Why logback lost logger when use MessageFormatter "{}"?

[Lihuanghe]

JDK: java8
os:windows
logback version: 1.2.3

This test case lost this line text logger : ">>>>>>>>this will lost<<<<<<<<<"

public class TestLogbackBug {
	private static final Logger logger = LoggerFactory.getLogger(TestLogbackBug.class);
	
	@Test
	public void test() {
		ClassA c = new ClassA();
		logger.debug("A1 =========== c: {}",c);
	}
	class ClassA {
		@Override
		public String toString() {
			
			logger.error(">>>>>>>>this will lost<<<<<<<<<");
			return "ClassA [toString()=]";
		}
	}
}

OutPut:

18:40:54.016 [main] DEBUG com.TestLogbackBug - A1 =========== c: ClassA [toString()=]

[ceki]

Which appender are you using?

[Lihuanghe]

ch.qos.logback.core.ConsoleAppender

[Lihuanghe]

ch.qos.logback.core.rolling.RollingFileAppender lost also.

[ceki]

UnsynchronizedAppenderBase has a guard protecting against recursive entry. See
UnsynchronizedAppenderBase line 66