Github user zslayton commented on a diff in the pull request:
https://github.com/apache/logging-log4j2/pull/131#discussion_r150963138
--- Diff:
log4j-core/src/main/java/org/apache/logging/log4j/core/impl/MutableLogEvent.java
---
@@ -295,7 +301,7 @@ public Message memento() {
return message;
}
final Object[] params = parameters == null ? new Object[0] :
Arrays.copyOf(parameters, parameterCount);
- return new ParameterizedMessage(messageText.toString(), params);
+ return new ParameterizedMessage(getFormat(), params);
--- End diff --
The original version of this code appears to cause nested pattern
interpretation. For example, if you created a message with the pattern `"{}"`
and the first parameter was `"json: [{}]"`, calling `memento()` on this event
would cause the fully formatted message (`json: [{}]`) to be treated as the
format for the `ParameterizedMessage` being constructed here. Because it
contains braces, the message would attempt to pull from the parameter list to
format it.
---
