Experiment 3 : Reproduce issue with Error thrown in AsyncInterceptor

The call finishes successfully, but since the throwable is not a RuntimeException, the
diagnostic message gets buried in suppresed exception list. Therefore I think it would
be good to keep the first exception as a cause.

core-client/src/main/java/org/glassfish/jersey/client/InvocationInterceptorStages.java

@@ -607,6 +607,8 @@ private static RuntimeException suppressExceptions(Deque<Throwable> throwables)
         for (Throwable throwable : throwables) {
             processingException.addSuppressed(throwable);
         }
+        // add first throwable as cause for some guidance
+        processingException.initCause(throwables.peek());
         return processingException;
     }
 }

tests/integration/microprofile/rest-client/src/test/java/org/glassfish/jersey/restclient/AsyncInterceptorTest.java

@@ -0,0 +1,195 @@
+/*
+ *    DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ *    Copyright (c) [2019] Payara Foundation and/or its affiliates. All rights reserved.
+ *
+ *    The contents of this file are subject to the terms of either the GNU
+ *    General Public License Version 2 only ("GPL") or the Common Development
+ *    and Distribution License("CDDL") (collectively, the "License").  You
+ *    may not use this file except in compliance with the License.  You can
+ *    obtain a copy of the License at
+ *    https://github.com/payara/Payara/blob/master/LICENSE.txt
+ *    See the License for the specific
+ *    language governing permissions and limitations under the License.
+ *
+ *    When distributing the software, include this License Header Notice in each
+ *    file and include the License file at glassfish/legal/LICENSE.txt.
+ *
+ *    GPL Classpath Exception:
+ *    The Payara Foundation designates this particular file as subject to the "Classpath"
+ *    exception as provided by the Payara Foundation in the GPL Version 2 section of the License
+ *    file that accompanied this code.
+ *
+ *    Modifications:
+ *    If applicable, add the following below the License Header, with the fields
+ *    enclosed by brackets [] replaced by your own identifying information:
+ *    "Portions Copyright [year] [name of copyright owner]"
+ *
+ *    Contributor(s):
+ *    If you wish your version of this file to be governed by only the CDDL or
+ *    only the GPL Version 2, indicate your decision by adding "[Contributor]
+ *    elects to include this software in this distribution under the [CDDL or GPL
+ *    Version 2] license."  If you don't indicate a single choice of license, a
+ *    recipient has the option to distribute your version of this file under
+ *    either the CDDL, the GPL Version 2 or to extend the choice of license to
+ *    its licensees as provided above.  However, if you add GPL Version 2 code
+ *    and therefore, elected the GPL Version 2 license, then the option applies
+ *    only if the new code is made subject to such option by the copyright
+ *    holder.
+ */
+
+package org.glassfish.jersey.restclient;
+
+import org.eclipse.microprofile.rest.client.RestClientBuilder;
+import org.eclipse.microprofile.rest.client.ext.AsyncInvocationInterceptor;
+import org.eclipse.microprofile.rest.client.ext.AsyncInvocationInterceptorFactory;
+import org.glassfish.jersey.server.ResourceConfig;
+import org.glassfish.jersey.test.JerseyTest;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestName;
+
+import javax.ws.rs.client.ClientRequestContext;
+import javax.ws.rs.client.ClientRequestFilter;
+import javax.ws.rs.core.Application;
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+import static org.junit.Assert.assertTrue;
+import static org.testng.AssertJUnit.assertEquals;
+
+public class AsyncInterceptorTest extends JerseyTest {
+    static ThreadLocal<String> trace = new ThreadLocal<>();
+
+    @Rule
+    public TestName name = new TestName();
+
+    @Override
+    protected Application configure() {
+        return new ResourceConfig(AsyncResourceImpl.class);
+    }
+
+    @Test
+    public void testPropagation() throws URISyntaxException, InterruptedException, ExecutionException, TimeoutException {
+        FailsOn mode = FailsOn.NEVER;
+        AsyncResource client = createClient(mode);
