[Bug 66184] Ensure that all root loggers have a level or parent

java/org/apache/juli/ClassLoaderLogManager.java

@@ -512,6 +512,10 @@ protected synchronized void readConfiguration(ClassLoader classLoader)
         if (is != null) {
             readConfiguration(is, classLoader);
         }
+
+        if (localRootLogger.getParent() == null && localRootLogger.getLevel() == null) {
+            localRootLogger.setLevel(Level.INFO);
+        }
         try {
             // Use a ThreadLocal to work around
             // https://bugs.openjdk.java.net/browse/JDK-8195096

test/org/apache/juli/TestClassLoaderLogManager.java

@@ -16,9 +16,17 @@
  */
 package org.apache.juli;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+import java.io.ByteArrayInputStream;
 import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
 import java.util.Collections;
 import java.util.Random;
+import java.util.logging.Level;
 import java.util.logging.LogManager;
 import java.util.logging.Logger;
 
@@ -30,6 +38,8 @@
  */
 public class TestClassLoaderLogManager {
 
+    private static final byte[] EMPTY_BYTES = {};
+
     @Test
     public void testReplace() {
         ClassLoaderLogManager logManager = new ClassLoaderLogManager();
@@ -81,6 +91,26 @@ public void testBug56082() {
         listThread.setRunning(false);
     }
 
+    /**
+     * Tests if a per-app root logger has a not {@code null} level.
+     */
+    @Test
+    public void testBug66184() throws IOException {
+        final ClassLoader cl = new TestClassLoader();
+        final ClassLoader oldCL = Thread.currentThread().getContextClassLoader();
+        try {
+            Thread.currentThread().setContextClassLoader(cl);
+            final ClassLoaderLogManager logManager = new ClassLoaderLogManager();
+            logManager.readConfiguration();
+            final Logger rootLogger = logManager.getLogger("");
+            assertNotNull("root logger is null", rootLogger);
+            assertNull("root logger has a parent", rootLogger.getParent());
+            assertEquals(Level.INFO, rootLogger.getLevel());
+        } finally {
+            Thread.currentThread().setContextClassLoader(oldCL);
+        }
+    }
+
     private static class LoggerCreateThread extends Thread {
 
         private final LogManager logManager;
@@ -133,4 +163,35 @@ public void setRunning(boolean running) {
             this.running = running;
         }
     }
+
+    private static class TestClassLoader extends ClassLoader implements WebappProperties {
+
+        @Override
+        public String getWebappName() {
+            return "webapp";
+        }
+
+        @Override
+        public String getHostName() {
+            return "localhost";
+        }
+
+        @Override
+        public String getServiceName() {
+            return "Catalina";
+        }
+
+        @Override
+        public boolean hasLoggingConfig() {
+            return true;
+        }
+
+        @Override
+        public InputStream getResourceAsStream(final String resource) {
+            if ("logging.properties".equals(resource)) {
+                return new ByteArrayInputStream(EMPTY_BYTES);
+            }
+            return null;
+        }
+    }
 }