Fix authRequest field to AuthenticationException via setter

Signed-off-by: amm0124 <amm0124@naver.com>

Author: amm0124

core/src/main/java/org/springframework/security/core/AuthenticationException.java

@@ -18,6 +18,8 @@
 
 import java.io.Serial;
 
+import org.springframework.util.Assert;
+
 /**
  * Abstract superclass for all exceptions related to an {@link Authentication} object
  * being invalid for whatever reason.
@@ -29,7 +31,15 @@ public abstract class AuthenticationException extends RuntimeException {
 	@Serial
 	private static final long serialVersionUID = 2018827803361503060L;
 
-	private final Authentication authRequest;
+	/**
+	 * The {@link Authentication} object representing the failed authentication attempt.
+	 * <p>
+	 * This field captures the authentication request that was attempted but ultimately
+	 * failed, providing critical information for diagnosing the failure and facilitating
+	 * debugging. If set, the value must not be null.
+	 * </p>
+	 */
+	private Authentication authRequest;
 
 	/**
 	 * Constructs an {@code AuthenticationException} with the specified message and root
@@ -52,8 +62,29 @@ public AuthenticationException(String msg) {
 		this.authRequest = null;
 	}
 
+	/**
+	 * Constructs an {@code AuthenticationException} with the specified message and root
+	 * cause.
+	 * @param msg the detail message
+	 * @param authRequest details about the failed authentication request
+	 */
 	public AuthenticationException(String msg, Authentication authRequest) {
 		super(msg);
+		Assert.notNull(authRequest, "AuthRequest cannot be null");
+	}
+
+	/**
+	 * Sets the {@link Authentication} object representing the failed authentication
+	 * attempt.
+	 * <p>
+	 * This method allows the injection of the authentication request that resulted in a
+	 * failure. The provided {@code authRequest} should not be null if set.
+	 * </p>
+	 * @param authRequest the authentication request associated with the failed
+	 * authentication attempt.
+	 */
+	public void setAuthRequest(Authentication authRequest) {
+		Assert.notNull(authRequest, "AuthRequest cannot be null");
 		this.authRequest = authRequest;
 	}