Use both provided and inferred Logger coordinates

Author: ppkarwasz

log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerRegistry.java

@@ -28,6 +28,7 @@
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
+import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.MessageFactory;
 import org.apache.logging.log4j.message.ParameterizedMessageFactory;
 import org.jspecify.annotations.Nullable;
@@ -230,7 +231,10 @@ public boolean hasLogger(final String name, final Class<? extends MessageFactory
 
     /**
      * Registers the provided logger.
-     * <b>Logger name and message factory parameters are ignored</b>, those will be obtained from the logger instead.
+     * <p>
+     *   The logger will be registered using the keys provided by the {@code name} and {@code messageFactory} parameters
+     *   and the values of {@link Logger#getName()} and {@link Logger#getMessageFactory()}.
+     * </p>
      *
      * @param name a logger name
      * @param messageFactory a message factory
@@ -247,9 +251,16 @@ public void putIfAbsent(final String name, @Nullable final MessageFactory messag
         try {
             final MessageFactory effectiveMessageFactory =
                     messageFactory != null ? messageFactory : ParameterizedMessageFactory.INSTANCE;
+            // Register using the keys provided by the caller
             loggerByMessageFactoryByName
                     .computeIfAbsent(name, this::createLoggerRefByMessageFactoryMap)
                     .putIfAbsent(effectiveMessageFactory, logger);
+            // Also register using the values extracted from `logger`
+            if (!name.equals(logger.getName()) || !effectiveMessageFactory.equals(logger.getMessageFactory())) {
+                loggerByMessageFactoryByName
+                        .computeIfAbsent(logger.getName(), this::createLoggerRefByMessageFactoryMap)
+                        .putIfAbsent(logger.getMessageFactory(), logger);
+            }
         } finally {
             writeLock.unlock();
         }

log4j-core/src/main/java/org/apache/logging/log4j/core/util/internal/InternalLoggerRegistry.java

@@ -156,18 +156,24 @@ public Logger computeIfAbsent(
             // Create the logger
             logger = loggerSupplier.apply(name, messageFactory);
 
-            // Report message factory mismatches, if there is any
+            // Report name and message factory mismatch if there are any
+            final String loggerName = logger.getName();
             final MessageFactory loggerMessageFactory = logger.getMessageFactory();
             if (!loggerMessageFactory.equals(messageFactory)) {
                 StatusLogger.getLogger()
                         .error(
-                                "Newly registered logger with name `{}` and message factory `{}`, is requested to be associated with a different message factory: `{}`.\n"
+                                "Newly registered logger with name `{}` and message factory `{}`, is requested to be associated with a different name `{}` or message factory `{}`.\n"
                                         + "Effectively the message factory of the logger will be used and the other one will be ignored.\n"
                                         + "This generally hints a problem at the logger context implementation.\n"
                                         + "Please report this using the Log4j project issue tracker.",
-                                name,
+                                loggerName,
                                 loggerMessageFactory,
+                                name,
                                 messageFactory);
+                // Register logger under alternative keys
+                loggerRefByNameByMessageFactory
+                        .computeIfAbsent(loggerMessageFactory, ignored -> new HashMap<>())
+                        .putIfAbsent(loggerName, new WeakReference<>(logger));
             }
 
             // Insert the logger