From 83832af984122cbb55718c746f1d3c6e028f3cc7 Mon Sep 17 00:00:00 2001
From: JonJagger <jon@kosli.com>
Date: Thu, 12 Feb 2026 12:37:51 +0000
Subject: [PATCH 1/4] Move to global frozen-string-literals

---
 source/client/client.rb                       | 2 --
 source/client/config/config.ru                | 2 --
 source/client/config/puma.rb                  | 1 -
 source/client/config/up.sh                    | 5 +++--
 source/client/differ.rb                       | 2 --
 source/client/html_demo.rb                    | 2 --
 source/client/http_json_args.rb               | 2 --
 source/client/http_json_hash/http.rb          | 2 --
 source/client/http_json_hash/requester.rb     | 2 --
 source/client/http_json_hash/service.rb       | 2 --
 source/client/http_json_hash/service_error.rb | 2 --
 source/client/http_json_hash/unpacker.rb      | 2 --
 source/client/saver.rb                        | 2 --
 source/server/app.rb                          | 2 --
 source/server/app_base.rb                     | 2 --
 source/server/config/config.ru                | 2 --
 source/server/config/puma.rb                  | 1 -
 source/server/config/up.sh                    | 5 +++--
 source/server/differ.rb                       | 2 --
 source/server/external/disk_writer.rb         | 2 --
 source/server/external/gitter.rb              | 2 --
 source/server/external/http.rb                | 2 --
 source/server/external/saver.rb               | 2 --
 source/server/external/sheller.rb             | 2 --
 source/server/externals.rb                    | 2 --
 source/server/git_diff_parse_filenames.rb     | 2 --
 source/server/git_diff_parser.rb              | 2 --
 source/server/git_differ.rb                   | 2 --
 source/server/http_json_hash/requester.rb     | 2 --
 source/server/http_json_hash/service.rb       | 2 --
 source/server/http_json_hash/service_error.rb | 2 --
 source/server/http_json_hash/unpacker.rb      | 2 --
 source/server/prober.rb                       | 2 --
 source/server/silently.rb                     | 2 --
 source/server/utf8_clean.rb                   | 2 --
 test/client/client_test_base.rb               | 2 --
 test/client/differ_client_test.rb             | 2 --
 test/client/http_response_unpacker_test.rb    | 2 --
 test/client/lib/check_metrics.rb              | 2 --
 test/client/lib/coverage.rb                   | 2 --
 test/client/lib/coverage_metrics_limits.rb    | 2 --
 test/client/lib/id58_test_base.rb             | 2 --
 test/client/lib/run.sh                        | 2 +-
 test/client/lib/simplecov_formatter_json.rb   | 2 --
 test/client/lib/slim_json_reporter.rb         | 2 --
 test/client/lib/test_metrics_limits.rb        | 2 --
 test/server/diff_summary_test.rb              | 2 --
 test/server/differ_test.rb                    | 2 --
 test/server/differ_test_base.rb               | 2 --
 test/server/external_disk_writer_test.rb      | 2 --
 test/server/external_gitter_test.rb           | 2 --
 test/server/external_sheller_test.rb          | 2 --
 test/server/externals_test.rb                 | 2 --
 test/server/git_diff_parse_filenames_test.rb  | 2 --
 test/server/git_diff_parser_test.rb           | 2 --
 test/server/http_adapter_stub.rb              | 2 --
 test/server/http_json_hash/http.rb            | 2 --
 test/server/http_json_hash/requester.rb       | 2 --
 test/server/http_json_hash/service.rb         | 2 --
 test/server/http_json_hash/unpacker.rb        | 2 --
 test/server/http_proxy_response_test.rb       | 2 --
 test/server/lib/check_metrics.rb              | 2 --
 test/server/lib/coverage.rb                   | 2 --
 test/server/lib/coverage_metrics_limits.rb    | 2 --
 test/server/lib/id58_test_base.rb             | 1 -
 test/server/lib/run.sh                        | 2 +-
 test/server/lib/simplecov_formatter_json.rb   | 2 --
 test/server/lib/slim_json_reporter.rb         | 2 --
 test/server/lib/test_metrics_limits.rb        | 2 --
 test/server/prober_test.rb                    | 2 --
 test/server/raising_disk_writer.rb            | 2 --
 test/server/saver.rb                          | 2 --
 test/server/spy_sheller.rb                    | 2 --
 test/server/utf8_clean_test.rb                | 2 --
 74 files changed, 8 insertions(+), 143 deletions(-)

