Remove unnecessary code

Remove code from `LogbackLoggingSystem.loadDefaults` that sets Logback
context properties from the Spring Environment. The code should not be
required since `LoggingSystemVariables` will have already set system
variables for the logging config to use.

Closes gh-23767

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

@@ -48,12 +48,10 @@ import org.springframework.boot.logging.LoggerConfiguration;
 import org.springframework.boot.logging.LoggingInitializationContext;
 import org.springframework.boot.logging.LoggingSystem;
 import org.springframework.boot.logging.LoggingSystemFactory;
-import org.springframework.boot.logging.LoggingSystemProperties;
 import org.springframework.boot.logging.Slf4JLoggingSystem;
 import org.springframework.core.Ordered;
 import org.springframework.core.SpringProperties;
 import org.springframework.core.annotation.Order;
-import org.springframework.core.env.Environment;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ResourceUtils;
@@ -142,13 +140,6 @@ public class LogbackLoggingSystem extends Slf4JLoggingSystem {
 		}
 		LogbackConfigurator configurator = debug ? new DebugLogbackConfigurator(context)
 				: new LogbackConfigurator(context);
-		Environment environment = initializationContext.getEnvironment();
-		context.putProperty(LoggingSystemProperties.LOG_LEVEL_PATTERN,
-				environment.resolvePlaceholders("${logging.pattern.level:${LOG_LEVEL_PATTERN:%5p}}"));
-		context.putProperty(LoggingSystemProperties.LOG_DATEFORMAT_PATTERN, environment.resolvePlaceholders(
-				"${logging.pattern.dateformat:${LOG_DATEFORMAT_PATTERN:yyyy-MM-dd HH:mm:ss.SSS}}"));
-		context.putProperty(LoggingSystemProperties.ROLLING_FILE_NAME_PATTERN, environment
-				.resolvePlaceholders("${logging.pattern.rolling-file-name:${LOG_FILE}.%d{yyyy-MM-dd}.%i.gz}"));
 		new DefaultLogbackConfiguration(initializationContext, logFile).apply(configurator);
 		context.setPackagingDataEnabled(true);
 	}

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

@@ -19,7 +19,9 @@ package org.springframework.boot.logging.logback;
 import java.io.File;
 import java.util.Arrays;
 import java.util.EnumSet;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.logging.Handler;
 import java.util.logging.LogManager;
 
@@ -79,8 +81,11 @@ class LogbackLoggingSystemTests extends AbstractLoggingSystemTests {
 
 	private LoggingInitializationContext initializationContext;
 
+	private Set<Object> systemPropertyNames;
+
 	@BeforeEach
 	void setup() {
+		this.systemPropertyNames = new HashSet<>(System.getProperties().keySet());
 		this.loggingSystem.cleanUp();
 		this.logger = ((LoggerContext) StaticLoggerBinder.getSingleton().getLoggerFactory()).getLogger(getClass());
 		MockEnvironment environment = new MockEnvironment();
@@ -89,6 +94,7 @@ class LogbackLoggingSystemTests extends AbstractLoggingSystemTests {
 
 	@AfterEach
 	void cleanUp() {
+		System.getProperties().keySet().retainAll(this.systemPropertyNames);
 		this.loggingSystem.cleanUp();
 		((LoggerContext) StaticLoggerBinder.getSingleton().getLoggerFactory()).stop();
 	}
@@ -302,6 +308,7 @@ class LogbackLoggingSystemTests extends AbstractLoggingSystemTests {
 	void testLevelPatternProperty(CapturedOutput output) {
 		MockEnvironment environment = new MockEnvironment();
 		environment.setProperty("logging.pattern.level", "X%clr(%p)X");
+		new LoggingSystemProperties(environment).apply();
 		LoggingInitializationContext loggingInitializationContext = new LoggingInitializationContext(environment);
 		this.loggingSystem.initialize(loggingInitializationContext, null, null);
 		this.logger.info("Hello world");
@@ -514,6 +521,7 @@ class LogbackLoggingSystemTests extends AbstractLoggingSystemTests {
 	void testDateformatPatternProperty(CapturedOutput output) {
 		MockEnvironment environment = new MockEnvironment();
 		environment.setProperty("logging.pattern.dateformat", "yyyy-MM-dd'T'hh:mm:ss.SSSZ");
+		new LoggingSystemProperties(environment).apply();
 		LoggingInitializationContext loggingInitializationContext = new LoggingInitializationContext(environment);
 		this.loggingSystem.initialize(loggingInitializationContext, null, null);
 		this.logger.info("Hello world");