Perform analysis even when property is not in the environment

Closes gh-33261

Author: wilkinsona

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/diagnostics/analyzer/InvalidConfigurationPropertyValueFailureAnalyzer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -51,7 +51,7 @@ class InvalidConfigurationPropertyValueFailureAnalyzer
 	protected FailureAnalysis analyze(Throwable rootFailure, InvalidConfigurationPropertyValueException cause) {
 		List<Descriptor> descriptors = getDescriptors(cause.getName());
 		if (descriptors.isEmpty()) {
-			return null;
+			descriptors = List.of(new Descriptor(null, cause.getValue(), null));
 		}
 		StringBuilder description = new StringBuilder();
 		appendDetails(description, cause, descriptors);

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -45,7 +45,8 @@ void analysisWithNullEnvironment() {
 		InvalidConfigurationPropertyValueException failure = new InvalidConfigurationPropertyValueException(
 				"test.property", "invalid", "This is not valid.");
 		FailureAnalysis analysis = new InvalidConfigurationPropertyValueFailureAnalyzer(null).analyze(failure);
-		assertThat(analysis).isNull();
+		assertThat(analysis.getDescription())
+			.contains("Invalid value 'invalid' for configuration property 'test.property'.");
 	}
 
 	@Test
@@ -98,7 +99,9 @@ void analysisWithKnownPropertyAndOtherCandidates() {
 	void analysisWithUnknownKey() {
 		InvalidConfigurationPropertyValueException failure = new InvalidConfigurationPropertyValueException(
 				"test.key.not.defined", "invalid", "This is not valid.");
-		assertThat(performAnalysis(failure)).isNull();
+		FailureAnalysis analysis = performAnalysis(failure);
+		assertThat(analysis.getDescription())
+			.contains("Invalid value 'invalid' for configuration property 'test.key.not.defined'.");
 	}
 
 	private void assertCommonParts(InvalidConfigurationPropertyValueException failure, FailureAnalysis analysis) {