Gem::YAMLSerializer may not roundtrip metadata

### Describe the problem as clearly as you can We can specify any valid UTF-8 128 bytes key and 1024 bytes value as metadata: https://guides.rubygems.org/specification-reference/#metadata For example, all of the following cases are valid: * `spec.metadata["have space"] = "space value"` * `spec.metadata["have:colon"] = "colon:value"` * `spec.metadata["\"double_quoted\""] = "\"quoted_value\""` * `spec.metadata["'single_quoted'"] = "'quoted_value'"` These quoted patterns can't be roundtrip with The current `Gem::YAMLSerializer`: ```diff diff --git a/test/rubygems/test_gem_safe_yaml.rb b/test/rubygems/test_gem_safe_yaml.rb index d6fef1d7de..4aa5dbff72 100644 --- a/test/rubygems/test_gem_safe_yaml.rb +++ b/test/rubygems/test_gem_safe_yaml.rb @@ -648,6 +648,10 @@ def test_roundtrip_specification_with_metadata "source_code_uri" => "https://github.com/example/metadata-test", "bug_tracker_uri" => "https://github.com/example/metadata-test/issues", "allowed_push_host" => "https://rubygems.org", + "\"double_quoted\"" => "\"quoted_value\"", + "'single_quoted'" => "'quoted_value'", + "have:colon" => "value:colon", + "have space" => "value space", } end @@ -655,12 +659,17 @@ def test_roundtrip_specification_with_metadata loaded = Gem::SafeYAML.safe_load(yaml) assert_kind_of Gem::Specification, loaded - assert_kind_of Hash, loaded.metadata - assert_equal 4, loaded.metadata.size - assert_equal "https://example.com/CHANGELOG.md", loaded.metadata["changelog_uri"] - assert_equal "https://github.com/example/metadata-test", loaded.metadata["source_code_uri"] - assert_equal "https://github.com/example/metadata-test/issues", loaded.metadata["bug_tracker_uri"] - assert_equal "https://rubygems.org", loaded.metadata["allowed_push_host"] + expected_metadata = { + "changelog_uri" => "https://example.com/CHANGELOG.md", + "source_code_uri" => "https://github.com/example/metadata-test", + "bug_tracker_uri" => "https://github.com/example/metadata-test/issues", + "allowed_push_host" => "https://rubygems.org", + "\"double_quoted\"" => "\"quoted_value\"", + "'single_quoted'" => "'quoted_value'", + "have:colon" => "value:colon", + "have space" => "value space", + } + assert_equal expected_metadata, loaded.metadata end def test_roundtrip_version ``` ```text Failure: test_roundtrip_specification_with_metadata(TestGemSafeYAML) test/rubygems/test_gem_safe_yaml.rb:673:in 'TestGemSafeYAML#test_roundtrip_specification_with_metadata' <{"\"double_quoted\""=>"\"quoted_value\"", "'single_quoted'"=>"'quoted_value'", "allowed_push_host"=>"https://rubygems.org", "bug_tracker_uri"=>"https://github.com/example/metadata-test/issues", "changelog_uri"=>"https://example.com/CHANGELOG.md", "have space"=>"value space", "have:colon"=>"value:colon", "source_code_uri"=>"https://github.com/example/metadata-test"}> expected but was <{"\"double_quoted\""=>"quoted_value", "'single_quoted'"=>"quoted_value", "allowed_push_host"=>"https://rubygems.org", "bug_tracker_uri"=>"https://github.com/example/metadata-test/issues", "changelog_uri"=>"https://example.com/CHANGELOG.md", "have space"=>"value space", "have:colon"=>"value:colon", "source_code_uri"=>"https://github.com/example/metadata-test"}> diff: ? {"\"double_quoted\""=>"\"quoted_value\"", ? "'single_quoted'"=>"'quoted_value'", "allowed_push_host"=>"https://rubygems.org", "bug_tracker_uri"=>"https://github.com/example/metadata-test/issues", "changelog_uri"=>"https://example.com/CHANGELOG.md", "have space"=>"value space", "have:colon"=>"value:colon", "source_code_uri"=>"https://github.com/example/metadata-test"} ``` (Quotations (`"` and `'`) are missing for `quoted_value`.) ### Did you try upgrading RubyGems? Yes. ### Post steps to reproduce the problem Use the above diff. ### Which command did you run? None. ### What were you expecting to happen? Quoted values can be roundtrip. ### What actually happened? Quotations in value are missing. ### Run `gem env` and paste the output below ```text RubyGems Environment: - RUBYGEMS VERSION: 4.1.0.dev - RUBY VERSION: 4.1.0 (2026-05-02 patchlevel -1) [x86_64-linux] - INSTALLATION DIRECTORY: /var/tmp/local/lib/ruby/gems/4.1.0+1 - USER INSTALLATION DIRECTORY: /home/kou/.gem/ruby/4.1.0+1 - CREDENTIALS FILE: /home/kou/.gem/credentials - RUBYGEMS PREFIX: /home/kou/work/ruby/rubygems - RUBY EXECUTABLE: /var/tmp/local/bin/ruby - GIT EXECUTABLE: /bin/git - EXECUTABLE DIRECTORY: /var/tmp/local/bin - SPEC CACHE DIRECTORY: /home/kou/.cache/gem/specs - SYSTEM CONFIGURATION DIRECTORY: /var/tmp/local/etc - RUBYGEMS PLATFORMS: - ruby - x86_64-linux - GEM PATHS: - /var/tmp/local/lib/ruby/gems/4.1.0+1 - /home/kou/.gem/ruby/4.1.0+1 - GEM CONFIGURATION: - :update_sources => true - :verbose => true - :backtrace => true - :bulk_threshold => 1000 - REMOTE SOURCES: - https://rubygems.org/ - SHELL PATH: - /var/tmp/local/bin - /bin - /usr/local/bin - /usr/bin - /usr/games ```