diff --git a/source/client/client.rb b/source/client/client.rb
index 5c81a0b7..ad4313fa 100644
--- a/source/client/client.rb
+++ b/source/client/client.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'http_json_args'
 require 'json'
 require 'rack'
diff --git a/source/client/config/config.ru b/source/client/config/config.ru
index 49100785..f2f1039e 100644
--- a/source/client/config/config.ru
+++ b/source/client/config/config.ru
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 $stdout.sync = true
 $stderr.sync = true
 
diff --git a/source/client/config/puma.rb b/source/client/config/puma.rb
index feb02ae9..ae91e4c5 100755
--- a/source/client/config/puma.rb
+++ b/source/client/config/puma.rb
@@ -1,5 +1,4 @@
 #!/usr/bin/env puma
-# frozen_string_literal: true
 
 environment('production')
 rackup("#{__dir__}/config.ru")
diff --git a/source/client/config/up.sh b/source/client/config/up.sh
index 993c89ef..eab01aef 100755
--- a/source/client/config/up.sh
+++ b/source/client/config/up.sh
@@ -1,9 +1,10 @@
-#!/bin/bash -Eeu
+#!/usr/bin/env bash
+set -Eeu
 
 readonly PORT="${CYBER_DOJO_DIFFER_CLIENT_PORT}"
 readonly MY_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
-export RUBYOPT='-W2'
+export RUBYOPT='-W2 --enable-frozen-string-literal'
 
 puma \
   --port=${PORT} \
diff --git a/source/client/differ.rb b/source/client/differ.rb
index 57d52daa..d63884ce 100644
--- a/source/client/differ.rb
+++ b/source/client/differ.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'http_json_hash/service'
 
 module External
diff --git a/source/client/html_demo.rb b/source/client/html_demo.rb
index bc6385fe..9572afc9 100644
--- a/source/client/html_demo.rb
+++ b/source/client/html_demo.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ'
 
 class HtmlDemo
diff --git a/source/client/http_json_args.rb b/source/client/http_json_args.rb
index 15427c27..0bfb69a2 100644
--- a/source/client/http_json_args.rb
+++ b/source/client/http_json_args.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 class HttpJsonArgs
   def get(path)
     case path
diff --git a/source/client/http_json_hash/http.rb b/source/client/http_json_hash/http.rb
index dcf4a3ac..f6b7f2e5 100644
--- a/source/client/http_json_hash/http.rb
+++ b/source/client/http_json_hash/http.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'net/http'
 
 module HttpJsonHash
diff --git a/source/client/http_json_hash/requester.rb b/source/client/http_json_hash/requester.rb
index 59c293b0..9dcc3622 100644
--- a/source/client/http_json_hash/requester.rb
+++ b/source/client/http_json_hash/requester.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'http'
 require 'json'
 require 'uri'
diff --git a/source/client/http_json_hash/service.rb b/source/client/http_json_hash/service.rb
index 22f759be..be4a61c6 100644
--- a/source/client/http_json_hash/service.rb
+++ b/source/client/http_json_hash/service.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'requester'
 require_relative 'unpacker'
 
diff --git a/source/client/http_json_hash/service_error.rb b/source/client/http_json_hash/service_error.rb
index 68909b32..33a82891 100644
--- a/source/client/http_json_hash/service_error.rb
+++ b/source/client/http_json_hash/service_error.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'json'
 
 module HttpJsonHash
diff --git a/source/client/http_json_hash/unpacker.rb b/source/client/http_json_hash/unpacker.rb
index 50aee331..0fa2388e 100644
--- a/source/client/http_json_hash/unpacker.rb
+++ b/source/client/http_json_hash/unpacker.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'service_error'
 require 'json'
 
diff --git a/source/client/saver.rb b/source/client/saver.rb
index 6e2a2036..a0cb6074 100644
--- a/source/client/saver.rb
+++ b/source/client/saver.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'http_json_hash/service'
 
