Multiple PropertySourcesPlaceholderConfigurers do not work with placeholder defaults [SPR-10240]

[spring-issuemaster]

Paul Tomlin opened SPR-10240 and commented

While issue #14356 discusses this with respect to PropertyPlaceholderConfigurer, this issue specifically deals with the PropertySourcesPlaceholderConfigurer. I feel there is sufficient difference in their intended usage to warrant another ticket.

A PSPC will register the source with the environment, from which it may later be used by any number of locations requiring property lookup.

The problem is that the current implementation also processes the bean factory for every instance of PSPC that is configured. Like #14356, this causes placeholders which are not matched by the current environment to be replaced with their defaults, before later PSPCs have had a chance to load and populate the environment.

In this scenario @ignore-unresolvable doesn't help.

The issue really is that there's no way to register a property source, from within XML, without also having all placeholders processed.

There are multiple potential fixes for this, but I'm trying to illustrate there is a real problem.

The below test fails on bean2 because value == "Borked"

module1.greeting=Hello World

module2.greeting=Hello Universe

<context:property-placeholder location="module1.properties"/>

<bean id="bean1" class="PSPCTest$Holder">
  <property name="value" value="${module1.greeting:Borked}"/>
</bean>

<context:property-placeholder location="module2.properties"/>

<bean id="bean2" class="PSPCTest$Holder">
  <property name="value" value="${module2.greeting:Borked}"/>
</bean>

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({
	"classpath:/module1.xml",
	"classpath:/module2.xml"
})
public class PSPCTest {

	@Autowired
	@Qualifier("bean1")
	private Holder bean1;

	@Autowired
	@Qualifier("bean2")
	private Holder bean2;

	@Test
	public void testBean1Value() {
		assertEquals("Hello World", bean1.getValue());
	}
	@Test
	public void testBean2Value() {
		assertEquals("Hello Universe", bean2.getValue());
	}

	public static class Holder {
		private String value;
		public void setValue(String value) {
			this.value = value;
		}
		public String getValue() {
			return value;
		}
	}
}

---

Affects: 3.1.4, 3.2.1

Issue Links:

• #14623 Using multiple PropertyPlaceholderConfigurer breaks @Value default value behavior ("duplicates")

[spring-issuemaster]

Paul Tomlin commented

Looks like this may duplicate issue #14623

[spring-issuemaster]

Phil Webb commented

Thanks Paul, it does look like this is a duplicate so I will close this issue. Unfortunately there is not an immediately obvious fix for this so you may want to consider some of the workarounds discussed in #14623

[spring-issuemaster]

Paul Tomlin commented

Thanks Phil, I've made up a local workaround which involves using a separate namespace and a PropertySource registration mechanism.

<environment:property-source location="..."/>

The handler simply creates an EnvironmentAware BeanFactoryPostProcessor, which registers the resulting PropertySource with the environment. Seems to work sufficiently for my needs, I'll throw a Github project up when I have a chance.

[spring-issuemaster]

Phil Webb commented

Hi Paul,

I see that you recently added a link to your GitHub project on #14623. Thanks! I am sure it will help a lot of people.