Consistently evaluate defaultCandidate flag on constructors and methods

Closes gh-33762

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/factory/annotation/QualifierAnnotationAutowireCandidateResolver.java

@@ -154,26 +154,35 @@ public void setValueAnnotationType(Class<? extends Annotation> valueAnnotationTy
 	 */
 	@Override
 	public boolean isAutowireCandidate(BeanDefinitionHolder bdHolder, DependencyDescriptor descriptor) {
-		boolean match = super.isAutowireCandidate(bdHolder, descriptor);
-		if (match) {
-			match = checkQualifiers(bdHolder, descriptor.getAnnotations());
-			if (match) {
-				MethodParameter methodParam = descriptor.getMethodParameter();
-				if (methodParam != null) {
-					Method method = methodParam.getMethod();
-					if (method == null || void.class == method.getReturnType()) {
-						match = checkQualifiers(bdHolder, methodParam.getMethodAnnotations());
+		if (!super.isAutowireCandidate(bdHolder, descriptor)) {
+			return false;
+		}
+		Boolean checked = checkQualifiers(bdHolder, descriptor.getAnnotations());
+		if (checked != Boolean.FALSE) {
+			MethodParameter methodParam = descriptor.getMethodParameter();
+			if (methodParam != null) {
+				Method method = methodParam.getMethod();
+				if (method == null || void.class == method.getReturnType()) {
+					Boolean methodChecked = checkQualifiers(bdHolder, methodParam.getMethodAnnotations());
+					if (methodChecked != null && checked == null) {
+						checked = methodChecked;
 					}
 				}
 			}
 		}
-		return match;
+		return (checked == Boolean.TRUE ||
+				(checked == null && ((RootBeanDefinition) bdHolder.getBeanDefinition()).isDefaultCandidate()));
 	}
 
 	/**
 	 * Match the given qualifier annotations against the candidate bean definition.
+	 * @return {@code false} if a qualifier has been found but not matched,
+	 * {@code true} if a qualifier has been found and matched,
+	 * {@code null} if no qualifier has been found at all
 	 */
-	protected boolean checkQualifiers(BeanDefinitionHolder bdHolder, Annotation[] annotationsToSearch) {
+
+	@Nullable
+	protected Boolean checkQualifiers(BeanDefinitionHolder bdHolder, Annotation[] annotationsToSearch) {
 		boolean qualifierFound = false;
 		if (!ObjectUtils.isEmpty(annotationsToSearch)) {
 			SimpleTypeConverter typeConverter = new SimpleTypeConverter();
@@ -217,7 +226,7 @@ protected boolean checkQualifiers(BeanDefinitionHolder bdHolder, Annotation[] an
 				}
 			}
 		}
-		return (qualifierFound || ((RootBeanDefinition) bdHolder.getBeanDefinition()).isDefaultCandidate());
+		return (qualifierFound ? true : null);
 	}
 
 	/**

spring-context/src/test/java/org/springframework/context/annotation/configuration/BeanMethodQualificationTests.java

@@ -195,6 +195,28 @@ void customWithAttributeOverride() {
 		ctx.close();
 	}
 
+	@Test
+	void customWithConstructor() {
+		AnnotationConfigApplicationContext ctx = context(CustomConfig.class, CustomPojoWithConstructor.class);
+
+		CustomPojoWithConstructor pojo = ctx.getBean(CustomPojoWithConstructor.class);
+		assertThat(pojo.plainBean).isNull();
+		assertThat(pojo.testBean.getName()).isEqualTo("interesting");
+
+		ctx.close();
+	}
+
+	@Test
+	void customWithMethod() {
+		AnnotationConfigApplicationContext ctx = context(CustomConfig.class, CustomPojoWithMethod.class);
+
+		CustomPojoWithMethod pojo = ctx.getBean(CustomPojoWithMethod.class);
+		assertThat(pojo.plainBean).isNull();
+		assertThat(pojo.testBean.getName()).isEqualTo("interesting");
+
+		ctx.close();
+	}
+
 	@Test
 	void beanNamesForAnnotation() {
 		AnnotationConfigApplicationContext ctx = context(StandardConfig.class);
@@ -327,6 +349,7 @@ public TestBean testBean2x() {
 		}
 	}
 
+
 	@Configuration
 	static class EffectivePrimaryConfig {
 
@@ -346,6 +369,7 @@ public TestBean fallback2() {
 		}
 	}
 
+
 	@Component @Lazy
 	static class StandardPojo {
 
@@ -418,6 +442,35 @@ public CustomPojo(Optional<TestBean> plainBean) {
 	}
 
 
+	@InterestingPojo
+	static class CustomPojoWithConstructor {
+
+		TestBean plainBean;
+
+		TestBean testBean;
+
+		public CustomPojoWithConstructor(Optional<TestBean> plainBean, @InterestingNeed TestBean testBean) {
+			this.plainBean = plainBean.orElse(null);
+			this.testBean = testBean;
+		}
+	}
+
+
+	@InterestingPojo
+	static class CustomPojoWithMethod {
+
+		TestBean plainBean;
+
+		TestBean testBean;
+
+		@Autowired
+		public void applyDependencies(Optional<TestBean> plainBean, @InterestingNeed TestBean testBean) {
+			this.plainBean = plainBean.orElse(null);
+			this.testBean = testBean;
+		}
+	}
+
+
 	@Qualifier
 	@Retention(RetentionPolicy.RUNTIME)
 	@interface Boring {