 module External
diff --git a/source/server/app.rb b/source/server/app.rb
index 047d5139..b373604b 100644
--- a/source/server/app.rb
+++ b/source/server/app.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'app_base'
 require_relative 'differ'
 require_relative 'prober'
diff --git a/source/server/app_base.rb b/source/server/app_base.rb
index ed5aee6c..5a9b6dab 100644
--- a/source/server/app_base.rb
+++ b/source/server/app_base.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'silently'
 silently { require 'sinatra/contrib' } # N x "warning: method redefined"
 require_relative 'http_json_hash/service'
diff --git a/source/server/config/config.ru b/source/server/config/config.ru
index 8d654b6b..340f48da 100644
--- a/source/server/config/config.ru
+++ b/source/server/config/config.ru
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 $stdout.sync = true
 $stderr.sync = true
 
diff --git a/source/server/config/puma.rb b/source/server/config/puma.rb
index feb02ae9..ae91e4c5 100755
--- a/source/server/config/puma.rb
+++ b/source/server/config/puma.rb
@@ -1,5 +1,4 @@
 #!/usr/bin/env puma
-# frozen_string_literal: true
 
 environment('production')
 rackup("#{__dir__}/config.ru")
diff --git a/source/server/config/up.sh b/source/server/config/up.sh
index fd805e2f..0e76842c 100755
--- a/source/server/config/up.sh
+++ b/source/server/config/up.sh
@@ -1,9 +1,10 @@
-#!/bin/bash -Eeu
+#!/usr/bin/env bash
+set -Eeu
 
 readonly PORT="${CYBER_DOJO_DIFFER_PORT}"
 readonly MY_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
-export RUBYOPT='-W2'
+export RUBYOPT='-W2 --enable-frozen-string-literal'
 
 puma \
   --port=${PORT} \
diff --git a/source/server/differ.rb b/source/server/differ.rb
index 93ef3ab4..c5ec8592 100644
--- a/source/server/differ.rb
+++ b/source/server/differ.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'git_differ'
 require_relative 'git_diff_parser'
 
diff --git a/source/server/external/disk_writer.rb b/source/server/external/disk_writer.rb
index f4ec27b3..dde1c380 100644
--- a/source/server/external/disk_writer.rb
+++ b/source/server/external/disk_writer.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 module External
   class DiskWriter
     def write(pathed_filename, content)
diff --git a/source/server/external/gitter.rb b/source/server/external/gitter.rb
index 1bed68a9..a1a22bc3 100644
--- a/source/server/external/gitter.rb
+++ b/source/server/external/gitter.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 module External
   class Gitter
     def initialize(externals)
diff --git a/source/server/external/http.rb b/source/server/external/http.rb
index 3366dead..8dc0255f 100644
--- a/source/server/external/http.rb
+++ b/source/server/external/http.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'net/http'
 
 module External
diff --git a/source/server/external/saver.rb b/source/server/external/saver.rb
index 8db6e274..3b7f976c 100644
--- a/source/server/external/saver.rb
+++ b/source/server/external/saver.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative '../http_json_hash/service'
 
 module External
diff --git a/source/server/external/sheller.rb b/source/server/external/sheller.rb
index fbe5d467..e8fa1565 100644
--- a/source/server/external/sheller.rb
+++ b/source/server/external/sheller.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative '../utf8_clean'
 require 'open3'
 
diff --git a/source/server/externals.rb b/source/server/externals.rb
index e1766412..7cfdbfd9 100644
--- a/source/server/externals.rb
+++ b/source/server/externals.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'external/disk_writer'
 require_relative 'external/gitter'
 require_relative 'external/http'
diff --git a/source/server/git_diff_parse_filenames.rb b/source/server/git_diff_parse_filenames.rb
index 4726adc8..4ae4c126 100644
--- a/source/server/git_diff_parse_filenames.rb
+++ b/source/server/git_diff_parse_filenames.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 module GitDiffParseFilenames
   def parse_old_new_filenames(header)
     old_filename, new_filename = old_new_filenames(header[0])
diff --git a/source/server/git_diff_parser.rb b/source/server/git_diff_parser.rb
index 8448744a..e9d2f5ef 100644
--- a/source/server/git_diff_parser.rb
+++ b/source/server/git_diff_parser.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'git_diff_parse_filenames'
 
