Enable frozen string for lib/gitlab/ci/**/*.rb

Enables frozen string for all remaining files
in lib/gitlab/ci.

Partially addresses #47424.

changelogs/unreleased/frozen-string-enable-lib-gitlab-ci-remain.yml

+---
+title: Enable frozen string for remaining lib/gitlab/ci/**/*.rb
+merge_request:
+author: gfyoung
+type: performance

lib/gitlab/ci/status/build/action.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/cancelable.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/canceled.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/common.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/created.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/erased.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/factory.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/failed.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/failed_allowed.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/manual.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/pending.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/play.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/retried.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/retryable.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/scheduled.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/skipped.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/stop.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/build/unschedule.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/canceled.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/core.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/created.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/extended.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/external/common.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/external/factory.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/factory.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/failed.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/group/common.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/group/factory.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/manual.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/pending.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/pipeline/blocked.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/pipeline/common.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/pipeline/delayed.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/pipeline/factory.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/running.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/scheduled.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/skipped.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/stage/common.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/stage/factory.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/success.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/status/success_warning.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Status

lib/gitlab/ci/trace/chunked_io.rb

+# 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
@@ -66,8 +68,8 @@ module Gitlab
           end
         end
 
-        def read(length = nil, outbuf = "")
-          out = ""
+        def read(length = nil, outbuf = nil)
+          out = []
 
           length ||= size - tell
 
@@ -83,17 +85,18 @@ 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 = chunk_slice_from_offset
@@ -109,7 +112,7 @@ module Gitlab
             end
           end
 
-          out
+          out.join
         end
 
         def write(data)

lib/gitlab/ci/trace/section_parser.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     class Trace

lib/gitlab/ci/trace/stream.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     class Trace
@@ -129,8 +131,7 @@ module Gitlab
           debris = ''
 
           until (buf = read_backward(BUFFER_SIZE)).empty?
-            buf += debris
-            debris, *lines = buf.each_line.to_a
+            debris, *lines = (buf + debris).each_line.to_a
             lines.reverse_each do |line|
               yield(line.force_encoding(Encoding.default_external))
             end

lib/gitlab/ci/variables/collection.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Variables

lib/gitlab/ci/variables/collection/item.rb

+# frozen_string_literal: true
+
 module Gitlab
   module Ci
     module Variables