log messages with last parameter being a Throwable log a warning

[flocsy]

Description

String foo = "FOO";
try {
throw new Exception("test");
} catch {Throwable t) {
logger.info("foo: {}", foo, t);
}

creates a warning:
found 1 argument placeholders, but provided 2 for pattern foo: {}

Configuration

Version: 2.24.0

Operating system: Linux, MacOS

JDK: coretto 21.0.7

Logs

found 1 argument placeholders, but provided 2 for pattern `foo: {}`

Reproduction

This was working in versions, up-to (including) 2.23.1, and is broken since version 2.24.0

It looks like it's related to #2380

[ppkarwasz]

Hi @flocsy,

Thanks for the report. I couldn’t reproduce the issue in either 2.24.0 or 2.24.3. It’s likely caused by a non-standard setup.

Could you share a minimal reproducible example or more details about your environment?

A few things that might be relevant:

• A custom MessageFactory configured via log4j2.messageFactory
• Use of a different logging API—if so, which bridge to Log4j API are you using? I tested with SLF4J 2 + log4j-slf4j2-impl and didn’t see the issue.