Improve diagnostics for map binding failures

Closes gh-30281

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/MapBinder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -61,6 +61,7 @@ class MapBinder extends AggregateBinder<Map<Object, Object>> {
 			if (!ConfigurationPropertyName.EMPTY.equals(name)) {
 				ConfigurationProperty property = source.getConfigurationProperty(name);
 				if (property != null && !hasDescendants) {
+					getContext().setConfigurationProperty(property);
 					return getContext().getConverter().convert(property.getValue(), target);
 				}
 				source = source.filter(name::isAncestorOf);

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/diagnostics/analyzer/BindFailureAnalyzerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -29,6 +29,7 @@ import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.diagnostics.FailureAnalysis;
+import org.springframework.boot.logging.LogLevel;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.MutablePropertySources;
@@ -89,6 +90,16 @@ class BindFailureAnalyzerTests {
 				"failed to convert java.lang.String to java.lang.Class<?> (caused by java.lang.ClassNotFoundException: com.example.Missing"));
 	}
 
+	@Test
+	void bindExceptionDueToMapConversionFailure() {
+		FailureAnalysis analysis = performAnalysis(LoggingLevelFailureConfiguration.class, "logging.level=debug");
+		assertThat(analysis.getDescription()).contains(failure("logging.level", "debug",
+				"\"logging.level\" from property source \"test\"",
+				"org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting "
+						+ "from type [java.lang.String] to type [java.util.Map<java.lang.String, "
+						+ "org.springframework.boot.logging.LogLevel>]"));
+	}
+
 	private static String failure(String property, String value, String origin, String reason) {
 		return String.format("Property: %s%n    Value: %s%n    Origin: %s%n    Reason: %s", property, value, origin,
 				reason);
@@ -151,6 +162,11 @@ class BindFailureAnalyzerTests {
 
 	}
 
+	@EnableConfigurationProperties(LoggingProperties.class)
+	static class LoggingLevelFailureConfiguration {
+
+	}
+
 	@ConfigurationProperties("test.foo")
 	@Validated
 	static class FieldValidationFailureProperties {
@@ -238,6 +254,21 @@ class BindFailureAnalyzerTests {
 
 	}
 
+	@ConfigurationProperties("logging")
+	static class LoggingProperties {
+
+		private Map<String, LogLevel> level = new HashMap<>();
+
+		Map<String, LogLevel> getLevel() {
+			return this.level;
+		}
+
+		void setLevel(Map<String, LogLevel> level) {
+			this.level = level;
+		}
+
+	}
+
 	enum Fruit {
 
 		APPLE, BANANA, ORANGE