Track condition evaluation per-context when determining delta

Closes gh-15766

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/autoconfigure/ConditionEvaluationDeltaLoggingListener.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,12 +16,16 @@
 
 package org.springframework.boot.devtools.autoconfigure;
 
+import java.util.concurrent.ConcurrentHashMap;
+
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.boot.autoconfigure.condition.ConditionEvaluationReport;
 import org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportMessage;
 import org.springframework.boot.context.event.ApplicationReadyEvent;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.ApplicationListener;
 
 /**
@@ -31,32 +35,47 @@ import org.springframework.context.ApplicationListener;
  * @author Andy Wilkinson
  */
 class ConditionEvaluationDeltaLoggingListener
-		implements ApplicationListener<ApplicationReadyEvent> {
+		implements ApplicationListener<ApplicationReadyEvent>, ApplicationContextAware {
+
+	private static final ConcurrentHashMap<String, ConditionEvaluationReport> previousReports = new ConcurrentHashMap<>();
 
-	private final Log logger = LogFactory.getLog(getClass());
+	private static final Log logger = LogFactory
+			.getLog(ConditionEvaluationDeltaLoggingListener.class);
 
-	private static ConditionEvaluationReport previousReport;
+	private volatile ApplicationContext context;
 
 	@Override
 	public void onApplicationEvent(ApplicationReadyEvent event) {
+		if (!event.getApplicationContext().equals(this.context)) {
+			return;
+		}
 		ConditionEvaluationReport report = event.getApplicationContext()
 				.getBean(ConditionEvaluationReport.class);
+		ConditionEvaluationReport previousReport = previousReports
+				.get(event.getApplicationContext().getId());
 		if (previousReport != null) {
 			ConditionEvaluationReport delta = report.getDelta(previousReport);
 			if (!delta.getConditionAndOutcomesBySource().isEmpty()
 					|| !delta.getExclusions().isEmpty()
 					|| !delta.getUnconditionalClasses().isEmpty()) {
-				if (this.logger.isInfoEnabled()) {
-					this.logger.info("Condition evaluation delta:"
-							+ new ConditionEvaluationReportMessage(delta,
-									"CONDITION EVALUATION DELTA"));
+				if (ConditionEvaluationDeltaLoggingListener.logger.isInfoEnabled()) {
+					ConditionEvaluationDeltaLoggingListener.logger
+							.info("Condition evaluation delta:"
+									+ new ConditionEvaluationReportMessage(delta,
+											"CONDITION EVALUATION DELTA"));
 				}
 			}
 			else {
-				this.logger.info("Condition evaluation unchanged");
+				ConditionEvaluationDeltaLoggingListener.logger
+						.info("Condition evaluation unchanged");
 			}
 		}
-		previousReport = report;
+		previousReports.put(event.getApplicationContext().getId(), report);
+	}
+
+	@Override
+	public void setApplicationContext(ApplicationContext applicationContext) {
+		this.context = applicationContext;
 	}
 
 }