Lower minimum Ruby version to 2.5 and make JSON duplicate key detection a runtime feature check instead of a hard dependency on json >= 2.13.0

Author: ydah

.github/workflows/test.yml

@@ -33,6 +33,8 @@ jobs:
         os:
           - ubuntu-latest
         ruby:
+          - "2.5"
+          - "2.6"
           - "2.7"
           - "3.0"
           - "3.1"

.rubocop.yml

@@ -1,5 +1,5 @@
 AllCops:
-  TargetRubyVersion: 2.7
+  TargetRubyVersion: 2.5
   NewCops: enable
   SuggestExtensions: false
   Exclude:

lib/jwt/json.rb

@@ -28,12 +28,26 @@ def generate(data)
       #   JWT::JSON.parse('{"a":1,"a":2}', allow_duplicate_keys: false)
       #   # => raises JWT::DuplicateKeyError
       def parse(data, allow_duplicate_keys: true)
-        ::JSON.parse(data, allow_duplicate_key: allow_duplicate_keys)
+        return ::JSON.parse(data) if allow_duplicate_keys
+
+        if supports_duplicate_key_detection?
+          ::JSON.parse(data, allow_duplicate_key: false)
+        else
+          ::JSON.parse(data)
+        end
       rescue ::JSON::ParserError => e
         raise JWT::DuplicateKeyError, e.message if e.message.include?('duplicate key')
 
         raise
       end
+
+      private
+
+      def supports_duplicate_key_detection?
+        return @supports_duplicate_key_detection if defined?(@supports_duplicate_key_detection)
+
+        @supports_duplicate_key_detection = Gem::Version.new(::JSON::VERSION) >= Gem::Version.new('2.13.0')
+      end
     end
   end
 end

ruby-jwt.gemspec

@@ -15,7 +15,7 @@ Gem::Specification.new do |spec|
   spec.description = 'A pure ruby implementation of the RFC 7519 OAuth JSON Web Token (JWT) standard.'
   spec.homepage = 'https://github.com/jwt/ruby-jwt'
   spec.license = 'MIT'
-  spec.required_ruby_version = '>= 2.7'
+  spec.required_ruby_version = '>= 2.5'
   spec.metadata = {
     'bug_tracker_uri' => 'https://github.com/jwt/ruby-jwt/issues',
     'changelog_uri' => "https://github.com/jwt/ruby-jwt/blob/v#{JWT.gem_version}/CHANGELOG.md",
@@ -32,7 +32,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = %w[lib]
 
   spec.add_dependency 'base64'
-  spec.add_dependency 'json', '>= 2.13.0'
+  spec.add_dependency 'json'
 
   spec.add_development_dependency 'appraisal'
   spec.add_development_dependency 'bundler'