From d5609bed29c463b991584ed0499dd158d65e8bf2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89tienne=20Barri=C3=A9?= <etienne.barrie@gmail.com>
Date: Mon, 10 Feb 2025 11:09:17 +0100
Subject: [PATCH] Use JSON::Coder when available

---
 .../lib/active_support/json/encoding.rb       | 46 ++++++++++++++++++-
 activesupport/test/json/encoding_test.rb      | 13 ++++++
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/activesupport/lib/active_support/json/encoding.rb b/activesupport/lib/active_support/json/encoding.rb
index 2fe140270d54..1fafaac44346 100644
--- a/activesupport/lib/active_support/json/encoding.rb
+++ b/activesupport/lib/active_support/json/encoding.rb
@@ -97,6 +97,45 @@ def stringify(jsonified)
           end
       end
 
+      if defined?(::JSON::Coder)
+        class JSONGemCoderEncoder # :nodoc:
+          JSON_NATIVE_TYPES = [Hash, Array, Float, String, Symbol, Integer, NilClass, TrueClass, FalseClass].freeze
+          CODER = ::JSON::Coder.new do |value|
+            json_value = value.as_json
+            # Handle objects returning self from as_json
+            if json_value.equal?(value)
+              next ::JSON::Fragment.new(value.to_json)
+            end
+            # Handle objects not returning JSON-native types from as_json
+            until JSON_NATIVE_TYPES.include?(json_value.class)
+              json_value = json_value.as_json
+            end
+            json_value
+          end
+
+
+          def initialize(options = nil)
+            @options = options ? options.dup.freeze : {}.freeze
+          end
+
+          # Encode the given object into a JSON string
+          def encode(value)
+            value = value.as_json(@options) unless @options.empty?
+
+            json = CODER.dump(value)
+
+            if @options.fetch(:escape_html_entities, Encoding.escape_html_entities_in_json)
+              json.gsub!(">", '\u003e')
+              json.gsub!("<", '\u003c')
+              json.gsub!("&", '\u0026')
+            end
+            json.gsub!("\u2028", '\u2028')
+            json.gsub!("\u2029", '\u2029')
+            json
+          end
+        end
+      end
+
       class << self
         # If true, use ISO 8601 format for dates and times. Otherwise, fall back
         # to the Active Support legacy format.
@@ -126,7 +165,12 @@ def encode_without_options(value) # :nodoc:
 
       self.use_standard_json_time_format = true
       self.escape_html_entities_in_json  = true
-      self.json_encoder = JSONGemEncoder
+      self.json_encoder =
+        if defined?(::JSON::Coder)
+          JSONGemCoderEncoder
+        else
+          JSONGemEncoder
+        end
       self.time_precision = 3
     end
   end
diff --git a/activesupport/test/json/encoding_test.rb b/activesupport/test/json/encoding_test.rb
index 6bffa7ff2275..d1938e28696b 100644
--- a/activesupport/test/json/encoding_test.rb
+++ b/activesupport/test/json/encoding_test.rb
@@ -504,3 +504,16 @@ def with_time_precision(value)
       ActiveSupport::JSON::Encoding.time_precision = old_value
     end
 end
+
+if defined?(::JSON::Coder)
+  class OldJSONEncodingTest < TestJSONEncoding
+    setup do
+      @json_encoder = ActiveSupport::JSON::Encoding.json_encoder
+      ActiveSupport::JSON::Encoding.json_encoder = ActiveSupport::JSON::Encoding::JSONGemEncoder
+    end
+
+    teardown do
+      ActiveSupport::JSON::Encoding.json_encoder = @json_encoder
+    end
+  end
+end