Treat directly registered class as configuration 'lite' mode candidate

Prior to this commit, if a non-annotated [1] class was registered
directly with an ApplicationContext -- for example, via
AnnotatedBeanDefinitionReader, AnnotationConfigApplicationContext, or
@ContextConfiguration -- it was not considered a configuration class in
'lite' mode unless @Bean methods were declared locally. In other words,
if the registered class didn't declare local @Bean methods but rather
extended a class that declared @Bean methods, then the registered class
was not parsed as a @Configuration class in 'lite' mode, and the @Bean
methods were ignored.

Whereas, a non-annotated class registered via @Import is always
considered to be a configuration class candidate.

To address this discrepancy between @Import'ed classes and classes
registered directly with an ApplicationContext, this commit treats any
class registered via AnnotatedBeanDefinitionReader as a @Configuration
class candidate with @Bean 'lite' mode semantics.

[1] In this context, "non-annotated" means a class not annotated (or
meta-annotated) with @Component, @ComponentScan, @Import, or
@ImportResource.

Closes gh-30449

spring-context/src/test/java/org/springframework/context/annotation/BeanLiteModeTests.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright 2002-2023 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.context.annotation;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link Bean @Bean} 'lite' mode features that are not covered
+ * elsewhere in the test suite.
+ *
+ * @author Sam Brannen
+ * @since 6.0.10
+ * @see ConfigurationClassPostProcessorTests
+ */
+class BeanLiteModeTests {
+
+	@Test
+	void beanMethodsAreFoundWhenInheritedAsInterfaceDefaultMethods() {
+		assertBeansAreFound(InterfaceDefaultMethodsConfig.class);
+	}
+
+	@Test
+	void beanMethodsAreFoundWhenDeclaredLocally() {
+		assertBeansAreFound(BaseConfig.class);
+	}
+
+	@Test
+	void beanMethodsAreFoundWhenDeclaredLocallyAndInSuperclass() {
+		assertBeansAreFound(OverridingConfig.class, "foo", "xyz");
+	}
+
+	@Test  // gh-30449
+	void beanMethodsAreFoundWhenDeclaredOnlyInSuperclass() {
+		assertBeansAreFound(ExtendedConfig.class, "foo", "xyz");
+	}
+
+	private static void assertBeansAreFound(Class<?> configClass) {
+		assertBeansAreFound(configClass, "foo", "bar");
+	}
+
+	private static void assertBeansAreFound(Class<?> configClass, String expected1, String expected2) {
+		try (AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(configClass)) {
+			String bean1 = context.getBean("bean1", String.class);
+			String bean2 = context.getBean("bean2", String.class);
+
+			assertThat(bean1).isEqualTo(expected1);
+			assertThat(bean2).isEqualTo(expected2);
+		}
+	}
+
+
+	interface ConfigInterface {
+
+		@Bean
+		default String bean1() {
+			return "foo";
+		}
+
+		@Bean
+		default String bean2() {
+			return "bar";
+		}
+	}
+
+	static class InterfaceDefaultMethodsConfig implements ConfigInterface {
+	}
+
+	static class BaseConfig {
+
+		@Bean
+		String bean1() {
+			return "foo";
+		}
+
+		@Bean
+		String bean2() {
+			return "bar";
+		}
+	}
+
+	static class OverridingConfig extends BaseConfig {
+
+		@Bean
+		@Override
+		String bean2() {
+			return "xyz";
+		}
+	}
+
+	static class ExtendedConfig extends OverridingConfig {
+	}
+
+}