HSEARCH-4580 "_routing" in custom Elasticsearch schema leads to "JsonIOException: JSON document was not fully consumed."

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/lowlevel/index/mapping/impl/RoutingTypeJsonAdapter.java

@@ -62,6 +62,7 @@ public RoutingType read(JsonReader in) throws IOException {
 					throw new AssertionFailure( "Unexpected property for attribute of type " + RoutingType.class + ": " + name );
 			}
 		}
+		in.endObject();
 
 		return value;
 	}

backend/elasticsearch/src/test/java/org/hibernate/search/backend/elasticsearch/gson/spi/GsonParsingTest.java

@@ -0,0 +1,55 @@
+/*
+ * Hibernate Search, full-text search for your domain model
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.search.backend.elasticsearch.gson.spi;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+
+import org.hibernate.search.backend.elasticsearch.lowlevel.index.mapping.impl.RootTypeMapping;
+import org.hibernate.search.util.impl.test.JsonHelper;
+import org.hibernate.search.util.impl.test.annotation.TestForIssue;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+
+@RunWith(Parameterized.class)
+@TestForIssue(jiraKey = "HSEARCH-4580")
+public class GsonParsingTest {
+
+	@Parameterized.Parameters
+	public static Object[][] params() {
+		return new Object[][] {
+				{ "{\"_routing\": {\"required\": true}}", RootTypeMapping.class } // HSEARCH-4580
+		};
+	}
+
+	private final Gson gson;
+
+	@Parameterized.Parameter(0)
+	public String jsonToParse;
+	@Parameterized.Parameter(1)
+	public Class<?> targetType;
+
+	public GsonParsingTest() {
+		gson = GsonProvider.create( GsonBuilder::new, true ).getGsonNoSerializeNulls();
+	}
+
+	@Test
+	public void parsingWithoutException() {
+		assertThatCode( () -> gson.fromJson( jsonToParse, targetType ) ).doesNotThrowAnyException();
+	}
+
+	@Test
+	public void noInformationLoss() {
+		Object parsed = gson.fromJson( jsonToParse, targetType );
+		String written = gson.toJson( parsed );
+		JsonHelper.assertJsonEquals( jsonToParse, written );
+	}
+}