+
+        trace.set(name.getMethodName());
+        CompletableFuture<String> future = client.asyncCall().toCompletableFuture();
+        String result = future.get(1, TimeUnit.SECONDS);
+        assertEquals(name.getMethodName(), result);
+    }
+
+    @Test
+    public void testFailingOnPrepare() throws URISyntaxException, InterruptedException, ExecutionException, TimeoutException {
+        FailsOn mode = FailsOn.PREPARE;
+        AsyncResource client = createClient(mode);
+
+        trace.set(name.getMethodName());
+        CompletableFuture<String> future = client.asyncCall().toCompletableFuture();
+        try {
+            String result = future.get(1, TimeUnit.SECONDS);
+        } catch (ExecutionException e) {
+            // that's what we expect
+            Throwable cause = e.getCause().getCause();
+            assertEquals("Fails on prepare", cause.getMessage());
+        }
+        assertTrue(future.isCompletedExceptionally());
+    }
+
+    @Test
+    public void testFailingOnApply() throws URISyntaxException, InterruptedException, ExecutionException, TimeoutException {
+        FailsOn mode = FailsOn.APPLY;
+        AsyncResource client = createClient(mode);
+
+        trace.set(name.getMethodName());
+        CompletableFuture<String> future = client.asyncCall().toCompletableFuture();
+        try {
+            String result = future.get(1, TimeUnit.SECONDS);
+        } catch (ExecutionException e) {
+            // that's what we expect
+            Throwable cause = e.getCause().getCause();
+            assertEquals("Fails on apply", cause.getMessage());
+        }
+        assertTrue(future.isCompletedExceptionally());
+    }
+
+    @Test
+    public void testFailingOnRemove() throws URISyntaxException, InterruptedException, ExecutionException, TimeoutException {
+        FailsOn mode = FailsOn.REMOVE;
+        AsyncResource client = createClient(mode);
+
+        trace.set(name.getMethodName());
+        CompletableFuture<String> future = client.asyncCall().toCompletableFuture();
+        try {
+            String result = future.get(1, TimeUnit.SECONDS);
+        } catch (ExecutionException e) {
+            // that's what we expect
+            Throwable cause = e.getCause().getCause();
+            assertEquals("Fails on remove", cause.getMessage());
+        }
+        assertTrue(future.isCompletedExceptionally());
+    }
+
+    private AsyncResource createClient(FailsOn mode) throws URISyntaxException {
+        return RestClientBuilder.newBuilder()
+                .baseUri(new URI("http://localhost:9998"))
+                .register(interceptor(mode))
+                .register(TracePropagator.class)
+                .build(AsyncResource.class);
+    }
+
+    private AsyncInvocationInterceptorFactory interceptor(FailsOn mode) {
+        return () -> new FailingInterceptor(mode);
+    }
+
+    enum FailsOn {
+        NEVER, PREPARE, APPLY, REMOVE
+    }
+
+    static class TracePropagator implements ClientRequestFilter {
+
+        @Override
+        public void filter(ClientRequestContext requestContext) throws IOException {
+            requestContext.getHeaders().add("trace", trace.get());
+        }
+    }
+
+    static class FailingInterceptor implements AsyncInvocationInterceptor {
+        private final FailsOn mode;
+        private String traceValue;
+
+        FailingInterceptor(FailsOn mode) {
+            this.mode = mode;
+        }
+
+        @Override
+        public void prepareContext() {
+            if (mode == FailsOn.PREPARE) {
+                throw new AssertionError("Fails on prepare");
+            }
+            traceValue = trace.get();
+        }
+
+        @Override
+        public void applyContext() {
+            if (mode == FailsOn.APPLY) {
+                throw new AssertionError("Fails on apply");
+            }
+            trace.set(traceValue);
+        }
+
+        @Override
+        public void removeContext() {
+            if (mode == FailsOn.REMOVE) {
+                throw new AssertionError("Fails on remove");
+            }
+            trace.remove();
+        }
+    }
+}

tests/integration/microprofile/rest-client/src/test/java/org/glassfish/jersey/restclient/AsyncResource.java

