[LOG4J2-3264] MapLookup should lookup MapMessage before properties

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.17.1
• Assignee: Carter Kozak
• Reporter: Yanming Zhou
• Created: 21/Dec/21 01:00
• Updated: 07/Jan/22 19:58
• Resolved: 23/Dec/21 17:46

Description

According to https://logging.apache.org/log4j/2.x/manual/lookups.html#MapLookup

Note that when used this way a value for "type" should be declared in the properties declaration to provide a default value in case the message is not a MapMessage or the MapMessage does not contain the key.

If "type" is present with a MapMessage, then it will be picked not default value in the properties declaration, but the code show that the default value is always picked.
https://github.com/apache/logging-log4j2/blob/20f9a97dbe5928c3b5077bcdd2a22ac92e941655/log4j-core/src/main/java/org/apache/logging/log4j/core/lookup/MapLookup.java#L89-L104

Issue Links

• links to: GitHub Pull Request #646