Enable frozen string in lib/api and lib/backup

Partially addresses #47424.

Had to make changes to spec files because
stubbing methods on frozen objects is a mess
in RSpec and leads to failures:

https://github.com/rspec/rspec-mocks/issues/1190

13 files changed, 26 insertions, 0 deletions

diff --git a/lib/api/helpers/badges_helpers.rb b/lib/api/helpers/badges_helpers.rb
index 1f8afbf3c90..46ce5b4e7b5 100644
--- a/lib/api/helpers/badges_helpers.rb
+++ b/lib/api/helpers/badges_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module BadgesHelpers
diff --git a/lib/api/helpers/common_helpers.rb b/lib/api/helpers/common_helpers.rb
index 9993caa5249..7551ca50a7f 100644
--- a/lib/api/helpers/common_helpers.rb
+++ b/lib/api/helpers/common_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module CommonHelpers
diff --git a/lib/api/helpers/custom_attributes.rb b/lib/api/helpers/custom_attributes.rb
index 3bbe827967e..88208226c40 100644
--- a/lib/api/helpers/custom_attributes.rb
+++ b/lib/api/helpers/custom_attributes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module CustomAttributes
diff --git a/lib/api/helpers/custom_validators.rb b/lib/api/helpers/custom_validators.rb
index dd4f6c41131..23b1cd1ad45 100644
--- a/lib/api/helpers/custom_validators.rb
+++ b/lib/api/helpers/custom_validators.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module CustomValidators
diff --git a/lib/api/helpers/headers_helpers.rb b/lib/api/helpers/headers_helpers.rb
index c9c44e3c218..7553af9d156 100644
--- a/lib/api/helpers/headers_helpers.rb
+++ b/lib/api/helpers/headers_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module HeadersHelpers
diff --git a/lib/api/helpers/internal_helpers.rb b/lib/api/helpers/internal_helpers.rb
index 83151be82ad..4eaaca96b49 100644
--- a/lib/api/helpers/internal_helpers.rb
+++ b/lib/api/helpers/internal_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module InternalHelpers
diff --git a/lib/api/helpers/members_helpers.rb b/lib/api/helpers/members_helpers.rb
index 518aaa62aef..73d58ee7f37 100644
--- a/lib/api/helpers/members_helpers.rb
+++ b/lib/api/helpers/members_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # rubocop:disable GitlabSecurity/PublicSend
 
 module API
diff --git a/lib/api/helpers/notes_helpers.rb b/lib/api/helpers/notes_helpers.rb
index 7b1f5c2584b..216b2c45741 100644
--- a/lib/api/helpers/notes_helpers.rb
+++ b/lib/api/helpers/notes_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module NotesHelpers
diff --git a/lib/api/helpers/pagination.rb b/lib/api/helpers/pagination.rb
index 50bcd4e0437..d311cbb5f7e 100644
--- a/lib/api/helpers/pagination.rb
+++ b/lib/api/helpers/pagination.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module Pagination
diff --git a/lib/api/helpers/project_snapshots_helpers.rb b/lib/api/helpers/project_snapshots_helpers.rb
index 94798a8cb51..1b5dc281e38 100644
--- a/lib/api/helpers/project_snapshots_helpers.rb
+++ b/lib/api/helpers/project_snapshots_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module ProjectSnapshotsHelpers
diff --git a/lib/api/helpers/projects_helpers.rb b/lib/api/helpers/projects_helpers.rb
index 98672f2f765..e6a72b949f9 100644
--- a/lib/api/helpers/projects_helpers.rb
+++ b/lib/api/helpers/projects_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module ProjectsHelpers
diff --git a/lib/api/helpers/related_resources_helpers.rb b/lib/api/helpers/related_resources_helpers.rb
index bc7333ca4b3..793ae11b41d 100644
--- a/lib/api/helpers/related_resources_helpers.rb
+++ b/lib/api/helpers/related_resources_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module RelatedResourcesHelpers
diff --git a/lib/api/helpers/runner.rb b/lib/api/helpers/runner.rb
index 61eb88d3331..45d0343bc89 100644
--- a/lib/api/helpers/runner.rb
+++ b/lib/api/helpers/runner.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module API
   module Helpers
     module Runner