[LOG4J2-3404] Creates default layouts using the available Configuration

log4j-core/src/main/java/org/apache/logging/log4j/core/appender/AbstractAppender.java

@@ -76,14 +76,14 @@ public String getName() {
 
         public Layout<? extends Serializable> getOrCreateLayout() {
             if (layout == null) {
-                return PatternLayout.createDefaultLayout();
+                return PatternLayout.createDefaultLayout(configuration);
             }
             return layout;
         }
 
         public Layout<? extends Serializable> getOrCreateLayout(final Charset charset) {
             if (layout == null) {
-                return PatternLayout.newBuilder().withCharset(charset).build();
+                return PatternLayout.newBuilder().withCharset(charset).withConfiguration(configuration).build();
             }
             return layout;
         }

log4j-core/src/main/java/org/apache/logging/log4j/core/appender/AbstractManager.java

@@ -204,6 +204,13 @@ protected static StatusLogger logger() {
         return StatusLogger.getLogger();
     }
 
+    /**
+     * For testing purposes.
+     */
+    static int getManagerCount() {
+        return MAP.size();
+    }
+
     /**
      * May be overridden by managers to perform processing while the manager is being released and the
      * lock is held. A timeout is passed for implementors to use as they see fit.

log4j-core/src/main/java/org/apache/logging/log4j/core/appender/OutputStreamAppender.java

@@ -57,10 +57,8 @@ public static class Builder<B extends Builder<B>> extends AbstractOutputStreamAp
 
         @Override
         public OutputStreamAppender build() {
-            final Layout<? extends Serializable> layout = getLayout();
-            final Layout<? extends Serializable> actualLayout = layout == null ? PatternLayout.createDefaultLayout()
-                    : layout;
-            return new OutputStreamAppender(getName(), actualLayout, getFilter(), getManager(target, follow, actualLayout),
+            final Layout<? extends Serializable> layout = getOrCreateLayout();
+            return new OutputStreamAppender(getName(), layout, getFilter(), getManager(target, follow, layout),
                     ignoreExceptions, getPropertyArray());
         }
 

log4j-core/src/main/java/org/apache/logging/log4j/core/appender/WriterAppender.java

@@ -16,11 +16,13 @@
  */
 package org.apache.logging.log4j.core.appender;
 
+import java.io.Serializable;
 import java.io.Writer;
 
 import org.apache.logging.log4j.core.Appender;
 import org.apache.logging.log4j.core.Core;
 import org.apache.logging.log4j.core.Filter;
+import org.apache.logging.log4j.core.Layout;
 import org.apache.logging.log4j.core.StringLayout;
 import org.apache.logging.log4j.core.config.Property;
 import org.apache.logging.log4j.core.config.plugins.Plugin;
@@ -47,9 +49,13 @@ public static class Builder<B extends Builder<B>> extends AbstractAppender.Build
 
         @Override
         public WriterAppender build() {
-            final StringLayout layout = (StringLayout) getLayout();
-            final StringLayout actualLayout = layout != null ? layout : PatternLayout.createDefaultLayout();
-            return new WriterAppender(getName(), actualLayout, getFilter(), getManager(target, follow, actualLayout),
+            final Layout<? extends Serializable> layout = getOrCreateLayout();
+            if (!(layout instanceof StringLayout)) {
+                LOGGER.error("Layout must be a StringLayout to log to ServletContext");
+                return null;
+            }
+            final StringLayout stringLayout = (StringLayout) layout;
+            return new WriterAppender(getName(), stringLayout, getFilter(), getManager(target, follow, stringLayout),
                     isIgnoreExceptions(), getPropertyArray());
         }
 

log4j-core/src/main/java/org/apache/logging/log4j/core/config/AbstractConfiguration.java

@@ -714,6 +714,12 @@ protected void doConfigure() {
         setParents();
     }
 
+    public static Level getDefaultLevel() {
+        final String levelName = PropertiesUtil.getProperties().getStringProperty(DefaultConfiguration.DEFAULT_LEVEL,
+                Level.ERROR.name());
+        return Level.valueOf(levelName);
+    }
+
     protected void setToDefault() {
         // LOG4J2-1176 facilitate memory leak investigation
         setName(DefaultConfiguration.DEFAULT_NAME + "@" + Integer.toHexString(hashCode()));
@@ -727,11 +733,7 @@ protected void setToDefault() {
         final LoggerConfig rootLoggerConfig = getRootLogger();
         rootLoggerConfig.addAppender(appender, null, null);
 
-        final Level defaultLevel = Level.ERROR;
-        final String levelName = PropertiesUtil.getProperties().getStringProperty(DefaultConfiguration.DEFAULT_LEVEL,
-                defaultLevel.name());
-        final Level level = Level.valueOf(levelName);
-        rootLoggerConfig.setLevel(level != null ? level : defaultLevel);
+        rootLoggerConfig.setLevel(getDefaultLevel());
     }
 
     /**

log4j-core/src/main/java/org/apache/logging/log4j/core/layout/AbstractLayout.java

