[ruby/json] Reject incompatible RFC 8785 generation options

https://github.com/ruby/json/commit/49e8df0e16

ext/json/generator/generator.c

@@ -1307,10 +1307,28 @@ static void generate_json_no_fallback(FBuffer *buffer, struct generate_json_data
     generate_json_general(buffer, data, obj, false);
 }
 
+static void validate_rfc8785(JSON_Generator_State *state)
+{
+    if (!state->rfc8785) return;
+
+    const char *option = state->indent ? "indent" :
+        state->space ? "space" :
+        state->space_before ? "space_before" :
+        state->object_nl ? "object_nl" :
+        state->array_nl ? "array_nl" :
+        state->ascii_only ? "ascii_only" :
+        state->script_safe ? "script_safe" :
+        state->allow_nan ? "allow_nan" : NULL;
+    if (option) {
+        rb_raise(rb_eArgError, "%s cannot be used with rfc8785", option);
+    }
+}
+
 static VALUE generate_json_try(VALUE d)
 {
     struct generate_json_data *data = (struct generate_json_data *)d;
 
+    validate_rfc8785(data->state);
     data->func(data->buffer, data, data->obj);
 
     return fbuffer_finalize(data->buffer);
@@ -1990,6 +2008,7 @@ static void configure_state(JSON_Generator_State *state, VALUE vstate, VALUE con
     rb_hash_foreach(config, configure_state_i, (VALUE)&data);
 
     raise_argument_error_on_unknown_keywords(data.unknown_keywords);
+    validate_rfc8785(state);
 }
 
 static VALUE cState_configure(VALUE self, VALUE opts)

ext/json/lib/json.rb

@@ -418,6 +418,10 @@ require 'json/common'
 #   as defined in RFC8785.
 #   Integers are converted to Float before formatting and may be rounded.
 #   Integers outside the finite Float range raise JSON::GeneratorError.
+#   Nonempty +indent+, +space+, +space_before+, +object_nl+, or +array_nl+,
+#   and enabled +ascii_only+, +script_safe+, or +allow_nan+ raise ArgumentError.
+#   JSON.dump defaults +allow_nan+ to +false+ when +rfc8785+ is enabled.
+#   JSON::Fragment contents are inserted as is; the caller must ensure they are canonical.
 #
 # In this example, +obj+ is used first to generate the shortest
 # \JSON data (no whitespace), then again with all formatting options

ext/json/lib/json/common.rb

@@ -763,7 +763,7 @@ module JSON
     end
 
     opts = {
-      allow_nan: true,
+      allow_nan: !(kwargs && kwargs[:rfc8785]),
     }
     opts[:max_nesting] = _deprecated_limit if _deprecated_limit
     opts.merge!(kwargs) if kwargs

test/json/json_generator_test.rb

@@ -1325,6 +1325,62 @@ class JSONGeneratorTest < Test::Unit::TestCase
     end
   end
 
+  {
+    indent: ' ', space: ' ', space_before: ' ', object_nl: "\n", array_nl: "\n",
+    ascii_only: true, script_safe: true, allow_nan: true,
+  }.each do |option, value|
+    define_method("test_rfc8785_rejects_#{option}") do
+      options = { rfc8785: true, option => value }
+      error = assert_raise(ArgumentError) { JSON.generate({ 'a' => [1] }, options) }
+      assert_equal "#{option} cannot be used with rfc8785", error.message
+      assert_raise(ArgumentError) { JSON.generate(nil, options.to_a.reverse.to_h) }
+      assert_raise(ArgumentError) { [1].to_json(options) }
+      assert_raise(ArgumentError) { { 'a' => 1 }.to_json(options) }
+      assert_raise(ArgumentError) { JSON::Coder.new(**options).dump([1]) }
+
+      state = JSON::State.new(option => value)
+      state.rfc8785 = true
+      io = StringIO.new
+      assert_raise(ArgumentError) { state.generate([1], io) }
+      assert_equal '', io.string
+      assert_raise(ArgumentError) { [1].to_json(state) }
+      assert_equal 0, state.depth
+      assert_raise(ArgumentError) { state.freeze.generate([1]) }
+    end
+  end
+
+  def test_rfc8785_accepts_disabled_options
+    options = { rfc8785: true, indent: '', space: '', space_before: '',
+                object_nl: '', array_nl: '', ascii_only: false,
+                script_safe: false, allow_nan: false }
+    assert_equal '["é/",1]', JSON.generate(['é/', 1], options)
+  end
+
+  def test_rfc8785_rejects_pretty_generation
+    assert_raise(ArgumentError) { JSON.pretty_generate({ 'a' => 1 }, rfc8785: true) }
+  end
+
+  def test_rfc8785_dump_disables_allow_nan_by_default
+    assert_equal '[1]', JSON.dump([1], rfc8785: true)
+    [Float::NAN, Float::INFINITY, -Float::INFINITY].each do |number|
+      assert_raise(JSON::GeneratorError) { JSON.dump([number], rfc8785: true) }
+    end
+    assert_raise(ArgumentError) { JSON.dump([1], rfc8785: true, allow_nan: true) }
+  end
+
+  def test_rfc8785_fragments
+    fragment = JSON::Fragment.new('[1,2]')
+    assert_rfc8785 '[1,2]', fragment
+    assert_rfc8785 '[[1,2]]', [fragment]
+    assert_rfc8785 '{"a":[1,2]}', { 'a' => fragment }
+    assert_equal '[[1,2]]', JSON.generate([fragment], rfc8785: true, max_nesting: false)
+    assert_equal '[1,2]', JSON::Coder.new(rfc8785: true).dump(fragment)
+    assert_equal '[1,2]', fragment.to_json(rfc8785: true)
+
+    # Fragment contents are the caller's responsibility and are inserted as is.
+    assert_rfc8785 '[1, 2]', JSON::Fragment.new('[1, 2]')
+  end
+
   def test_rfc8785_numbers
     assert_rfc8785 '-9007199254740992', -9007199254740992
     assert_rfc8785 '0', 0