Few improvements to errors from sdk-shared-core: (#513)

* Improve the non-deterministic error, adding some nice to read diff
* Correctly report command index/command name only when known.

Author: slinkydeveloper

.gitignore

@@ -36,3 +36,5 @@ build
 .factorypath
 kls_database.db
 .kotlin
+
+.restate

examples/src/main/java/my/restate/sdk/examples/Greeter.java

@@ -0,0 +1,36 @@
+// Copyright (c) 2023 - Restate Software, Inc., Restate GmbH
+//
+// This file is part of the Restate Java SDK,
+// which is released under the MIT license.
+//
+// You can find a copy of the license in file LICENSE in the root
+// directory of this repository or package, or at
+// https://github.com/restatedev/sdk-java/blob/main/LICENSE
+package my.restate.sdk.examples;
+
+import dev.restate.sdk.Context;
+import dev.restate.sdk.annotation.Handler;
+import dev.restate.sdk.annotation.Service;
+import dev.restate.sdk.endpoint.Endpoint;
+import dev.restate.sdk.http.vertx.RestateHttpServer;
+import java.time.Duration;
+
+@Service
+public class Greeter {
+
+  public record Greeting(String name) {}
+
+  public record GreetingResponse(String message) {}
+
+  @Handler
+  public GreetingResponse greet(Context ctx, Greeting req) {
+    // Respond to caller
+    return new GreetingResponse("You said hi to " + req.name + "!");
+  }
+
+  public static void main(String[] args) {
+    RestateHttpServer.listen(
+        Endpoint.bind(
+            new Greeter(), configurator -> configurator.inactivityTimeout(Duration.ofSeconds(1))));
+  }
+}

sdk-core/src/main/java/dev/restate/sdk/core/ProtocolException.java

@@ -18,11 +18,12 @@ public class ProtocolException extends RuntimeException {
   static final int NOT_FOUND_CODE = 404;
   public static final int UNSUPPORTED_MEDIA_TYPE_CODE = 415;
   public static final int INTERNAL_CODE = 500;
-  static final int JOURNAL_MISMATCH_CODE = 570;
+  public static final int JOURNAL_MISMATCH_CODE = 570;
   static final int PROTOCOL_VIOLATION_CODE = 571;
+  static final int CLOSED_CODE = 598;
 
   @SuppressWarnings("StaticAssignmentOfThrowable")
-  static final ProtocolException CLOSED = new ProtocolException("Invocation closed");
+  static final ProtocolException CLOSED = new ProtocolException("Invocation closed", CLOSED_CODE);
 
   private final int code;
 
@@ -54,10 +55,10 @@ public static ProtocolException unexpectedMessage(
         PROTOCOL_VIOLATION_CODE);
   }
 
-  public static ProtocolException unexpectedMessage(String type, MessageLite actual) {
+  public static ProtocolException unexpectedMessage(String expected, MessageLite actual) {
     return new ProtocolException(
         "Unexpected message type received from the runtime. Expected: '"
-            + type
+            + expected
             + "', Actual: '"
             + actual.getClass().getCanonicalName()
             + "'",
@@ -69,25 +70,6 @@ static ProtocolException unexpectedNotificationVariant(Class<?> clazz) {
         "Unexpected notification variant " + clazz.getName(), PROTOCOL_VIOLATION_CODE);
   }
 
-  public static ProtocolException commandDoesNotMatch(MessageLite expected, MessageLite actual) {
-    return new ProtocolException(
-        "Replayed journal doesn't match the handler code.\nThe handler code generated: "
-            + expected
-            + "\nwhile the replayed entry is: "
-            + actual,
-        JOURNAL_MISMATCH_CODE);
-  }
-
-  public static ProtocolException commandClassDoesNotMatch(
-      Class<? extends MessageLite> expectedClazz, MessageLite actual) {
-    return new ProtocolException(
-        "Replayed journal doesn't match the handler code.\nThe handler code generated: "
-            + expectedClazz.getName()
-            + "\nwhile the replayed entry is: "
-            + actual,
-        JOURNAL_MISMATCH_CODE);
-  }
-
   public static ProtocolException commandsToProcessIsEmpty() {
     return new ProtocolException("Expecting command queue to be non empty", JOURNAL_MISMATCH_CODE);
   }

sdk-core/src/main/java/dev/restate/sdk/core/statemachine/ClosedState.java

@@ -15,7 +15,10 @@ final class ClosedState implements State {
 
   @Override
   public void hitError(
-      Throwable throwable, @Nullable Duration nextRetryDelay, StateContext stateContext) {
+      Throwable throwable,
+      @Nullable CommandRelationship relatedCommand,
+      @Nullable Duration nextRetryDelay,
+      StateContext stateContext) {
     // Ignore, as we closed already
   }