gitlab/visibility_level.rb
index 2612208a927..a3c7de87765 100644
--- a/lib/gitlab/visibility_level.rb
+++ b/lib/gitlab/visibility_level.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Gitlab::VisibilityLevel module
 #
 # Define allowed public modes that can be used for
diff --git a/lib/gitlab/wiki_file_finder.rb b/lib/gitlab/wiki_file_finder.rb
index f97278f05cd..a00cd65594c 100644
--- a/lib/gitlab/wiki_file_finder.rb
+++ b/lib/gitlab/wiki_file_finder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   class WikiFileFinder < FileFinder
     attr_reader :repository
diff --git a/lib/gitlab/workhorse.rb b/lib/gitlab/workhorse.rb
index 30a8c3578d8..e1f777e9cd1 100644
--- a/lib/gitlab/workhorse.rb
+++ b/lib/gitlab/workhorse.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'base64'
 require 'json'
 require 'securerandom'
@@ -63,7 +65,7 @@ module Gitlab
 
       def send_git_archive(repository, ref:, format:, append_sha:)
         format ||= 'tar.gz'
-        format.downcase!
+        format = format.downcase
         params = repository.archive_metadata(ref, Gitlab.config.gitlab.repository_downloads_path, format, append_sha: append_sha)
         raise "Repository or ref not found" if params.empty?