Minecrell/TerminalConsoleAppender

Race condition when logging message while JLine is not reading input

Closed this issue · 1 comments

stephan-gh commented

Related to PaperMC/Waterfall#188, PaperMC/Paper#1093

There is a possible race condition when logging a message using TerminalConsoleAppender, while the JLine LineReader is changing state (e.g. shortly before it starts reading or shortly after).

This results in an error when re-drawing the input prompt:

TerminalConsoleAppender/src/main/java/net/minecrell/terminalconsole/TerminalConsoleAppender.java

Lines 263 to 267 in b105359

// Draw the prompt line again if a reader is available
reader.callWidget(LineReader.CLEAR);
terminal.writer().print(getLayout().toSerializable(event));
reader.callWidget(LineReader.REDRAW_LINE);
reader.callWidget(LineReader.REDISPLAY); 

ERROR An exception occurred processing Appender TerminalConsole java.lang.IllegalStateException
	at org.jline.reader.impl.LineReaderImpl.callWidget(LineReaderImpl.java:651)
	at net.minecrell.terminalconsole.TerminalConsoleAppender.append(TerminalConsoleAppender.java:265)
	at org.apache.logging.log4j.core.config.AppenderControl.tryCallAppender(AppenderControl.java:156)
	at org.apache.logging.log4j.core.config.AppenderControl.callAppender0(AppenderControl.java:129)
	at org.apache.logging.log4j.core.config.AppenderControl.callAppenderPreventRecursion(AppenderControl.java:120)
	at org.apache.logging.log4j.core.config.AppenderControl.callAppender(AppenderControl.java:84)
	at org.apache.logging.log4j.core.config.LoggerConfig.callAppenders(LoggerConfig.java:448)