Keep fallback flag in AOT-generated code

Closes gh-33261

Author: snicoll

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

@@ -115,6 +115,8 @@ CodeBlock generateCode(RootBeanDefinition beanDefinition) {
 		CodeBlock.Builder code = CodeBlock.builder();
 		addStatementForValue(code, beanDefinition, BeanDefinition::isPrimary,
 				"$L.setPrimary($L)");
+		addStatementForValue(code, beanDefinition, BeanDefinition::isFallback,
+				"$L.setFallback($L)");
 		addStatementForValue(code, beanDefinition, BeanDefinition::getScope,
 				this::hasScope, "$L.setScope($S)");
 		addStatementForValue(code, beanDefinition, BeanDefinition::getDependsOn,

Diff for: spring-beans/src/test/java/org/springframework/beans/factory/aot/BeanDefinitionPropertiesCodeGeneratorTests.java

@@ -92,6 +92,21 @@ void setPrimaryWhenTrue() {
 		compile((actual, compiled) -> assertThat(actual.isPrimary()).isTrue());
 	}
 
+	@Test
+	void setFallbackWhenFalse() {
+		this.beanDefinition.setFallback(false);
+		compile((actual, compiled) -> {
+			assertThat(compiled.getSourceFile()).doesNotContain("setFallback");
+			assertThat(actual.isFallback()).isFalse();
+		});
+	}
+
+	@Test
+	void setFallbackWhenTrue() {
+		this.beanDefinition.setFallback(true);
+		compile((actual, compiled) -> assertThat(actual.isFallback()).isTrue());
+	}
+
 	@Test
 	void setScopeWhenEmptyString() {
 		this.beanDefinition.setScope("");