 class GitDiffParser
diff --git a/source/server/git_differ.rb b/source/server/git_differ.rb
index 7d9d5d27..65c3c347 100644
--- a/source/server/git_differ.rb
+++ b/source/server/git_differ.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 class GitDiffer
   def initialize(external)
     @external = external
diff --git a/source/server/http_json_hash/requester.rb b/source/server/http_json_hash/requester.rb
index a2a43d81..120b66d6 100644
--- a/source/server/http_json_hash/requester.rb
+++ b/source/server/http_json_hash/requester.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'json'
 require 'uri'
 
diff --git a/source/server/http_json_hash/service.rb b/source/server/http_json_hash/service.rb
index 691b45a6..5b331d81 100644
--- a/source/server/http_json_hash/service.rb
+++ b/source/server/http_json_hash/service.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'requester'
 require_relative 'unpacker'
 
diff --git a/source/server/http_json_hash/service_error.rb b/source/server/http_json_hash/service_error.rb
index ef502f5d..97147bbd 100644
--- a/source/server/http_json_hash/service_error.rb
+++ b/source/server/http_json_hash/service_error.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 module HttpJsonHash
   class ServiceError < RuntimeError
     def initialize(name, path, args, body, message)
diff --git a/source/server/http_json_hash/unpacker.rb b/source/server/http_json_hash/unpacker.rb
index 918d1d7a..bc63206d 100644
--- a/source/server/http_json_hash/unpacker.rb
+++ b/source/server/http_json_hash/unpacker.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'service_error'
 require 'json'
 
diff --git a/source/server/prober.rb b/source/server/prober.rb
index 4afcb497..c25294a7 100644
--- a/source/server/prober.rb
+++ b/source/server/prober.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 class Prober
   def initialize(externals)
     @externals = externals
diff --git a/source/server/silently.rb b/source/server/silently.rb
index c93358f2..ed3e558a 100644
--- a/source/server/silently.rb
+++ b/source/server/silently.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 def silently
   old_stderr = $stderr
   $stderr = StringIO.new
diff --git a/source/server/utf8_clean.rb b/source/server/utf8_clean.rb
index 0960024e..aaae1f5e 100644
--- a/source/server/utf8_clean.rb
+++ b/source/server/utf8_clean.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 module Utf8
   def self.clean(str)
     # force an encoding change - if encoding is already utf-8
diff --git a/test/client/client_test_base.rb b/test/client/client_test_base.rb
index e7957918..0ec56bc4 100755
--- a/test/client/client_test_base.rb
+++ b/test/client/client_test_base.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'lib/id58_test_base'
 require_app 'differ'
 require_app 'saver'
diff --git a/test/client/differ_client_test.rb b/test/client/differ_client_test.rb
index 73da0aae..64cbbefc 100755
--- a/test/client/differ_client_test.rb
+++ b/test/client/differ_client_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'client_test_base'
 require 'cgi'
 
diff --git a/test/client/http_response_unpacker_test.rb b/test/client/http_response_unpacker_test.rb
index 61aee832..5325ff19 100644
--- a/test/client/http_response_unpacker_test.rb
+++ b/test/client/http_response_unpacker_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'client_test_base'
 require_app 'http_json_hash/unpacker'
 require 'ostruct'
diff --git a/test/client/lib/check_metrics.rb b/test/client/lib/check_metrics.rb
index 0a7358dc..ab3185e8 100644
--- a/test/client/lib/check_metrics.rb
+++ b/test/client/lib/check_metrics.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'json'
 
 def coloured(arg)
diff --git a/test/client/lib/coverage.rb b/test/client/lib/coverage.rb
index ba19afa2..c5bbba57 100644
--- a/test/client/lib/coverage.rb
+++ b/test/client/lib/coverage.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'simplecov'
 require_relative 'simplecov_formatter_json'
 
