Fix t8n encoding issue

CHANGELOG.md

@@ -17,6 +17,7 @@
 ### Bug Fixes
 - do not create ignorable storage on revert storage-variables subcommand [#5830](https://github.com/hyperledger/besu/pull/5830) 
 - fix duplicate key errors in EthScheduler-Transactions [#5857](https://github.com/hyperledger/besu/pull/5857)
+- Don't put control characters, escaped or otherwise, in t8n stacktraces [#5910](https://github.com/hyperledger/besu/pull/5910)
 
 ### Download Links
 

ethereum/evmtool/build.gradle

@@ -62,6 +62,7 @@ dependencies {
   testImplementation 'org.assertj:assertj-core'
   testImplementation 'org.junit.jupiter:junit-jupiter'
   testImplementation 'org.mockito:mockito-core'
+  testImplementation 'org.mockito:mockito-junit-jupiter'
 
   testRuntimeOnly 'org.junit.vintage:junit-vintage-engine'
 

ethereum/evmtool/src/main/java/org/hyperledger/besu/evmtool/T8nServerSubCommand.java

@@ -178,7 +178,7 @@ public void disposeTracer(final OperationTracer tracer) {
       t.printStackTrace(ps);
       ObjectNode json = objectMapper.createObjectNode();
       json.put("error", t.getMessage());
-      json.put("stacktrace", baos.toString(StandardCharsets.UTF_8));
+      json.put("stacktrace", baos.toString(StandardCharsets.UTF_8).replaceAll("\\s", " "));
 
       t.printStackTrace(System.out);
 

ethereum/evmtool/src/test/java/org/hyperledger/besu/evmtool/T8nServerSubCommandTest.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright Hyperledger Besu Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.hyperledger.besu.evmtool;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.vertx.core.http.HttpServerRequest;
+import io.vertx.core.http.HttpServerResponse;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Answers;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class T8nServerSubCommandTest {
+
+  @Mock HttpServerRequest httpServerRequest;
+
+  @Mock(answer = Answers.RETURNS_SELF)
+  HttpServerResponse httpServerResponse;
+
+  @Test
+  void exceptionEncodedProperlyInJSON() {
+    T8nServerSubCommand subject = new T8nServerSubCommand();
+    ObjectMapper objectMapper = new ObjectMapper();
+
+    when(httpServerRequest.response()).thenReturn(httpServerResponse);
+
+    // Should trigger a NPE within the try block.
+    subject.handleT8nRequest(httpServerRequest, objectMapper, null, null);
+
+    ArgumentCaptor<Integer> responseCodeCaptor = ArgumentCaptor.forClass(Integer.class);
+    ArgumentCaptor<String> responseStringCaptor = ArgumentCaptor.forClass(String.class);
+
+    verify(httpServerResponse).setStatusCode(responseCodeCaptor.capture());
+    verify(httpServerResponse).end(responseStringCaptor.capture());
+
+    assertThat(responseCodeCaptor.getValue()).isEqualTo(500);
+    assertThat(responseStringCaptor.getValue()).doesNotContain("\\t");
+  }
+}