Reset all per-parse state in JSON::ResumableParser#clear

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: 2 people

ext/json/ext/parser/parser.c

@@ -2487,6 +2487,9 @@ static VALUE cResumableParser_clear(VALUE self)
     parser->frames.head = 0;
     parser->value_stack.head = 0;
     parser->state.name_cache.length = 0;
+    parser->state.current_nesting = 0;
+    parser->state.in_array = 1;
+    parser->state.emitted_deprecations = 0;
     parser->state.start = parser->state.cursor = parser->state.end = NULL;
     return self;
 }

test/json/resumable_parser_test.rb

@@ -63,6 +63,20 @@ def test_parse_with_empty_buffer_keeps_parser_usable
     assert_equal [4], @parser.value
   end
 
+  def test_clear_resets_nesting_depth
+    # An unfinished document leaks a nesting level; #clear must reset it so a later shallow
+    # document is not rejected with a spurious NestingError.
+    parser = new_parser(max_nesting: 10)
+    10.times do
+      parser << '[1' # opens an array that is never closed before clear
+      parser.parse
+      parser.clear
+    end
+    parser << '[1]'
+    assert parser.parse
+    assert_equal [1], parser.value
+  end
+
   def test_parse_document_direct
     @parser << '[true]'
     assert_equal true, @parser.parse