Short circuit @Value injection when using a source already covered by ConfigurationPropertySourcesPropertySource

[ShijunDeng]

spring-boot/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/ConfigurationPropertySourcesPropertySource.java

Line 33 in aaad772

class ConfigurationPropertySourcesPropertySource extends PropertySource<Iterable<ConfigurationPropertySource>>

In Springboot application，ConfigurationPropertySourcesPropertySource is added to the environment and as first element, the ConfigurationPropertySourcesPropertySource acts as a facade over the existing property sources.

When handling @Value annotation, org.springframework.core.env.PropertySourcesPropertyResolver#getProperty will be called.
If the property is found then ConfigurationPropertySourcesPropertySource will return the result. otherwise, PropertySourcesPropertyResolver continues to check all subsequent sources. This is a little inefficient for any source that has already been check via ConfigurationPropertySourcesPropertySource.

[philwebb]

I think we may have fixed this already with #17400 (commit 6ad100e) which was added to Spring Boot 2.5. @ShijunDeng Can you check that you're using Spring Boot 2.5 or above? If you're finding an issue with that version could you please please provide a sample that shows the problem.

[ShijunDeng]

New similar problem with ConfigurationPropertySourcesPropertyResolver in #17400. My Spring Boot version is 2.5.6.

ConfigurationPropertySourcesPropertyResolver is Spring boot source code, but org.springframework.core.env.PropertySourcesPropertyResolver#getProperty is defined in spring-core. The @Value processor use PropertySourcesPropertyResolver. Set a breakpoint in method org.springframework.core.env.PropertySourcesPropertyResolver#getProperty, it's easy to see that PropertySourcesPropertyResolver continues to check all subsequent sources when not found key in ConfigurationPropertySourcesPropertySource.

as the screenshort below:

PropertySourcesPropertyResolver continues to check subsequent source such as SimpleCommandLinePropertySource {name='commandLineArgs'}

[ShijunDeng]

@philwebb ，hi，How is it going ？

[philwebb]

I need to dig a bit more, but I suspect this resolver is being used which doesn't support the short-circuiting.