diff --git a/test/client/lib/coverage_metrics_limits.rb b/test/client/lib/coverage_metrics_limits.rb
index 213464d3..d2011cc7 100644
--- a/test/client/lib/coverage_metrics_limits.rb
+++ b/test/client/lib/coverage_metrics_limits.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 def metrics
   [
     [ nil ],
diff --git a/test/client/lib/id58_test_base.rb b/test/client/lib/id58_test_base.rb
index eda9cce5..01ba0f08 100644
--- a/test/client/lib/id58_test_base.rb
+++ b/test/client/lib/id58_test_base.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'English'
 require 'minitest/autorun'
 require 'minitest/reporters'
diff --git a/test/client/lib/run.sh b/test/client/lib/run.sh
index f8daa329..8bb6e878 100755
--- a/test/client/lib/run.sh
+++ b/test/client/lib/run.sh
@@ -15,10 +15,10 @@ require '${MY_DIR}/coverage.rb'
   require file
 }"
 
-export RUBYOPT='-W2'
 mkdir -p "${COVERAGE_ROOT}"
 
 set +e
+export RUBYOPT='-W2 --enable-frozen-string-literal'
 ruby -e "${SCRIPT}" -- ${TEST_ARGS[@]} 2>&1 | tee "${COVERAGE_ROOT}/${TEST_LOG}"
 STATUS=${PIPESTATUS[0]}
 set -e
diff --git a/test/client/lib/simplecov_formatter_json.rb b/test/client/lib/simplecov_formatter_json.rb
index bc9c3536..215dc51e 100644
--- a/test/client/lib/simplecov_formatter_json.rb
+++ b/test/client/lib/simplecov_formatter_json.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'simplecov'
 require 'json'
 
diff --git a/test/client/lib/slim_json_reporter.rb b/test/client/lib/slim_json_reporter.rb
index b18646bd..76f4bdc9 100644
--- a/test/client/lib/slim_json_reporter.rb
+++ b/test/client/lib/slim_json_reporter.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'json'
 require 'minitest/reporters'
 
diff --git a/test/client/lib/test_metrics_limits.rb b/test/client/lib/test_metrics_limits.rb
index 93037538..1c4efd02 100644
--- a/test/client/lib/test_metrics_limits.rb
+++ b/test/client/lib/test_metrics_limits.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 def metrics
   [
     [ nil ],
diff --git a/test/server/diff_summary_test.rb b/test/server/diff_summary_test.rb
index 29880c57..3494f594 100644
--- a/test/server/diff_summary_test.rb
+++ b/test/server/diff_summary_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 
 class DiffSummaryTest < DifferTestBase
diff --git a/test/server/differ_test.rb b/test/server/differ_test.rb
index dc6c8412..1be37edc 100644
--- a/test/server/differ_test.rb
+++ b/test/server/differ_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 
 class DifferTest < DifferTestBase
diff --git a/test/server/differ_test_base.rb b/test/server/differ_test_base.rb
index f07692e4..b6e7dfe7 100755
--- a/test/server/differ_test_base.rb
+++ b/test/server/differ_test_base.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'lib/id58_test_base'
 require_relative 'saver'
 require_app 'externals'
diff --git a/test/server/external_disk_writer_test.rb b/test/server/external_disk_writer_test.rb
index 20b39e4b..dcf085a9 100755
--- a/test/server/external_disk_writer_test.rb
+++ b/test/server/external_disk_writer_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 
 class ExternalDiskWriterTest < DifferTestBase
diff --git a/test/server/external_gitter_test.rb b/test/server/external_gitter_test.rb
index 74804dbd..91a64b52 100755
--- a/test/server/external_gitter_test.rb
+++ b/test/server/external_gitter_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 require_relative 'spy_sheller'
 
diff --git a/test/server/external_sheller_test.rb b/test/server/external_sheller_test.rb
index 50746071..e90c78fd 100755
--- a/test/server/external_sheller_test.rb
+++ b/test/server/external_sheller_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 
 class ExternalShellerTest < DifferTestBase
diff --git a/test/server/externals_test.rb b/test/server/externals_test.rb
index b284713b..47685f75 100755
--- a/test/server/externals_test.rb
+++ b/test/server/externals_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 
 class ExternalsTest < DifferTestBase
diff --git a/test/server/git_diff_parse_filenames_test.rb b/test/server/git_diff_parse_filenames_test.rb
index e8a8fb4d..a1364afa 100644
--- a/test/server/git_diff_parse_filenames_test.rb
+++ b/test/server/git_diff_parse_filenames_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 require_app 'git_diff_parse_filenames'
 
