Fix XML parser default value handling

The xml parser does not fill in defaults provided in the XSD when
validation is disabled. As a result, attributes like default-lazy-init
will not receive the value "default" but an empty string.

With this commit, BeanDefinitionParserDelegate now takes this into
account, checking default values against empty string as well as
"default".

As a consequence, default-lazy-init attribute should now work correctly
even when the XSD validation is disabled.

Issue: SPR-8335

spring-beans/src/main/java/org/springframework/beans/factory/xml/BeanDefinitionParserDelegate.java

 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -340,21 +340,21 @@ public class BeanDefinitionParserDelegate {
 	 */
 	protected void populateDefaults(DocumentDefaultsDefinition defaults, DocumentDefaultsDefinition parentDefaults, Element root) {
 		String lazyInit = root.getAttribute(DEFAULT_LAZY_INIT_ATTRIBUTE);
-		if (DEFAULT_VALUE.equals(lazyInit)) {
+		if (isDefaultValue(lazyInit)) {
 			// Potentially inherited from outer <beans> sections, otherwise falling back to false.
 			lazyInit = (parentDefaults != null ? parentDefaults.getLazyInit() : FALSE_VALUE);
 		}
 		defaults.setLazyInit(lazyInit);
 
 		String merge = root.getAttribute(DEFAULT_MERGE_ATTRIBUTE);
-		if (DEFAULT_VALUE.equals(merge)) {
+		if (isDefaultValue(merge)) {
 			// Potentially inherited from outer <beans> sections, otherwise falling back to false.
 			merge = (parentDefaults != null ? parentDefaults.getMerge() : FALSE_VALUE);
 		}
 		defaults.setMerge(merge);
 
 		String autowire = root.getAttribute(DEFAULT_AUTOWIRE_ATTRIBUTE);
-		if (DEFAULT_VALUE.equals(autowire)) {
+		if (isDefaultValue(autowire)) {
 			// Potentially inherited from outer <beans> sections, otherwise falling back to 'no'.
 			autowire = (parentDefaults != null ? parentDefaults.getAutowire() : AUTOWIRE_NO_VALUE);
 		}
@@ -593,7 +593,7 @@ public class BeanDefinitionParserDelegate {
 		}
 
 		String lazyInit = ele.getAttribute(LAZY_INIT_ATTRIBUTE);
-		if (DEFAULT_VALUE.equals(lazyInit)) {
+		if (isDefaultValue(lazyInit)) {
 			lazyInit = this.defaults.getLazyInit();
 		}
 		bd.setLazyInit(TRUE_VALUE.equals(lazyInit));
@@ -610,7 +610,7 @@ public class BeanDefinitionParserDelegate {
 		}
 
 		String autowireCandidate = ele.getAttribute(AUTOWIRE_CANDIDATE_ATTRIBUTE);
-		if ("".equals(autowireCandidate) || DEFAULT_VALUE.equals(autowireCandidate)) {
+		if (isDefaultValue(autowireCandidate)) {
 			String candidatePattern = this.defaults.getAutowireCandidates();
 			if (candidatePattern != null) {
 				String[] patterns = StringUtils.commaDelimitedListToStringArray(candidatePattern);
@@ -691,7 +691,7 @@ public class BeanDefinitionParserDelegate {
 	@SuppressWarnings("deprecation")
 	public int getAutowireMode(String attValue) {
 		String att = attValue;
-		if (DEFAULT_VALUE.equals(att)) {
+		if (isDefaultValue(att)) {
 			att = this.defaults.getAutowire();
 		}
 		int autowire = AbstractBeanDefinition.AUTOWIRE_NO;
@@ -1390,7 +1390,7 @@ public class BeanDefinitionParserDelegate {
 	 */
 	public boolean parseMergeAttribute(Element collectionElement) {
 		String value = collectionElement.getAttribute(MERGE_ATTRIBUTE);
-		if (DEFAULT_VALUE.equals(value)) {
+		if (isDefaultValue(value)) {
 			value = this.defaults.getMerge();
 		}
 		return TRUE_VALUE.equals(value);
@@ -1519,6 +1519,10 @@ public class BeanDefinitionParserDelegate {
 		return isDefaultNamespace(getNamespaceURI(node));
 	}
 
