[jira] [Closed] (LOG4J2-3585) Exception in Parameterized Message not logged using LocationAwareLogger API

["Marian Barton (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/LOG4J2-3585?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Marian Barton closed LOG4J2-3585.
---------------------------------

> Exception in Parameterized Message not logged using LocationAwareLogger API
> ---------------------------------------------------------------------------
>
>                 Key: LOG4J2-3585
>                 URL: https://issues.apache.org/jira/browse/LOG4J2-3585
>             Project: Log4j 2
>          Issue Type: Bug
>          Components: SLF4J Bridge
>    Affects Versions: 2.17.1
>         Environment: Windows 10, Tomcat 9, Java 8
>            Reporter: Marian Barton
>            Assignee: Piotr Karwasz
>            Priority: Major
>
> +Versions:+
>  * slf4j-api version 1.7.36
>  * log4j-core/log4j-slf4j-impl: 2.17.1
> +Action:+
> Logging a message using LocationAwareLogger.log including an exception as unused last parameter in the params array.
> +Result:+
> The message is constructed correctly but the exception is being ignored and not logged.
> +Expected:+
> According to the SLF4J FAQ, passing an exception as unused parameter in the last place should result in it being interpreted as Exception and logged as such.
> +Example:+
> {code:java}
> // Method in wrapping custom logger
> public void error(final String message, final Object... argArray) {
>     logger.log(null, FQCN, LocationAwareLogger.ERROR_INT, message, argArray, null);
> }
> // Call from another class to that method
> String someString = "insertedString";
> LOGGER.log("Test {}", someString, someException);
> // Result - no exception logged, only message
> 2022-Aug.-31 12:41:59,829 [https-openssl-nio-443-exec-4] some.Class
>   ERROR Test insertedString
> // this works though
> public void error(final String message, final Object... argArray) {
>     logger.error(message, argArray);
> }{code}
> The same call works when not using the LocationAwareLogger log method but the standard logger.error(String message, Object... argArray) method. But since I am using a wrapping logger I have to use the LocationAwareLogger interface in order to conserve the location information.
> +Possible solution:+
> I debugged a bit to try and find the issue and I might have found the problem inside the org.apache.logging.slf4j.Log4jLogger.log method:
> {code:java}
> @Override
> public void log(final Marker marker, final String fqcn, final int level, final String message, final Object[] params, Throwable throwable) {
>     final Level log4jLevel = getLevel(level);
>     final org.apache.logging.log4j.Marker log4jMarker = getMarker(marker);
>     if (!logger.isEnabled(log4jLevel, log4jMarker, message, params)) {
>         return;
>     }
>     final Message msg;
>     if (CONVERTER != null && eventLogger && marker != null && marker.contains(EVENT_MARKER)) {
>         msg = CONVERTER.convertEvent(message, params, throwable);
>     } else if (params == null) {
>         msg = new SimpleMessage(message);
>     } else {
>         msg = new ParameterizedMessage(message, params, throwable);
>         if (throwable != null) {
>             throwable = msg.getThrowable();
>         }
>     }
>     logger.logMessage(fqcn, log4jLevel, log4jMarker, msg, throwable);
> }
> {code}
> The problem here specifically being this part:
> {code:java}
> } else {
>     msg = new ParameterizedMessage(message, params, throwable);
>     if (throwable != null) {
>         throwable = msg.getThrowable();
>     }
> }
> {code}
> Log4J successfully detects this as and creates a ParameterizedMessage. This instance also correctly found the Throwable from the parameters and set it to its throwable property.
> Now I think the bug here is that the if condition is inverted. As I have no Throwable explicitly passed to this method (because it is passed via the params), it is currently null. In this case SLF4J should check if a Throwable is set and if not try to get it from the ParameterizedMessage, because there it was successfully detected inside the constructor.
> The correct implementation would therefore be:
> {code:java}
> } else {
>     msg = new ParameterizedMessage(message, params, throwable);
>     if (throwable == null) {
>         throwable = msg.getThrowable();
>     }
> }
> {code}
> If the throwable is not set here, it remains inside the ParameterizedMessage and is ignored by Log4J, as Log4J appears to only respect the explicit Throwable parameter.
> Any questions, feedback and help are/is appreciated.



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