When we create a custom log recorder, if we set the levels from higher to lower, it correctly takes effect. But if we do the other way round, set the level from lower to higher, it doesn't reflect correctly – still partially stays on the lowest level.

 

Why say partially ?

	
the level reflected by LOGGER.getLevel() stays at the lowest. Lets say you changed the level from FINEST to FINE (or INFO), the returned value of LOGGER.getLevel() is still FINEST.
	
however logging statements like LOGGER.log(..) or LOGGER.finest(..) (and others) correctly see the level. Thus there are no log messages seen for lower level logging statements than the currently set level.



 

The level gets correctly set,

	
if we manually set it from the Log Levels page.
	
if we delete the log recorder and recreate it at the desired level.
	
or, restart the Jenkins controller.



 

This particularly causes bug in code like,

if (LOGGER.isLoggable(Level.FINER)) {
    LOGGER.finer("Detailed debug info with parameters.");
} else {
    LOGGER.info("Intermittent issue detected. Monitor if it persists."); 
} 

Once we changed from say FINER to INFO or to any higher level, the code still goes into if block whereas it was expected to go into the else block. Although it goes into the if block, it doesn't log anything – because inside the LOGGER.finer(...) method or LOGGER.log(..) method the level is correctly evaluated.
 
This behavior is quite confusing and appears to be incorrect memory state of loggers (the `log/<my-logger>.xml` file is correct) - as the issues fixes itself upon controller restart.
Steps to Reproduce
Reproduction can be done using this minimal example
https://github.com/gbhat618/minimal/blob/main/src/main/java/io/jenkins/plugins/sample/LogRecorderLevelDebug.java
Run the minimal plugin with,

mvn hpi:run


Verify the correct behavior

	
create a log recorder for class LogRecorderLevelDebug; the periodic work runs every 5s, so you will start seeing info logs. At the beginning the level will be reported null. It is expected.
	
try to change from INFO to FINE and then from FINE to FINEST. You will see all the logs correctly.
	
Also keep noticing that the LogRecorderLevelDebug has appeared in the Log Levels page and it is correctly reflecting the levels as changed in the configure.

Verify the incorrect behavior

	
change the recorder level from FINEST to FINE; notice the level is reported incorrectly as still FINEST; however the actual FINEST log is not coming, only the FINE and INFO are coming. (the actual FINEST log entry would be FINEST level log - which is missing here)

Feb 21, 2025 8:34:25 AM INFO io.jenkins.plugins.sample.LogRecorderLevelDebug doRun
Current log level: FINEST
Feb 21, 2025 8:34:25 AM FINE io.jenkins.plugins.sample.LogRecorderLevelDebug
FINE level log inside the if block
Feb 21, 2025 8:34:25 AM INFO io.jenkins.plugins.sample.LogRecorderLevelDebug doRun
INFO level log inside the if block




	
change the recorder from FINE to INFO; notice only the INFO entry from within the if block is coming; while expected was the entry from the else block

Feb 21, 2025 8:37:45 AM INFO io.jenkins.plugins.sample.LogRecorderLevelDebug doRun
Current log level: FINEST
Feb 21, 2025 8:37:45 AM INFO io.jenkins.plugins.sample.LogRecorderLevelDebug doRun
INFO level log inside the if block




	
During this time in the Log Levels Page you will see that the level for LogRecorderLevelDebug is still set as FINEST, and it is not reflecting the recorder's level. It was reflecting when we were changing the level from higher to lower, it is not reflecting when changing from lower to higher.




Description
Screenshot


The Log Level that referred in the above notes; find here



Example of Log Level incorrectly showing the FINEST level even when the recorder is changed to higher level INFO