Allow registering aliases with BeanRegistry

Closes gh-34599

Author: sdeleuze

Diff for: spring-beans/src/main/java/org/springframework/beans/factory/BeanRegistry.java

@@ -38,6 +38,15 @@
  */
 public interface BeanRegistry {
 
+	/**
+	 * Given a name, register an alias for it.
+	 * @param name the canonical name
+	 * @param alias the alias to be registered
+	 * @throws IllegalStateException if the alias is already in use
+	 * and may not be overridden
+	 */
+	void registerAlias(String name, String alias);
+
 	/**
 	 * Register a bean from the given bean class, which will be instantiated
 	 * using the related {@link BeanUtils#getResolvableConstructor resolvable constructor}

Diff for: spring-beans/src/main/java/org/springframework/beans/factory/support/BeanRegistryAdapter.java

@@ -80,6 +80,11 @@ public BeanRegistryAdapter(BeanDefinitionRegistry beanRegistry, ListableBeanFact
 	}
 
 
+	@Override
+	public void registerAlias(String name, String alias) {
+		this.beanRegistry.registerAlias(name, alias);
+	}
+
 	@Override
 	public <T> String registerBean(Class<T> beanClass) {
 		String beanName = BeanDefinitionReaderUtils.uniqueBeanName(beanClass.getName(), this.beanRegistry);

Diff for: spring-beans/src/main/kotlin/org/springframework/beans/factory/BeanRegistrarDsl.kt

@@ -64,6 +64,17 @@ open class BeanRegistrarDsl(private val init: BeanRegistrarDsl.() -> Unit): Bean
 	 */
 	lateinit var env: Environment
 
+	/**
+	 * Given a name, register an alias for it.
+	 * @param name the canonical name
+	 * @param alias the alias to be registered
+	 * @throws IllegalStateException if the alias is already in use
+	 * and may not be overridden
+	 */
+	fun registerAlias(name: String, alias: String) {
+		registry.registerAlias(name, alias);
+	}
+
 	/**
 	 * Register a bean from the given bean class, which will be instantiated
 	 * using the related [resolvable constructor]

Diff for: spring-context/src/test/java/org/springframework/context/annotation/beanregistrar/BeanRegistrarConfigurationTests.java

@@ -45,6 +45,7 @@ public class BeanRegistrarConfigurationTests {
 	void beanRegistrar() {
 		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(BeanRegistrarConfiguration.class);
 		assertThat(context.getBean(Bar.class).foo()).isEqualTo(context.getBean(Foo.class));
+		assertThat(context.getBean("foo", Foo.class)).isEqualTo(context.getBean("fooAlias", Foo.class));
 		assertThatThrownBy(() -> context.getBean(Baz.class)).isInstanceOf(NoSuchBeanDefinitionException.class);
 		assertThat(context.getBean(Init.class).initialized).isTrue();
 		BeanDefinition beanDefinition = context.getBeanDefinition("bar");

Diff for: spring-context/src/test/kotlin/org/springframework/context/annotation/BeanRegistrarDslConfigurationTests.kt

@@ -39,6 +39,7 @@ class BeanRegistrarDslConfigurationTests {
 	fun beanRegistrar() {
 		val context = AnnotationConfigApplicationContext(BeanRegistrarKotlinConfiguration::class.java)
 		assertThat(context.getBean<Bar>().foo).isEqualTo(context.getBean<Foo>())
+		assertThat(context.getBean<Foo>("foo")).isEqualTo(context.getBean<Foo>("fooAlias"))
 		assertThatThrownBy(ThrowableAssert.ThrowingCallable { context.getBean<Baz>() }).isInstanceOf(NoSuchBeanDefinitionException::class.java)
 		assertThat(context.getBean<Init>().initialized).isTrue()
 		val beanDefinition = context.getBeanDefinition("bar")
@@ -88,7 +89,8 @@ class BeanRegistrarDslConfigurationTests {
 	internal class BeanRegistrarKotlinConfiguration
 
 	private class SampleBeanRegistrar : BeanRegistrarDsl({
-		registerBean<Foo>()
+		registerBean<Foo>("foo")
+		registerAlias("foo", "fooAlias")
 		registerBean(
 			name = "bar",
 			prototype = true,

Diff for: spring-context/src/testFixtures/java/org/springframework/context/testfixture/beans/factory/SampleBeanRegistrar.java

@@ -27,6 +27,7 @@ public class SampleBeanRegistrar implements BeanRegistrar {
 	@Override
 	public void register(BeanRegistry registry, Environment env) {
 		registry.registerBean("foo", Foo.class);
+		registry.registerAlias("foo", "fooAlias");
 		registry.registerBean("bar", Bar.class, spec -> spec
 				.prototype()
 				.lazyInit()