Reproduce C ext behavior of ignoring mutated depth in arrays

Author: etiennebarrie

java/src/json/ext/Generator.java

@@ -462,10 +462,10 @@ static void generateArray(ThreadContext context, Session session, RubyArray<IRub
             generateFor(context, session, element, buffer);
         }
 
-        int oldDepth = state.decreaseDepth();
+        state.depth = --depth;
         if (!arrayNLEmpty) {
             buffer.write(arrayNLBytes, arrayNLBegin, arrayNLSize);
-            Utils.repeatWrite(buffer, indentUnit, oldDepth);
+            Utils.repeatWrite(buffer, indentUnit, depth);
         }
 
         buffer.write((byte) ']');

java/src/json/ext/GeneratorState.java

@@ -107,7 +107,7 @@ public class GeneratorState extends RubyObject {
     /**
      * The current depth (inside a #to_json call)
      */
-    private int depth = 0;
+    protected int depth = 0;
 
     static final ObjectAllocator ALLOCATOR = GeneratorState::new;
 

lib/json/truffle_ruby/generator.rb

@@ -626,7 +626,7 @@ def json_transform(state)
               end
               first = false
             }
-            depth = state.depth -= 1
+            state.depth = depth -= 1
             result << state.array_nl
             result << state.indent * depth if indent
             result << ']'

test/json/json_generator_test.rb

@@ -329,7 +329,6 @@ def obj.to_json(state)
         "#{state.indent * state.depth}\"foo\":#{state.space}1#{state.object_nl}"\
         "#{state.indent * (state.depth - 1)}}"
     end
-    indent = "  " * 2 if RUBY_ENGINE != "ruby"
     assert_equal <<~JSON.chomp, JSON.pretty_generate([obj] * 2)
       [
         {
@@ -338,11 +337,14 @@ def obj.to_json(state)
         {
             "foo": 1
           }
-      #{indent}]
+      ]
     JSON
     state = JSON::State.new(object_nl: "\n", array_nl: "\n", space: " ", indent: "  ")
     state.generate(obj)
-    assert_equal 1, state.depth
+    assert_equal 1, state.depth # FIXME
+    state.depth = 0
+    state.generate([obj])
+    assert_equal 0, state.depth
   end
 
   def test_depth