Hello,

When i reading the spring-boot reference, it seems the below description is wrong.

Please see below details for your reproduce. 1.The reference document url is https://docs.spring.io/spring-boot/docs/3.1.6/reference/html/features.html#features.logging.custom-log-configuration 2.The wrong section as below: If you want to use a placeholder in a logging property, you should use Spring Boot’s syntax and not the syntax of the underlying framework. Notably, if you use Logback, you should use : as the delimiter between a property name and its default value and not use :-. 3.What's wrong? Wrong: Notably, if you use Logback, you should use : as the delimiter between a property name and its default value and not use :-. Correct: Notably, if you use Logback, you should use :- as the delimiter between a property name and its default value and not use :.

Since the logback document says, it default value delimitor is ":-", for exmaple, "${aName:-golden}". Please see this for more detail: https://logback.qos.ch/manual/configuration.html#defaultValuesForVariables And also, the spring boot documents says, it default value delimitor is ":", for example, ${username:Unknown}. Please see this for more detail: https://docs.spring.io/spring-boot/docs/3.1.6/reference/html/features.html#features.external-config.files.property-placeholders

Based on above documents, so i think the default value delimitor description is wrong on spring-boot reference.

Please help to check, and fix if it should be fixed. Thanks from a developer which using spring boot.

Comment From: wilkinsona

I think the documentation is correct. It's referring to properties that are configured in application.properties or application.yaml. They are resolved using the environment before being passed into Logback. This resolution is performed entirely by Spring so Logback's syntax is not relevant.

If you are configuring Logback using logback.xml or hogback-spring.xml then you should use the :- delimiter as this is a Logback configuration file and the values are passed directly to Logback. That's not what the linked section of the documentation is about though.