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Package-private @GrpcAdvice classes fail to handle exceptions #442
Description
On current main (31de8166a178564914eab329cc5ca0d4871b6a62, 1.1.2-SNAPSHOT), an exception handler in a package-private @GrpcAdvice class is discovered successfully but fails when invoked from GrpcAdviceExceptionHandler.
For example, an application can declare the following class outside org.springframework.grpc.server.advice:
package example;
import org.springframework.grpc.server.advice.GrpcAdvice;
import org.springframework.grpc.server.advice.GrpcExceptionHandler;
import io.grpc.Status;
@GrpcAdvice
class ApplicationAdvice {
@GrpcExceptionHandler
public Status handleIllegalArgument(IllegalArgumentException exception) {
return Status.INVALID_ARGUMENT.withDescription(exception.getMessage());
}
}With this bean registered in an AnnotationConfigApplicationContext alongside GrpcAdviceDiscoverer, GrpcExceptionHandlerMethodResolver, and GrpcAdviceExceptionHandler, handling new IllegalArgumentException("bad argument") should return INVALID_ARGUMENT with description bad argument.
Instead, it returns INTERNAL with description There was a server error trying to handle an exception. The underlying cause is IllegalAccessException: the framework cannot access a public method whose declaring class is not public and is in another package.
Changing only the advice class to public makes the same test pass. The existing package-private advice fixture is in the framework implementation's package, so it does not exercise this access boundary.
The failure occurs at mappedMethod.invoke(...) in GrpcAdviceExceptionHandler.invokeMappedMethodSafely. Making the method accessible before invoking it appears sufficient to preserve the current exception matching and return-value handling. Neither annotation currently documents a public-class requirement.
The accompanying test patch adds a public and a package-private advice fixture in another package. With Java 25, the existing six GrpcAdviceExceptionHandlerTests tests and the public-class control pass; the package-private-class test fails with expected: INVALID_ARGUMENT, but was: INTERNAL.
The reproduction exercises the real Spring context and exception handler, without requiring a running gRPC server. It can be run with:
./mvnw -pl spring-grpc-core -am \
-Dtest=GrpcAdviceExceptionHandlerTests \
-Dsurefire.failIfNoSpecifiedTests=false testRegression test patch
Save the following diff as advice-visibility.patch and apply it with git apply advice-visibility.patch at the repository root before running the command above.
diff --git a/spring-grpc-core/src/test/java/org/springframework/grpc/server/advice/GrpcAdviceExceptionHandlerTests.java b/spring-grpc-core/src/test/java/org/springframework/grpc/server/advice/GrpcAdviceExceptionHandlerTests.java
index 1360b2f..122213f 100644
--- a/spring-grpc-core/src/test/java/org/springframework/grpc/server/advice/GrpcAdviceExceptionHandlerTests.java
+++ b/spring-grpc-core/src/test/java/org/springframework/grpc/server/advice/GrpcAdviceExceptionHandlerTests.java
@@ -26,6 +26,7 @@ import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
+import org.springframework.grpc.server.advice.support.AdviceVisibilitySamples;
import io.grpc.Metadata;
import io.grpc.Status;
@@ -36,9 +37,32 @@ import io.grpc.StatusRuntimeException;
* Tests for {@link GrpcAdviceExceptionHandler}.
*
* @author Oleksandr Shevchenko
+ * @author Jialin Chen
*/
class GrpcAdviceExceptionHandlerTests {
+ @Test
+ void handlesExceptionInPublicAdviceFromAnotherPackage() {
+ assertAdviceHandlesException(AdviceVisibilitySamples.PublicAdvice.class);
+ }
+
+ @Test
+ void handlesExceptionInPackagePrivateAdviceFromAnotherPackage() {
+ assertAdviceHandlesException(AdviceVisibilitySamples.packagePrivateAdviceType());
+ }
+
+ private void assertAdviceHandlesException(Class<?> adviceType) {
+ try (AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(adviceType,
+ GrpcAdviceDiscoverer.class, GrpcExceptionHandlerMethodResolver.class,
+ GrpcAdviceExceptionHandler.class)) {
+ GrpcAdviceExceptionHandler handler = context.getBean(GrpcAdviceExceptionHandler.class);
+ StatusException result = handler.handleException(new IllegalArgumentException("bad argument"));
+ assertThat(result).isNotNull();
+ assertThat(result.getStatus().getCode()).isEqualTo(Status.Code.INVALID_ARGUMENT);
+ assertThat(result.getStatus().getDescription()).isEqualTo("bad argument");
+ }
+ }
+
@Test
void handlesExceptionWithMappedHandler() {
try (AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(TestConfig.class)) {
diff --git a/spring-grpc-core/src/test/java/org/springframework/grpc/server/advice/support/AdviceVisibilitySamples.java b/spring-grpc-core/src/test/java/org/springframework/grpc/server/advice/support/AdviceVisibilitySamples.java
new file mode 100644
index 0000000..4925bc7
--- /dev/null
+++ b/spring-grpc-core/src/test/java/org/springframework/grpc/server/advice/support/AdviceVisibilitySamples.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2026-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.grpc.server.advice.support;
+
+import org.springframework.grpc.server.advice.GrpcAdvice;
+import org.springframework.grpc.server.advice.GrpcExceptionHandler;
+
+import io.grpc.Status;
+
+/**
+ * Advice fixtures in a different package from the exception handler implementation.
+ *
+ * @author Jialin Chen
+ */
+public final class AdviceVisibilitySamples {
+
+ private AdviceVisibilitySamples() {
+ }
+
+ public static Class<?> packagePrivateAdviceType() {
+ return PackagePrivateAdvice.class;
+ }
+
+ @GrpcAdvice
+ public static class PublicAdvice {
+
+ @GrpcExceptionHandler
+ public Status handleIllegalArgument(IllegalArgumentException exception) {
+ return Status.INVALID_ARGUMENT.withDescription(exception.getMessage());
+ }
+
+ }
+
+ @GrpcAdvice
+ static class PackagePrivateAdvice {
+
+ @GrpcExceptionHandler
+ public Status handleIllegalArgument(IllegalArgumentException exception) {
+ return Status.INVALID_ARGUMENT.withDescription(exception.getMessage());
+ }
+
+ }
+
+}If you agree that this should be fixed, I’d be happy to work on a fix and submit a PR.
Activity
dsyer commentedon Oct 12, 2026
Happy to look at the patch.
dhanush080607 commentedon Oct 14, 2026
Thanks! I'll work on the fix, add regression coverage for package-private
@GrpcAdviceclasses in a different package, and run the relevant tests before submitting a PR.CCCLL commentedon Oct 15, 2026
Thanks for offering to help, @dhanush080607. I have now submitted the fix and regression tests in #443. To avoid duplicate work, please hold off on a separate implementation. Feedback on the PR is welcome.