@@ -129,7 +129,7 @@ public AbstractLayout(final byte[] header, final byte[] footer) {
      * Constructs a layout with an optional header and footer.
      *
      * @param configuration
-     *            The configuration
+     *            The configuration. May be null.
      * @param header
      *            The header to include when the stream is opened. May be null.
      * @param footer

log4j-core/src/main/java/org/apache/logging/log4j/core/layout/AbstractStringLayout.java

@@ -19,8 +19,11 @@
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.core.LogEvent;
 import org.apache.logging.log4j.core.StringLayout;
+import org.apache.logging.log4j.core.config.AbstractConfiguration;
 import org.apache.logging.log4j.core.config.Configuration;
 import org.apache.logging.log4j.core.config.LoggerConfig;
 import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
@@ -176,7 +179,7 @@ protected AbstractStringLayout(final Charset aCharset, final byte[] header, fina
 
     /**
      * Builds a new layout.
-     * @param config the configuration
+     * @param config the configuration. May be null.
      * @param aCharset the charset used to encode the header bytes, footer bytes and anything else that needs to be
      *      converted from strings to bytes.
      * @param headerSerializer the header bytes serializer
@@ -264,10 +267,19 @@ protected String serializeToString(final Serializer serializer) {
         if (serializer == null) {
             return null;
         }
-        final LoggerConfig rootLogger = getConfiguration().getRootLogger();
+        final String loggerName;
+        final Level level;
+        if (configuration != null) {
+            final LoggerConfig rootLogger = configuration.getRootLogger();
+            loggerName = rootLogger.getName();
+            level = rootLogger.getLevel();
+        } else {
+            loggerName = LogManager.ROOT_LOGGER_NAME;
+            level = AbstractConfiguration.getDefaultLevel();
+        }
         // Using "" for the FQCN, does it matter?
-        final LogEvent logEvent = getLogEventFactory().createEvent(rootLogger.getName(), null, Strings.EMPTY,
-                rootLogger.getLevel(), null, null, null);
+        final LogEvent logEvent = getLogEventFactory().createEvent(loggerName, null, Strings.EMPTY,
+                level, null, null, null);
         return serializer.toSerializable(logEvent);
     }
 

log4j-core/src/main/java/org/apache/logging/log4j/core/layout/PatternLayout.java

@@ -25,7 +25,6 @@
 import org.apache.logging.log4j.core.Layout;
 import org.apache.logging.log4j.core.LogEvent;
 import org.apache.logging.log4j.core.config.Configuration;
-import org.apache.logging.log4j.core.config.DefaultConfiguration;
 import org.apache.logging.log4j.core.config.Node;
 import org.apache.logging.log4j.core.config.plugins.Plugin;
 import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
@@ -243,7 +242,7 @@ private StringBuilder toText(final Serializer2 serializer, final LogEvent event,
 
     /**
      * Creates a PatternParser.
-     * @param config The Configuration.
+     * @param config The Configuration or {@code null}.
      * @return The PatternParser.
      */
     public static PatternParser createPatternParser(final Configuration config) {
@@ -763,10 +762,7 @@ public Builder withFooter(final String footer) {
 
         @Override
         public PatternLayout build() {
-            // fall back to DefaultConfiguration
-            if (configuration == null) {
-                configuration = new DefaultConfiguration();
-            }
+            // should work with a null configuration
             return new PatternLayout(configuration, regexReplacement, pattern, patternSelector, charset,
                 alwaysWriteExceptions, disableAnsi, noConsoleNoAnsi, header, footer);
         }

log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/PatternParser.java

@@ -103,11 +103,11 @@ public PatternParser(final String converterKey) {
      * Constructor.
      *
      * @param config
-     *            The current Configuration.
+     *            The current Configuration or {@code null}.
      * @param converterKey
      *            The key to lookup the converters.
      * @param expected
-     *            The expected base Class of each Converter.
+     *            The expected base Class of each Converter or {@code null}.
      */
     public PatternParser(final Configuration config, final String converterKey, final Class<?> expected) {
         this(config, converterKey, expected, null);
@@ -117,13 +117,13 @@ public PatternParser(final Configuration config, final String converterKey, fina
      * Constructor.
      *
      * @param config
-     *            The current Configuration.
+     *            The current Configuration or {@code null}.
      * @param converterKey
      *            The key to lookup the converters.
      * @param expectedClass
-     *            The expected base Class of each Converter.
+     *            The expected base Class of each Converter or {@code null}.
      * @param filterClass
-     *            Filter the returned plugins after calling the plugin manager.
+     *            Filter the returned plugins after calling the plugin manager, can be {@code null}.
      */
     public PatternParser(final Configuration config, final String converterKey, final Class<?> expectedClass,
             final Class<?> filterClass) {

log4j-core/src/test/java/org/apache/logging/log4j/core/appender/AbstractAppenderBuilderTest.java