+	private boolean isDefaultValue(String value) {
+		return (DEFAULT_VALUE.equals(value) || "".equals(value));
+	}
+
 	private boolean isCandidateElement(Node node) {
 		return (node instanceof Element && (isDefaultNamespace(node) || !isDefaultNamespace(node.getParentNode())));
 	}

spring-beans/src/test/java/org/springframework/beans/factory/xml/NestedBeansElementAttributeRecursionTests.java

 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -41,6 +41,21 @@ public class NestedBeansElementAttributeRecursionTests {
 		new XmlBeanDefinitionReader(bf).loadBeanDefinitions(
 				new ClassPathResource("NestedBeansElementAttributeRecursionTests-lazy-context.xml", this.getClass()));
 
+		assertLazyInits(bf);
+	}
+
+	@Test
+	public void defaultLazyInitWithNonValidatingParser() {
+		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
+		XmlBeanDefinitionReader xmlBeanDefinitionReader = new XmlBeanDefinitionReader(bf);
+		xmlBeanDefinitionReader.setValidating(false);
+		xmlBeanDefinitionReader.loadBeanDefinitions(
+				new ClassPathResource("NestedBeansElementAttributeRecursionTests-lazy-context.xml", this.getClass()));
+
+		assertLazyInits(bf);
+	}
+
+	private void assertLazyInits(DefaultListableBeanFactory bf) {
 		BeanDefinition foo = bf.getBeanDefinition("foo");
 		BeanDefinition bar = bf.getBeanDefinition("bar");
 		BeanDefinition baz = bf.getBeanDefinition("baz");
@@ -61,6 +76,22 @@ public class NestedBeansElementAttributeRecursionTests {
 		new XmlBeanDefinitionReader(bf).loadBeanDefinitions(
 				new ClassPathResource("NestedBeansElementAttributeRecursionTests-merge-context.xml", this.getClass()));
 
+		assertMerge(bf);
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void defaultMergeWithNonValidatingParser() {
+		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
+		XmlBeanDefinitionReader xmlBeanDefinitionReader = new XmlBeanDefinitionReader(bf);
+		xmlBeanDefinitionReader.setValidating(false);
+		xmlBeanDefinitionReader.loadBeanDefinitions(
+				new ClassPathResource("NestedBeansElementAttributeRecursionTests-merge-context.xml", this.getClass()));
+
+		assertMerge(bf);
+	}
+
+	private void assertMerge(DefaultListableBeanFactory bf) {
 		TestBean topLevel = bf.getBean("topLevelConcreteTestBean", TestBean.class);
 		// has the concrete child bean values
 		assertThat((Iterable<String>) topLevel.getSomeList(), hasItems("charlie", "delta"));
@@ -84,6 +115,21 @@ public class NestedBeansElementAttributeRecursionTests {
 		new XmlBeanDefinitionReader(bf).loadBeanDefinitions(
 				new ClassPathResource("NestedBeansElementAttributeRecursionTests-autowire-candidates-context.xml", this.getClass()));
 
+		assertAutowireCandidates(bf);
+	}
+
+	@Test
+	public void defaultAutowireCandidatesWithNonValidatingParser() {
+		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
+		XmlBeanDefinitionReader xmlBeanDefinitionReader = new XmlBeanDefinitionReader(bf);
+		xmlBeanDefinitionReader.setValidating(false);
+		xmlBeanDefinitionReader.loadBeanDefinitions(
+				new ClassPathResource("NestedBeansElementAttributeRecursionTests-autowire-candidates-context.xml", this.getClass()));
+
+		assertAutowireCandidates(bf);
+	}
+
+	private void assertAutowireCandidates(DefaultListableBeanFactory bf) {
 		assertThat(bf.getBeanDefinition("fooService").isAutowireCandidate(), is(true));
 		assertThat(bf.getBeanDefinition("fooRepository").isAutowireCandidate(), is(true));
 		assertThat(bf.getBeanDefinition("other").isAutowireCandidate(), is(false));