Improve diagnostics when using @ConstructorBinding on a Kotlin class

Closes gh-19312

spring-boot-project/spring-boot-autoconfigure/pom.xml

@@ -836,6 +836,16 @@
 			<optional>true</optional>
 		</dependency>
 		<!-- Test -->
+		<dependency>
+			<groupId>org.jetbrains.kotlin</groupId>
+			<artifactId>kotlin-reflect</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.jetbrains.kotlin</groupId>
+			<artifactId>kotlin-stdlib-jdk8</artifactId>
+			<scope>test</scope>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-test-support</artifactId>
@@ -993,6 +1003,29 @@
 			<scope>test</scope>
 		</dependency>
 	</dependencies>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.jetbrains.kotlin</groupId>
+				<artifactId>kotlin-maven-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>test-compile</id>
+						<phase>test-compile</phase>
+						<goals>
+							<goal>test-compile</goal>
+						</goals>
+						<configuration>
+							<sourceDirs>
+								<sourceDir>${project.basedir}/src/test/kotlin</sourceDir>
+								<sourceDir>${project.basedir}/src/test/java</sourceDir>
+							</sourceDirs>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
 	<profiles>
 		<profile>
 			<id>java9+</id>

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

@@ -46,6 +46,7 @@ import org.springframework.boot.context.properties.ConstructorBinding;
 import org.springframework.boot.diagnostics.FailureAnalysis;
 import org.springframework.boot.diagnostics.analyzer.AbstractInjectionFailureAnalyzer;
 import org.springframework.context.annotation.Bean;
+import org.springframework.core.KotlinDetector;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.MergedAnnotation;
 import org.springframework.core.annotation.MergedAnnotations;
@@ -120,10 +121,19 @@ class NoSuchBeanDefinitionFailureAnalyzer extends AbstractInjectionFailureAnalyz
 			MergedAnnotation<ConfigurationProperties> configurationProperties = MergedAnnotations.from(declaringClass)
 					.get(ConfigurationProperties.class);
 			if (configurationProperties.isPresent()) {
-				action = String.format(
-						"%s%nConsider adding @%s to %s if you intended to use constructor-based "
-								+ "configuration property binding.",
-						action, ConstructorBinding.class.getSimpleName(), constructor.getName());
+				if (KotlinDetector.isKotlinType(declaringClass) && !KotlinDetector.isKotlinReflectPresent()) {
+					action = String.format(
+							"%s%nConsider adding a dependency on kotlin-reflect so that the contructor used for @%s can be located. Also, ensure that @%s is present on '%s' if you intended to use constructor-based "
+									+ "configuration property binding.",
+							action, ConstructorBinding.class.getSimpleName(), ConstructorBinding.class.getSimpleName(),
+							constructor.getName());
+				}
+				else {
+					action = String.format(
+							"%s%nConsider adding @%s to %s if you intended to use constructor-based "
+									+ "configuration property binding.",
+							action, ConstructorBinding.class.getSimpleName(), constructor.getName());
+				}
 			}
 		}
 		return new FailureAnalysis(message.toString(), action, cause);

spring-boot-project/spring-boot-autoconfigure/src/test/kotlin/org/springframework/boot/autoconfigure/diagnostics/analyzer/KotlinNoSuchBeanFailureAnalyzerNoKotlinReflectTests.kt

@@ -0,0 +1,67 @@
+package org.springframework.boot.autoconfigure.diagnostics.analyzer
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.springframework.beans.FatalBeanException
+import org.springframework.boot.context.properties.ConfigurationProperties
+import org.springframework.boot.context.properties.ConstructorBinding
+import org.springframework.boot.context.properties.EnableConfigurationProperties
+import org.springframework.boot.diagnostics.FailureAnalysis
+import org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter
+import org.springframework.boot.test.util.TestPropertyValues
+import org.springframework.boot.testsupport.classpath.ClassPathExclusions
+import org.springframework.context.annotation.AnnotationConfigApplicationContext
+import org.springframework.context.annotation.Configuration
+
+/**
+ * Tests for {@link ConfigurationProperties @ConfigurationProperties}-annotated beans when kotlin-reflect is not present
+ * on the classpath.
+ *
+ * @author Madhura Bhave
+ */
+@ClassPathExclusions("kotlin-reflect*.jar")
+class KotlinNoSuchBeanFailureAnalyzerNoKotlinReflectTests {
+
+	private val analyzer = NoSuchBeanDefinitionFailureAnalyzer()
+
+	@Test
+	fun failureAnalysisForConfigurationPropertiesThatMaybeShouldHaveBeenConstructorBound() {
+		val analysis = analyzeFailure(
+				createFailure(ConstructorBoundConfigurationPropertiesConfiguration::class.java))
+		assertThat(analysis!!.getAction()).startsWith(
+				java.lang.String.format("Consider defining a bean of type '%s' in your configuration.", String::class.java!!.getName()))
+		assertThat(analysis!!.getAction()).contains(java.lang.String.format(
+				"Consider adding a dependency on kotlin-reflect so that the contructor used for @ConstructorBinding can be located. Also, ensure that @ConstructorBinding is present on '%s' ", ConstructorBoundProperties::class.java!!.getName()))
+	}
+
+	private fun createFailure(config: Class<*>, vararg environment: String): FatalBeanException? {
+		try {
+			AnnotationConfigApplicationContext().use { context ->
+				this.analyzer.setBeanFactory(context.beanFactory)
+				TestPropertyValues.of(*environment).applyTo(context)
+				context.register(config)
+				context.refresh()
+				return null
+			}
+		} catch (ex: FatalBeanException) {
+			return ex
+		}
+
+	}
+
+	private fun analyzeFailure(failure: Exception?): FailureAnalysis? {
+		val analysis = this.analyzer.analyze(failure)
+		if (analysis != null) {
+			LoggingFailureAnalysisReporter().report(analysis)
+		}
+		return analysis
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	@EnableConfigurationProperties(ConstructorBoundProperties::class)
+	internal class ConstructorBoundConfigurationPropertiesConfiguration
+
+	@ConfigurationProperties("test")
+	@ConstructorBinding
+	internal class ConstructorBoundProperties(val name: String)
+}