Propagate error instance ID from remote errors

changelog/@unreleased/pr-235.v2.yml

@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: The error instance ID of remote errors is now propagated.
+  links:
+  - https://github.com/palantir/conjure-rust-runtime/pull/235

conjure-runtime/src/service/http_error.rs

@@ -16,7 +16,7 @@ use crate::raw::Service;
 use crate::service::Layer;
 use crate::{builder, Builder, ServerQos, ServiceError};
 use bytes::{BufMut, BytesMut};
-use conjure_error::Error;
+use conjure_error::{Error, ErrorType, Internal};
 use conjure_serde::json;
 use futures::StreamExt;
 use http::header::RETRY_AFTER;
@@ -149,9 +149,11 @@ where
                         let e = e.clone();
                         Error::propagated_service_safe(error, e)
                     }
-                    (Some(_), ServiceError::WrapInNewError) | (None, _) => {
-                        Error::internal_safe(error)
+                    (Some(e), ServiceError::WrapInNewError) => {
+                        let instance_id = e.error_instance_id();
+                        Error::service_safe(error, Internal::new().with_instance_id(instance_id))
                     }
+                    (None, _) => Error::internal_safe(error),
                 };
 
                 if log_body {
@@ -300,7 +302,7 @@ mod test {
             _ => panic!("expected a service error"),
         };
         assert_eq!(*service.error_code(), ErrorCode::Internal);
-        assert_ne!(
+        assert_eq!(
             service.error_instance_id(),
             service_error.error_instance_id()
         );