diff --git a/test/server/git_diff_parser_test.rb b/test/server/git_diff_parser_test.rb
index a52af258..4e3d3476 100755
--- a/test/server/git_diff_parser_test.rb
+++ b/test/server/git_diff_parser_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 
 class GitDiffParserTest < DifferTestBase
diff --git a/test/server/http_adapter_stub.rb b/test/server/http_adapter_stub.rb
index cb9a05d3..757077e7 100644
--- a/test/server/http_adapter_stub.rb
+++ b/test/server/http_adapter_stub.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'ostruct'
 
 class HttpAdapterStub
diff --git a/test/server/http_json_hash/http.rb b/test/server/http_json_hash/http.rb
index b76ec154..8a68b1ec 100644
--- a/test/server/http_json_hash/http.rb
+++ b/test/server/http_json_hash/http.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'net/http'
 
 module Test; end
diff --git a/test/server/http_json_hash/requester.rb b/test/server/http_json_hash/requester.rb
index 51274253..da68c78e 100644
--- a/test/server/http_json_hash/requester.rb
+++ b/test/server/http_json_hash/requester.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'http'
 require 'json'
 require 'uri'
diff --git a/test/server/http_json_hash/service.rb b/test/server/http_json_hash/service.rb
index c968a041..b1bdcc85 100644
--- a/test/server/http_json_hash/service.rb
+++ b/test/server/http_json_hash/service.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'requester'
 require_relative 'unpacker'
 
diff --git a/test/server/http_json_hash/unpacker.rb b/test/server/http_json_hash/unpacker.rb
index 6596af3e..60532e9e 100644
--- a/test/server/http_json_hash/unpacker.rb
+++ b/test/server/http_json_hash/unpacker.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'json'
 
 module Test
diff --git a/test/server/http_proxy_response_test.rb b/test/server/http_proxy_response_test.rb
index c76af862..fb5dbb23 100644
--- a/test/server/http_proxy_response_test.rb
+++ b/test/server/http_proxy_response_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 require_relative 'http_adapter_stub'
 
diff --git a/test/server/lib/check_metrics.rb b/test/server/lib/check_metrics.rb
index 0a7358dc..ab3185e8 100644
--- a/test/server/lib/check_metrics.rb
+++ b/test/server/lib/check_metrics.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'json'
 
 def coloured(arg)
diff --git a/test/server/lib/coverage.rb b/test/server/lib/coverage.rb
index b2f37ab5..68ab75e5 100644
--- a/test/server/lib/coverage.rb
+++ b/test/server/lib/coverage.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'simplecov'
 require_relative 'simplecov_formatter_json'
 
diff --git a/test/server/lib/coverage_metrics_limits.rb b/test/server/lib/coverage_metrics_limits.rb
index db783255..e366e72d 100644
--- a/test/server/lib/coverage_metrics_limits.rb
+++ b/test/server/lib/coverage_metrics_limits.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 def metrics
   [
     [ nil ],
diff --git a/test/server/lib/id58_test_base.rb b/test/server/lib/id58_test_base.rb
index 1ef8a480..01ba0f08 100644
--- a/test/server/lib/id58_test_base.rb
+++ b/test/server/lib/id58_test_base.rb
@@ -1,4 +1,3 @@
-# frozen_string_literal: true
 require 'English'
 require 'minitest/autorun'
 require 'minitest/reporters'
diff --git a/test/server/lib/run.sh b/test/server/lib/run.sh
index f8daa329..8bb6e878 100755
--- a/test/server/lib/run.sh
+++ b/test/server/lib/run.sh
@@ -15,10 +15,10 @@ require '${MY_DIR}/coverage.rb'
   require file
 }"
 