@@ -0,0 +1,52 @@
+/*
+ *    DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ *    Copyright (c) [2019] Payara Foundation and/or its affiliates. All rights reserved.
+ *
+ *    The contents of this file are subject to the terms of either the GNU
+ *    General Public License Version 2 only ("GPL") or the Common Development
+ *    and Distribution License("CDDL") (collectively, the "License").  You
+ *    may not use this file except in compliance with the License.  You can
+ *    obtain a copy of the License at
+ *    https://github.com/payara/Payara/blob/master/LICENSE.txt
+ *    See the License for the specific
+ *    language governing permissions and limitations under the License.
+ *
+ *    When distributing the software, include this License Header Notice in each
+ *    file and include the License file at glassfish/legal/LICENSE.txt.
+ *
+ *    GPL Classpath Exception:
+ *    The Payara Foundation designates this particular file as subject to the "Classpath"
+ *    exception as provided by the Payara Foundation in the GPL Version 2 section of the License
+ *    file that accompanied this code.
+ *
+ *    Modifications:
+ *    If applicable, add the following below the License Header, with the fields
+ *    enclosed by brackets [] replaced by your own identifying information:
+ *    "Portions Copyright [year] [name of copyright owner]"
+ *
+ *    Contributor(s):
+ *    If you wish your version of this file to be governed by only the CDDL or
+ *    only the GPL Version 2, indicate your decision by adding "[Contributor]
+ *    elects to include this software in this distribution under the [CDDL or GPL
+ *    Version 2] license."  If you don't indicate a single choice of license, a
+ *    recipient has the option to distribute your version of this file under
+ *    either the CDDL, the GPL Version 2 or to extend the choice of license to
+ *    its licensees as provided above.  However, if you add GPL Version 2 code
+ *    and therefore, elected the GPL Version 2 license, then the option applies
+ *    only if the new code is made subject to such option by the copyright
+ *    holder.
+ */
+
+package org.glassfish.jersey.restclient;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import java.util.concurrent.CompletionStage;
+
+@Path("async")
+public interface AsyncResource {
+
+    @GET
+    CompletionStage<String> asyncCall();
+}

tests/integration/microprofile/rest-client/src/test/java/org/glassfish/jersey/restclient/AsyncResourceImpl.java

@@ -0,0 +1,54 @@
+/*
+ *    DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ *    Copyright (c) [2019] Payara Foundation and/or its affiliates. All rights reserved.
+ *
+ *    The contents of this file are subject to the terms of either the GNU
+ *    General Public License Version 2 only ("GPL") or the Common Development
+ *    and Distribution License("CDDL") (collectively, the "License").  You
+ *    may not use this file except in compliance with the License.  You can
+ *    obtain a copy of the License at
+ *    https://github.com/payara/Payara/blob/master/LICENSE.txt
+ *    See the License for the specific
+ *    language governing permissions and limitations under the License.
+ *
+ *    When distributing the software, include this License Header Notice in each
+ *    file and include the License file at glassfish/legal/LICENSE.txt.
+ *
+ *    GPL Classpath Exception:
+ *    The Payara Foundation designates this particular file as subject to the "Classpath"
+ *    exception as provided by the Payara Foundation in the GPL Version 2 section of the License
+ *    file that accompanied this code.
+ *
+ *    Modifications:
+ *    If applicable, add the following below the License Header, with the fields
+ *    enclosed by brackets [] replaced by your own identifying information:
+ *    "Portions Copyright [year] [name of copyright owner]"
+ *
+ *    Contributor(s):
+ *    If you wish your version of this file to be governed by only the CDDL or
+ *    only the GPL Version 2, indicate your decision by adding "[Contributor]
+ *    elects to include this software in this distribution under the [CDDL or GPL
+ *    Version 2] license."  If you don't indicate a single choice of license, a
+ *    recipient has the option to distribute your version of this file under
+ *    either the CDDL, the GPL Version 2 or to extend the choice of license to
+ *    its licensees as provided above.  However, if you add GPL Version 2 code
+ *    and therefore, elected the GPL Version 2 license, then the option applies
+ *    only if the new code is made subject to such option by the copyright
+ *    holder.
+ */
+
+package org.glassfish.jersey.restclient;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.HeaderParam;
+import javax.ws.rs.Path;
+
+@Path("async")
+public class AsyncResourceImpl {
+
+    @GET
+    public String asyncCall(@HeaderParam("trace") String trace) {
+        return trace;
+    }
+}