Support setting log level ALL in logback

Fixes gh-8639

spring-boot/src/main/java/org/springframework/boot/logging/AbstractLoggingSystem.java

@@ -199,7 +199,9 @@ public abstract class AbstractLoggingSystem extends LoggingSystem {
 		}
 
 		public void map(LogLevel system, T nativeLevel) {
-			this.systemToNative.put(system, nativeLevel);
+			if (!this.systemToNative.containsKey(system)) {
+				this.systemToNative.put(system, nativeLevel);
+			}
 			if (!this.nativeToSystem.containsKey(nativeLevel)) {
 				this.nativeToSystem.put(nativeLevel, system);
 			}

spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackLoggingSystem.java

@@ -64,6 +64,7 @@ public class LogbackLoggingSystem extends Slf4JLoggingSystem {
 
 	static {
 		LEVELS.map(LogLevel.TRACE, Level.TRACE);
+		LEVELS.map(LogLevel.TRACE, Level.ALL);
 		LEVELS.map(LogLevel.DEBUG, Level.DEBUG);
 		LEVELS.map(LogLevel.INFO, Level.INFO);
 		LEVELS.map(LogLevel.WARN, Level.WARN);
@@ -259,7 +260,7 @@ public class LogbackLoggingSystem extends Slf4JLoggingSystem {
 		return new ShutdownHandler();
 	}
 
-	private ch.qos.logback.classic.Logger getLogger(String name) {
+	ch.qos.logback.classic.Logger getLogger(String name) {
 		LoggerContext factory = getLoggerContext();
 		if (StringUtils.isEmpty(name) || ROOT_LOGGER_NAME.equals(name)) {
 			name = Logger.ROOT_LOGGER_NAME;

spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemTests.java

@@ -23,6 +23,7 @@ import java.util.List;
 import java.util.logging.Handler;
 import java.util.logging.LogManager;
 
+import ch.qos.logback.classic.Level;
 import ch.qos.logback.classic.Logger;
 import ch.qos.logback.classic.LoggerContext;
 import ch.qos.logback.classic.spi.LoggerContextListener;
@@ -64,6 +65,7 @@ import static org.mockito.Mockito.verify;
  * @author Phillip Webb
  * @author Andy Wilkinson
  * @author Ben Hale
+ * @author Madhura Bhave
  */
 public class LogbackLoggingSystemTests extends AbstractLoggingSystemTests {
 
@@ -205,6 +207,27 @@ public class LogbackLoggingSystemTests extends AbstractLoggingSystemTests {
 				LogLevel.DEBUG, LogLevel.DEBUG));
 	}
 
+	@Test
+	public void getLoggingConfigurationForALL() throws Exception {
+		this.loggingSystem.beforeInitialize();
+		this.loggingSystem.initialize(this.initializationContext, null, null);
+		Logger logger = this.loggingSystem.getLogger(getClass().getName());
+		logger.setLevel(Level.ALL);
+		LoggerConfiguration configuration = this.loggingSystem
+				.getLoggerConfiguration(getClass().getName());
+		assertThat(configuration).isEqualTo(new LoggerConfiguration(getClass().getName(),
+				LogLevel.TRACE, LogLevel.TRACE));
+	}
+
+	@Test
+	public void systemLevelTraceShouldReturnNativeLevelTraceNotAll() throws Exception {
+		this.loggingSystem.beforeInitialize();
+		this.loggingSystem.initialize(this.initializationContext, null, null);
+		this.loggingSystem.setLogLevel(getClass().getName(), LogLevel.TRACE);
+		Logger logger = this.loggingSystem.getLogger(getClass().getName());
+		assertThat(logger.getLevel()).isEqualTo(Level.TRACE);
+	}
+
 	@Test
 	public void loggingThatUsesJulIsCaptured() {
 		this.loggingSystem.beforeInitialize();