[LOG4J2-2032] Curly braces in parameters are treated as placeholders

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.8.2, 2.9.0, 2.10.0
• Fix Version/s: 2.11.1, 3.0.0
• Component/s: Appenders, Layouts

Environment

Tested on Windows and Linux.

java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)

• Flags: Important
• Assignee: Carter Kozak
• Reporter: Kostiantyn Shchepanovskyi
• Created: 05/Sep/17 14:43
• Updated: 30/May/18 16:31
• Resolved: 07/Apr/18 23:22

Description

When logging event parameter contains two consecutive opening and closing curly braces - for example {} in the middle of parameter, they are treated as a placeholder and are substituted by provided parameters starting from index zero.

I suspect that it affects only async loggers.

My configuration:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
    <Appenders>
        <Console name="console" target="SYSTEM_OUT">
            <PatternLayout>
                <pattern>%level{length=1} %date{MMdd-HHmm:ss,SSS} %logger{1.} %message %X [%thread]%n
                </pattern>
            </PatternLayout>
        </Console>
        <Async name="asyncFile">
            <AppenderRef ref="console"/>
        </Async>
    </Appenders>
    <Loggers>
        <Root level="info">
            <AppenderRef ref="asyncFile"/>
        </Root>
    </Loggers>
</Configuration>

Test:

package com.playtech.live.platform.core.service;

import org.junit.jupiter.api.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Log4jCurlyBracesInParameterTest {

    private static final Logger LOGGER = LoggerFactory.getLogger(Log4jCurlyBracesInParameterTest.class);

    @Test
    void messageWithCurlyBracesInParameter() {
        LOGGER.info("Text containing curly braces: {}", "Curly{}");
        LOGGER.info("Normal text: {}, text containing curly braces {}", "Normal", "Curly{}");
    }
}

Expected output:

I 0905-1731:01,018 c.p.l.p.c.s.Log4jCurlyBracesInParameterTest Text containing curly braces: Curly{} {} [main]
I 0905-1731:01,033 c.p.l.p.c.s.Log4jCurlyBracesInParameterTest Normal text: Normal, text containing curly braces Curly{} {} [main]

Actual output:

I 0905-1731:01,018 c.p.l.p.c.s.Log4jCurlyBracesInParameterTest Text containing curly braces: CurlyCurly{} {} [main]
I 0905-1731:01,033 c.p.l.p.c.s.Log4jCurlyBracesInParameterTest Normal text: Normal, text containing curly braces CurlyNormal {} [main]

Issue Links

• is duplicated by: LOG4J2-2345 JsonLayout logs malformed if toString() contains empty curly braces {}
• links to: GitHub Pull Request #147