From 2aec4d84de361be26d20a3a6d5dd05cad3f73953 Mon Sep 17 00:00:00 2001
From: DavesMan <davesman@centrum.cz>
Date: Mon, 24 Jan 2022 08:18:24 +0100
Subject: [PATCH] SLF4J-165 Handling of unknown (custom) priorities is
 different than in log4j (throwing an IllegalStateException than using the
 effective level of the given Priority / Level / Category)

---
 log4j-over-slf4j/src/main/java/org/apache/log4j/Category.java | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/log4j-over-slf4j/src/main/java/org/apache/log4j/Category.java b/log4j-over-slf4j/src/main/java/org/apache/log4j/Category.java
index fc8b50c20..5edde37f5 100644
--- a/log4j-over-slf4j/src/main/java/org/apache/log4j/Category.java
+++ b/log4j-over-slf4j/src/main/java/org/apache/log4j/Category.java
@@ -323,7 +323,8 @@ private int priorityToLevelInt(Priority p) {
         case Priority.FATAL_INT:
             return LocationAwareLogger.ERROR_INT;
         default:
-            throw new IllegalStateException("Unknown Priority " + p);
+            slf4jLogger.warn("Unknown Priority " + p);
+            return LocationAwareLogger.TRACE_INT;
         }
     }