Always accept existing explicit definition for same class name

See gh-25952

spring-context/src/main/java/org/springframework/context/annotation/ClassPathBeanDefinitionScanner.java

@@ -33,6 +33,7 @@ import org.springframework.core.env.StandardEnvironment;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
 import org.springframework.util.PatternMatchUtils;
 
 /**
@@ -345,7 +346,8 @@ public class ClassPathBeanDefinitionScanner extends ClassPathScanningCandidateCo
 
 		// Explicitly registered overriding bean?
 		if (!(existingDef instanceof ScannedGenericBeanDefinition) &&
-				this.registry.isBeanDefinitionOverridable(beanName)) {
+				(this.registry.isBeanDefinitionOverridable(beanName) || ObjectUtils.nullSafeEquals(
+						beanDefinition.getBeanClassName(), existingDef.getBeanClassName()))) {
 			return false;
 		}
 

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

@@ -215,6 +215,18 @@ public class ClassPathBeanDefinitionScannerTests {
 				.withMessageContaining(StubFooDao.class.getName());
 	}
 
+	@Test
+	public void testSimpleScanWithDefaultFiltersAndOverridingBeanAcceptedForSameBeanClass() {
+		GenericApplicationContext context = new GenericApplicationContext();
+		context.getDefaultListableBeanFactory().setAllowBeanDefinitionOverriding(false);
+		context.registerBeanDefinition("stubFooDao", new RootBeanDefinition(StubFooDao.class));
+		ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(context);
+		scanner.setIncludeAnnotationConfig(false);
+
+		// should not fail!
+		scanner.scan(BASE_PACKAGE);
+	}
+
 	@Test
 	public void testSimpleScanWithDefaultFiltersAndDefaultBeanNameClash() {
 		GenericApplicationContext context = new GenericApplicationContext();