Authorization failure does not clear current Authentication

Closes gh-409

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/web/OAuth2AuthorizationEndpointFilter.java

@@ -31,7 +31,6 @@ import org.springframework.http.MediaType;
 import org.springframework.security.authentication.AuthenticationManager;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.core.AuthenticationException;
-import org.springframework.security.core.context.SecurityContextHolder;
 import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
 import org.springframework.security.oauth2.core.OAuth2Error;
 import org.springframework.security.oauth2.core.endpoint.OAuth2AuthorizationResponse;
@@ -165,7 +164,6 @@ public final class OAuth2AuthorizationEndpointFilter extends OncePerRequestFilte
 					request, response, authorizationCodeRequestAuthenticationResult);
 
 		} catch (OAuth2AuthenticationException ex) {
-			SecurityContextHolder.clearContext();
 			this.authenticationFailureHandler.onAuthenticationFailure(request, response, ex);
 		}
 	}

oauth2-authorization-server/src/test/java/org/springframework/security/oauth2/server/authorization/web/OAuth2AuthorizationEndpointFilterTests.java

@@ -41,13 +41,13 @@ import org.springframework.security.authentication.TestingAuthenticationToken;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.core.context.SecurityContext;
 import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.oauth2.core.OAuth2AuthorizationCode;
 import org.springframework.security.oauth2.core.OAuth2Error;
 import org.springframework.security.oauth2.core.OAuth2ErrorCodes;
 import org.springframework.security.oauth2.core.endpoint.OAuth2AuthorizationResponseType;
 import org.springframework.security.oauth2.core.endpoint.OAuth2ParameterNames;
 import org.springframework.security.oauth2.core.endpoint.PkceParameterNames;
 import org.springframework.security.oauth2.core.oidc.OidcScopes;
-import org.springframework.security.oauth2.core.OAuth2AuthorizationCode;
 import org.springframework.security.oauth2.server.authorization.authentication.OAuth2AuthorizationCodeRequestAuthenticationException;
 import org.springframework.security.oauth2.server.authorization.authentication.OAuth2AuthorizationCodeRequestAuthenticationToken;
 import org.springframework.security.oauth2.server.authorization.client.RegisteredClient;
@@ -266,6 +266,7 @@ public class OAuth2AuthorizationEndpointFilterTests {
 
 		assertThat(response.getStatus()).isEqualTo(HttpStatus.FOUND.value());
 		assertThat(response.getRedirectedUrl()).isEqualTo("https://example.com?error=errorCode&error_description=errorDescription&error_uri=errorUri&state=state");
+		assertThat(SecurityContextHolder.getContext().getAuthentication()).isSameAs(this.principal);
 	}
 
 	@Test