solution: propagate native call exception to downstream

src/main/kotlin/io/emeraldpay/dshackle/rpc/NativeCall.kt

@@ -75,6 +75,7 @@ class NativeCall(
         }
         return BlockchainOuterClass.NativeCallReplyItem.newBuilder()
                 .setSucceed(false)
+                .setErrorMessage(it?.message ?: "Internal error")
                 .setId(id)
                 .build()
                 .toMono()
@@ -139,7 +140,7 @@ class NativeCall(
                     else CallFailure(ctx.id, it)
                 }
                 .switchIfEmpty(
-                        Mono.error<CallContext<ByteArray>>(CallFailure(ctx.id, Exception("No response or no available upstream for ${ctx.payload.method}")))
+                        Mono.error(CallFailure(ctx.id, Exception("No response or no available upstream for ${ctx.payload.method}")) as Throwable)
                 )
     }
 

src/main/kotlin/io/emeraldpay/dshackle/upstream/EthereumGrpcTransport.kt

@@ -24,6 +24,7 @@ import io.emeraldpay.grpc.Chain
 import io.infinitape.etherjar.rpc.Batch
 import io.infinitape.etherjar.rpc.JacksonRpcConverter
 import io.infinitape.etherjar.rpc.RpcException
+import io.infinitape.etherjar.rpc.RpcResponseError
 import io.infinitape.etherjar.rpc.transport.BatchStatus
 import io.infinitape.etherjar.rpc.transport.RpcTransport
 import reactor.core.publisher.Flux
@@ -74,7 +75,7 @@ class EthereumGrpcTransport(
                         bi.onError(e)
                     }
                 } else {
-                    bi.onError(RpcException(-32603, resp.error.toString()))
+                    bi.onError(RpcException(RpcResponseError.CODE_INTERNAL_ERROR, resp.errorMessage))
                 }
             }
             false

src/test/groovy/io/emeraldpay/dshackle/rpc/NativeCallSpec.groovy

@@ -135,6 +135,7 @@ class NativeCallSpec extends Specification {
         StepVerifier.create(resp)
                 .expectNext(BlockchainOuterClass.NativeCallReplyItem.newBuilder()
                         .setSucceed(false)
+                        .setErrorMessage("Failed to call 5: test test")
                         .setId(5)
                         .build())
                 .expectComplete()
@@ -151,6 +152,7 @@ class NativeCallSpec extends Specification {
         StepVerifier.create(resp)
                 .expectNext(BlockchainOuterClass.NativeCallReplyItem.newBuilder()
                         .setSucceed(false)
+                        .setErrorMessage("test test")
                         .build())
                 .expectComplete()
                 .verify(Duration.ofSeconds(1))