-export RUBYOPT='-W2'
 mkdir -p "${COVERAGE_ROOT}"
 
 set +e
+export RUBYOPT='-W2 --enable-frozen-string-literal'
 ruby -e "${SCRIPT}" -- ${TEST_ARGS[@]} 2>&1 | tee "${COVERAGE_ROOT}/${TEST_LOG}"
 STATUS=${PIPESTATUS[0]}
 set -e
diff --git a/test/server/lib/simplecov_formatter_json.rb b/test/server/lib/simplecov_formatter_json.rb
index bc9c3536..215dc51e 100644
--- a/test/server/lib/simplecov_formatter_json.rb
+++ b/test/server/lib/simplecov_formatter_json.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'simplecov'
 require 'json'
 
diff --git a/test/server/lib/slim_json_reporter.rb b/test/server/lib/slim_json_reporter.rb
index b18646bd..76f4bdc9 100644
--- a/test/server/lib/slim_json_reporter.rb
+++ b/test/server/lib/slim_json_reporter.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require 'json'
 require 'minitest/reporters'
 
diff --git a/test/server/lib/test_metrics_limits.rb b/test/server/lib/test_metrics_limits.rb
index c9eb0dba..c2472bb2 100644
--- a/test/server/lib/test_metrics_limits.rb
+++ b/test/server/lib/test_metrics_limits.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 def metrics
   [
     [ nil ],
diff --git a/test/server/prober_test.rb b/test/server/prober_test.rb
index ead89ee0..2c3fa3b1 100644
--- a/test/server/prober_test.rb
+++ b/test/server/prober_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 require 'ostruct'
 
diff --git a/test/server/raising_disk_writer.rb b/test/server/raising_disk_writer.rb
index 35952fe6..913eb64a 100644
--- a/test/server/raising_disk_writer.rb
+++ b/test/server/raising_disk_writer.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 class RaisingDiskWriter
   attr_reader :pathed_filename
 
diff --git a/test/server/saver.rb b/test/server/saver.rb
index de4a13d1..08f8fc7d 100644
--- a/test/server/saver.rb
+++ b/test/server/saver.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'http_json_hash/service'
 
 module Test
diff --git a/test/server/spy_sheller.rb b/test/server/spy_sheller.rb
index 00063bc9..7f7efebc 100644
--- a/test/server/spy_sheller.rb
+++ b/test/server/spy_sheller.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 class SpySheller
   def initialize
     @spied = []
diff --git a/test/server/utf8_clean_test.rb b/test/server/utf8_clean_test.rb
index 26092e7d..a90d5c91 100755
--- a/test/server/utf8_clean_test.rb
+++ b/test/server/utf8_clean_test.rb
@@ -1,5 +1,3 @@
-# frozen_string_literal: true
-
 require_relative 'differ_test_base'
 require_app 'utf8_clean'
 

From 29b3569ddab51083e052116d01dc7025962b23bd Mon Sep 17 00:00:00 2001
From: JonJagger <jon@kosli.com>
Date: Thu, 12 Feb 2026 12:39:59 +0000
Subject: [PATCH 2/4] Update rubocop config

---
 .rubocop.yml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/.rubocop.yml b/.rubocop.yml
index 93b33e07..71f7cba2 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -51,6 +51,11 @@ Style/FetchEnvVar:
   Exclude:
     - source/server/app_base.rb
 
+Style/FrozenStringLiteralComment:
+  Exclude:
+    - source/**/*
+    - test/**/*
+
 Style/HashConversion:
   Exclude:
     - source/server/app_base.rb

From b04373b6bb8cbab093ee64f903b5e017465b336b Mon Sep 17 00:00:00 2001
From: JonJagger <jon@kosli.com>
Date: Thu, 12 Feb 2026 12:40:28 +0000
Subject: [PATCH 3/4] Update rubocop config

---
 .rubocop.yml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/.rubocop.yml b/.rubocop.yml
index 71f7cba2..b89318cd 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -54,7 +54,6 @@ Style/FetchEnvVar:
 Style/FrozenStringLiteralComment:
   Exclude:
     - source/**/*
-    - test/**/*
 
 Style/HashConversion:
   Exclude:

From 5f8eca36622af759e27bb458d705d75f12108682 Mon Sep 17 00:00:00 2001
From: JonJagger <jon@kosli.com>
Date: Fri, 13 Feb 2026 09:53:19 +0000
Subject: [PATCH 4/4] Remove snyk-container-scan from main workflow

---
 .github/workflows/main.yml  | 45 -------------------------------------
 .github/workflows/readme.md |  5 +++--
 .kosli.yml                  |  2 --
 3 files changed, 3 insertions(+), 49 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 79bf18b3..4f3db271 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -286,50 +286,6 @@ jobs:
             --type=coverage-metrics
 
 
-  snyk-container-scan:
-    runs-on: ubuntu-latest
-    needs: [build-image]
-    env:
-      IMAGE_NAME:        ${{ needs.build-image.outputs.tagged_image_name }}
-      KOSLI_FINGERPRINT: ${{ needs.build-image.outputs.digest }}
-      SARIF_FILENAME:    snyk.container.scan.json
-    steps:
-      - name: Download docker image
-        uses: cyber-dojo/download-artifact@main
-        with:
-          image_digest: ${{ needs.build-image.outputs.digest }}
-
-      - uses: actions/checkout@v4
-        with:
-          fetch-depth: 1
-
-      - name: Setup Snyk
-        uses: snyk/actions/setup@master
-
-      - name: Run Snyk container scan
-        env:
-          SNYK_TOKEN: ${{ secrets.SNYK_TOKEN }}
-        run:
-          snyk container test ${IMAGE_NAME}
-            --policy-path=.snyk
-            --sarif
-            --sarif-file-output="${SARIF_FILENAME}"
-
-      - name: Setup Kosli CLI
-        if: ${{ github.ref == 'refs/heads/main' && (success() || failure()) }}
-        uses: kosli-dev/setup-cli-action@v2
-        with:
-          version: ${{ vars.KOSLI_CLI_VERSION }}
-
-      - name: Attest evidence to Kosli
-        if: ${{ github.ref == 'refs/heads/main' && (success() || failure()) }}
-        run:
-          kosli attest snyk
-            --attachments=.snyk
-            --name=differ.snyk-container-scan
-            --scan-results="${SARIF_FILENAME}"
-
-
   sonarcloud-scan:
     runs-on: ubuntu-latest
     needs: [build-image]
@@ -361,7 +317,6 @@ jobs:
       - rubocop-lint
       - unit-tests
       - integration-tests
-      - snyk-container-scan
       - snyk-code-scan
       - sonarcloud-scan
     env:
diff --git a/.github/workflows/readme.md b/.github/workflows/readme.md
index e5b9c686..5c7783bd 100644
--- a/.github/workflows/readme.md
+++ b/.github/workflows/readme.md
@@ -3,8 +3,6 @@
 
 ## main.yml 
 main.yml runs when there is a pushed commit.
-Reports to https://app.kosli.com  
-The workflow to look in if you want to learn about [Kosli](https://kosli.com).
 The main structure in this workflow is:
 - The build-image job calls a [reusable-workflow](https://github.com/cyber-dojo/reusable-actions-workflows) which:
   - builds the image
@@ -16,6 +14,9 @@ The main structure in this workflow is:
   - They load it from the Github Action cache using [cyber-dojo/download-artifact@main](https://github.com/cyber-dojo/download-artifact)
   - The kosli-attest commands use the fingerprint returned from the build-image job
 
+Reports compliance to https://app.kosli.com  
+The workflow to look in if you want to learn about [Kosli](https://app.kosli.com/cyber-dojo/flows/differ-ci/trails/).
+
 
 ## deploy-manually-to-aws-beta.yml 
 Deliberately run a non-compliant (but functional) artifact to https://beta.cyber-dojo.org for Kosli demo purposes.  
diff --git a/.kosli.yml b/.kosli.yml
index 2d6aae6c..9be5a196 100644
--- a/.kosli.yml
+++ b/.kosli.yml
@@ -9,8 +9,6 @@ trail:
       attestations:
         - name: rubocop-lint
           type: junit
-        - name: snyk-container-scan
-          type: snyk
         - name: snyk-code-scan
           type: snyk
         - name: unit-test