[LOG4J2-2006] RollingFile createOnDemand validation

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

@@ -0,0 +1,72 @@
+/*
+ * 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.rolling;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.File;
+import java.nio.file.Files;
+import org.apache.logging.log4j.core.config.NullConfiguration;
+import org.apache.logging.log4j.core.layout.PatternLayout;
+import org.junit.jupiter.api.Test;
+
+class RollingFileManagerCreateOnDemandTest {
+    @Test
+    void testCreateOnDemandDoesNotCreateDirectoryOrFile() throws Exception {
+        String logDir = "target/test-logs/onDemand";
+        String logFile = logDir + "/test.log";
+        File dir = new File(logDir);
+        File file = new File(logFile);
+        if (file.exists()) file.delete();
+        if (dir.exists()) dir.delete();
+        assertFalse(dir.exists(), "Directory should not exist before logging");
+        assertFalse(file.exists(), "File should not exist before logging");
+
+        RollingFileManager manager = RollingFileManager.getFileManager(
+                logFile,
+                logFile + ".%d{yyyy-MM-dd}",
+                true,
+                false,
+                NoOpTriggeringPolicy.INSTANCE,
+                DefaultRolloverStrategy.newBuilder().build(),
+                null,
+                PatternLayout.createDefaultLayout(),
+                0,
+                true,
+                true,
+                null,
+                null,
+                null,
+                new NullConfiguration());
+        assertNotNull(manager);
+        // Directory and file should still not exist
+        assertFalse(dir.exists(), "Directory should not exist after manager creation");
+        assertFalse(file.exists(), "File should not exist after manager creation");
+
+        // Log a message
+        manager.writeToDestination("Hello Log4j2".getBytes(), 0, "Hello Log4j2".length());
+        manager.close();
+
+        // Now directory and file should exist
+        assertTrue(dir.exists(), "Directory should exist after first log event");
+        assertTrue(file.exists(), "File should exist after first log event");
+        String content = new String(Files.readAllBytes(file.toPath()));
+        assertTrue(content.contains("Hello Log4j2"));
+    }
+}

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

@@ -310,14 +310,17 @@ public static RollingFileManager getFileManager(
                             if (fileName != null) {
                                 file = new File(fileName);
 
-                                try {
-                                    FileUtils.makeParentDirs(file);
-                                    final boolean created = createOnDemand ? false : file.createNewFile();
-                                    LOGGER.trace("New file '{}' created = {}", name, created);
-                                } catch (final IOException ioe) {
-                                    LOGGER.error("Unable to create file {}", name, ioe);
-                                    return null;
+                                if (!createOnDemand) {
+                                    try {
+                                        FileUtils.makeParentDirs(file);
+                                        final boolean created = file.createNewFile();
+                                        LOGGER.trace("New file '{}' created = {}", name, created);
+                                    } catch (final IOException ioe) {
+                                        LOGGER.error("Unable to create file {}", name, ioe);
+                                        return null;
+                                    }
                                 }
+
                                 size = append ? file.length() : 0;
                             }
 
@@ -391,12 +394,10 @@ public String getFileName() {
 
     @Override
     protected void createParentDir(File file) {
-        if (directWrite) {
-            final File parent = file.getParentFile();
-            // If the parent is null the file is in the current working directory.
-            if (parent != null) {
-                parent.mkdirs();
-            }
+        try {
+            FileUtils.makeParentDirs(file);
+        } catch (IOException e) {
+            LOGGER.error("Unable to create parent directories for file {}", file, e);
         }
     }