@@ -0,0 +1,37 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+package org.apache.logging.log4j.core.appender;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.apache.logging.log4j.core.config.Configuration;
+import org.apache.logging.log4j.core.config.DefaultConfiguration;
+import org.junit.jupiter.api.Test;
+
+public class AbstractAppenderBuilderTest {
+
+    @Test
+    public void testDefaultLayoutLeak() {
+        int expected = AbstractManager.getManagerCount();
+        final Configuration configuration = new DefaultConfiguration();
+        ConsoleAppender appender = ConsoleAppender.newBuilder().setConfiguration(configuration).setName("test").build();
+        configuration.addAppender(appender);
+        configuration.start();
+        configuration.stop();
+        assertEquals(expected, AbstractManager.getManagerCount(), "No managers should be left after shutdown.");
+    }
+}

log4j-core/src/test/java/org/apache/logging/log4j/core/layout/AbstractStringLayoutTest.java

@@ -15,23 +15,33 @@
  * limitations under the license.
  */
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+
 import java.nio.charset.Charset;
 
 import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.config.DefaultConfiguration;
+import org.apache.logging.log4j.core.layout.AbstractStringLayout.Serializer;
+import org.apache.logging.log4j.core.layout.PatternLayout.SerializerBuilder;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.*;
-
 /**
  * Tests AbstractStringLayout.
  */
 public class AbstractStringLayoutTest {
+
+    // Configuration explicitly null
+    private static final Serializer serializer = new SerializerBuilder().setPattern(DefaultConfiguration.DEFAULT_PATTERN).build();
+
     static class ConcreteStringLayout extends AbstractStringLayout {
         public static int DEFAULT_STRING_BUILDER_SIZE = AbstractStringLayout.DEFAULT_STRING_BUILDER_SIZE;
         public static int MAX_STRING_BUILDER_SIZE = AbstractStringLayout.MAX_STRING_BUILDER_SIZE;
 
         public ConcreteStringLayout() {
-            super(Charset.defaultCharset());
+            // Configuration explicitly null
+            super(null, Charset.defaultCharset(), serializer, serializer);
         }
 
         public static StringBuilder getStringBuilder() {
@@ -76,4 +86,14 @@ public void testGetStringBuilderCapacityRestrictedToMax() throws Exception {
                 "capacity, trimmed to MAX_STRING_BUILDER_SIZE");
         assertEquals(0, sb3.length(), "empty, ready for use");
     }
+
+    @Test
+    public void testNullConfigurationIsAllowed() {
+        try {
+            final ConcreteStringLayout layout = new ConcreteStringLayout();
+            layout.serializeToString(serializer);
+        } catch (NullPointerException e) {
+            fail(e);
+        }
+    }
 }

log4j-jakarta-web/src/main/java/org/apache/logging/log4j/web/appender/ServletAppender.java

@@ -23,13 +23,13 @@
 import org.apache.logging.log4j.core.Filter;
 import org.apache.logging.log4j.core.Layout;
 import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.StringLayout;
 import org.apache.logging.log4j.core.appender.AbstractAppender;
 import org.apache.logging.log4j.core.config.Property;
 import org.apache.logging.log4j.core.config.plugins.Plugin;
 import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
 import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
 import org.apache.logging.log4j.core.layout.AbstractStringLayout;
-import org.apache.logging.log4j.core.layout.PatternLayout;
 import org.apache.logging.log4j.web.WebLoggerContextUtils;
 
 /**
@@ -55,10 +55,8 @@ public ServletAppender build() {
 				LOGGER.error("No servlet context is available");
 				return null;
 			}
-			Layout<? extends Serializable> layout = getLayout();
-			if (layout == null) {
-				layout = PatternLayout.createDefaultLayout();
-			} else if (!(layout instanceof AbstractStringLayout)) {
+			Layout<? extends Serializable> layout = getOrCreateLayout();
+			if (!(layout instanceof StringLayout)) {
 				LOGGER.error("Layout must be a StringLayout to log to ServletContext");
 				return null;
 			}

log4j-web/src/main/java/org/apache/logging/log4j/web/appender/ServletAppender.java

@@ -23,13 +23,13 @@
 import org.apache.logging.log4j.core.Filter;
 import org.apache.logging.log4j.core.Layout;
 import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.StringLayout;
 import org.apache.logging.log4j.core.appender.AbstractAppender;
 import org.apache.logging.log4j.core.config.Property;
 import org.apache.logging.log4j.core.config.plugins.Plugin;
 import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
 import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
 import org.apache.logging.log4j.core.layout.AbstractStringLayout;
-import org.apache.logging.log4j.core.layout.PatternLayout;
 import org.apache.logging.log4j.web.WebLoggerContextUtils;
 
 /**
@@ -55,10 +55,8 @@ public ServletAppender build() {
 				LOGGER.error("No servlet context is available");
 				return null;
 			}
-			Layout<? extends Serializable> layout = getLayout();
-			if (layout == null) {
-				layout = PatternLayout.createDefaultLayout();
-			} else if (!(layout instanceof AbstractStringLayout)) {
+			final Layout<? extends Serializable> layout = getOrCreateLayout();
+			if (!(layout instanceof StringLayout)) {
 				LOGGER.error("Layout must be a StringLayout to log to ServletContext");
 				return null;
 			}