Do not update `load_defaults` version when running `app:update` (#31951)

Incompatible settings are included in the settings set by `load_defaults`.
So, I think that target version should be updated by a user when becomes
available, and should not be updated with `app:update`.

1 files changed, 15 insertions, 0 deletions

diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index 14246edf38..23e6371a79 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -219,6 +219,8 @@ class AppGeneratorTest < Rails::Generators::TestCase
     run_generator [app_root]
     output = nil
 
+    assert_file "#{app_root}/config/application.rb", /\s+config\.load_defaults #{Rails::VERSION::STRING.to_f}/
+
     Dir.chdir(app_root) do
       output = `./bin/rails r "puts Rails.application.config.assets.unknown_asset_fallback"`
     end
@@ -367,6 +369,19 @@ class AppGeneratorTest < Rails::Generators::TestCase
     end
   end
 
+  def test_app_update_does_not_change_config_target_version
+    run_generator
+
+    FileUtils.cd(destination_root) do
+      config = "config/application.rb"
+      content = File.read(config)
+      File.write(config, content.gsub(/config\.load_defaults #{Rails::VERSION::STRING.to_f}/, "config.load_defaults 5.1"))
+      quietly { system("bin/rails app:update") }
+    end
+
+    assert_file "config/application.rb", /\s+config\.load_defaults 5\.1/
+  end
+
   def test_application_names_are_not_singularized
     run_generator [File.join(destination_root, "hats")]
     assert_file "hats/config/environment.rb", /Rails\.application\.initialize!/