Logback refactored the inclusion of configuration snippets in version 1.5.5. (For details see this commit and this comment in logback repo.)
Updating logback from <= 1.5.4 to >= 1.5.5 breaks <springProperty> when used within an included configuration snippet.

Example

A simple spring boot application using logback.
A prefix for log messages is configured in the environment using <springProperty>.

logback.xml

<configuration> <include resource="included.xml" optional="false" /> <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"> <encoder> <pattern>${prefix} %msg %n</pattern> </encoder> </appender> <root level="DEBUG"> <appender-ref ref="STDOUT" /> </root> </configuration> 

included.xml

<included> <!-- works with 1.5.4, broken with 1.5.5 and 1.5.6 --> <springProperty name="prefix" source="prefix" scope="context" defalultValue="[default prefix]" /> </included> 

in application.properties

prefix = [prefix from env] 

The expected log output is "[prefix from env] ..." but acutaly is "prefix_IS_UNDEFINED ...".

Cause

Since the refactoring a new instance of JoranConfigurator is created when an inclusion is processed.

new code in JoranConfigurator

 private JoranConfigurator makeAnotherInstance() { JoranConfigurator jc = new JoranConfigurator(); jc.setContext(this.context); return jc; } public void buildModelInterpretationContext() { super.buildModelInterpretationContext(); this.modelInterpretationContext.setConfiguratorSupplier(() -> { return this.makeAnotherInstance(); }); } 

The new instance is currently not a SpringBootJoranConfigurator but a simple JoranConfigurator that does not know about springs extensions (e.g. <springProperty>).
Therefore <springProfile> might be affected as well.

Fix

Overriding buildModelInterpretationContext() in SpringBootJoranConfigurator to provide an instance of SpringBootJoranConfigurator with the same LoggingInitializationContext.