String values with an unmatched right curly brace } drop the brace and subsequent characters

[philsttr]

In logback xml, when configuring string values with an unmatched right curly brace, the right curly brace and everything after it is dropped.

An easy way to see this behavior is to configure the PatternLayoutEncoder's pattern as follows:

<configuration>
    <appender name="console" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">

            <pattern>%m}This will not appear in the pattern</pattern>

        </encoder>
    </appender>

    <root>
        <appender-ref ref="console"/>
    </root>
</configuration>

And run the following class:

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Main {
    private static Logger LOGGER = LoggerFactory.getLogger(Main.class);

    public static void main(String[] args) {
        LOGGER.info("Hello world!");
    }
}

The actual output will be:

Hello world!

The expected output is:

Hello world!}This will not appear in the pattern

This is a contrived example, but I chose it because it is very clear.

The actual use case was discovered here logfellow/logstash-logback-encoder#1009