Fix spurious JSON event emitted by JsonpUtils.copy() (#597)

Author: swallez

java-client/src/main/java/co/elastic/clients/json/JsonpUtils.java

@@ -175,7 +175,6 @@ public static void copy(JsonParser parser, JsonGenerator generator, JsonParser.E
 
             case START_ARRAY:
                 generator.writeStartArray();
-                generator.writeStartObject();
                 while ((event = parser.next()) != Event.END_ARRAY) {
                     copy(parser, generator, event);
                 }

java-client/src/test/java/co/elastic/clients/json/JsonpUtilsTest.java

@@ -25,13 +25,14 @@
 import co.elastic.clients.elasticsearch.security.IndicesPrivileges;
 import co.elastic.clients.elasticsearch.security.RoleTemplateScript;
 import co.elastic.clients.elasticsearch.security.UserIndicesPrivileges;
-import co.elastic.clients.json.JsonpUtils;
 import co.elastic.clients.util.AllowForbiddenApis;
 import jakarta.json.JsonException;
 import jakarta.json.spi.JsonProvider;
 import jakarta.json.stream.JsonGenerator;
+import jakarta.json.stream.JsonParser;
 import org.junit.jupiter.api.Test;
 
+import java.io.StringReader;
 import java.io.StringWriter;
 import java.net.URL;
 import java.util.Collections;
@@ -209,6 +210,47 @@ public void testJsonString() {
         }
     }
 
+    @Test
+    public void testCopy() {
+        // Tests round-tripping a json document that contains all event types and various kinds of nesting
+
+        String json = "{\n" +
+            "  \"p1\": \"str1\",\n" +
+            "  \"p2\": 42,\n" +
+            "  \"p3\": [\"str31\", \"str32\"],\n" +
+            "  \"p4\": {\n" +
+            "    \"p41\": \"str41\",\n" +
+            "    \"p42\": [\"str421\", \"str422\"],\n" +
+            "    \"p43\": {\n" +
+            "      \"p431\": \"str431\"\n" +
+            "    },\n" +
+            "    \"p44\": true,\n" +
+            "    \"p45\": false,\n" +
+            "    \"p46\": 3.14\n" +
+            "  },\n" +
+            "  \"p5\": [{\n" +
+            "    \"p51\": {\n" +
+            "      \"p511\": \"str511\"\n" +
+            "    }\n" +
+            "  }],\n" +
+            "  \"p6\": null\n" +
+            "}\n";
+
+        json = normalizeIndent(json);
+
+        JsonProvider provider = JsonpUtils.provider();
+
+        JsonParser parser = provider.createParser(new StringReader(json));
+        StringWriter sw = new StringWriter();
+        JsonGenerator generator = provider.createGenerator(sw);
+
+        JsonpUtils.copy(parser, generator);
+        parser.close();
+        generator.close();
+
+        assertEquals(json, sw.toString());
+    }
+
     private static String orNullHelper(Consumer<JsonGenerator> c) {
         StringWriter sw = new StringWriter();
         JsonGenerator generator = JsonpUtils.provider().createGenerator(sw);
@@ -221,4 +263,69 @@ private static String orNullHelper(Consumer<JsonGenerator> c) {
 
         return sw.toString();
     }
+
+    /**
+     * Normalizes the whitespace and indentation of a JSON string by parsing it and copying it to a string generator.
+     */
+    private static String normalizeIndent(String json) {
+        JsonParser parser = JsonpUtils.provider().createParser(new StringReader(json));
+        StringWriter sw = new StringWriter();
+        JsonGenerator generator = JsonpUtils.provider().createGenerator(sw);
+
+        copyAll(parser, generator);
+
+        parser.close();
+        generator.close();
+        return sw.toString();
+    }
+
+    private static void copyAll(JsonParser parser, JsonGenerator generator) {
+        while(parser.hasNext()) {
+            switch (parser.next()) {
+                case START_OBJECT:
+                    generator.writeStartObject();
+                    break;
+
+                case END_OBJECT:
+                    generator.writeEnd();
+                    break;
+
+                case START_ARRAY:
+                    generator.writeStartArray();
+                    break;
+
+                case END_ARRAY:
+                    generator.writeEnd();
+                    break;
+
+                case KEY_NAME:
+                    generator.writeKey(parser.getString());
+                    break;
+
+                case VALUE_STRING:
+                    generator.write(parser.getString());
+                    break;
+
+                case VALUE_NULL:
+                    generator.writeNull();
+                    break;
+
+                case VALUE_TRUE:
+                    generator.write(true);
+                    break;
+
+                case VALUE_FALSE:
+                    generator.write(false);
+                    break;
+
+                case VALUE_NUMBER:
+                    if (parser.isIntegralNumber()) {
+                        generator.write(parser.getLong());
+                    } else {
+                        generator.write(parser.getBigDecimal());
+                    }
+                    break;
+            }
+        }
+    }
 }