Even though we have file locks for multi-process concurrency, we still need to use locking for in-process threads.

Author: ken-duck

src/main/java/net/ossindex/gradle/output/JunitXmlReportWriter.java

@@ -11,6 +11,8 @@
 import java.nio.file.attribute.PosixFilePermission;
 import java.util.ArrayList;
 import java.util.Set;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -44,6 +46,12 @@ public class JunitXmlReportWriter
 
   private Long startSeconds = null;
 
+  /**
+   * The DocResource class does a file lock preventing concurrent access from other processes, but we still need
+   * to prevent concurrent access of the document in *THIS* class.
+   */
+  private static Lock lock = new ReentrantLock();
+
   public void init(String junitReport) {
 
     if (junitReport == null) {
@@ -70,6 +78,7 @@ public void updateJunitReport(String totals,
       return;
     }
 
+    lock.lock();
     try (DocResource docResource = new DocResource(pathToReport)) {
       Document doc = docResource.getDocument();
 
@@ -94,20 +103,27 @@ public void updateJunitReport(String totals,
     catch (IOException e) {
       logger.error("Exception writing log: " + e);
     }
+    finally {
+      lock.unlock();
+    }
   }
 
   public void writeXmlReport(String pathToReport) throws Exception {
     if (skip) {
       return;
     }
 
+    lock.lock();
     try (DocResource docResource = new DocResource(pathToReport)) {
       Document doc = docResource.getDocument();
       String testCount = getTotalOfElementsByName(doc, "testcase").toString();
       modifyElementAttribute(doc, "testsuites", 0, "tests", testCount);
       String failureCount = getTotalOfElementsByName(doc, "failure").toString();
       modifyElementAttribute(doc, "testsuites", 0, "failures", failureCount);
     }
+    finally {
+      lock.unlock();
+    }
   }
 
   private Element addChildElement(Document doc, Element parent, String name, String data) {