Fix communication with runtime for build_header and misbehaviour (inf…

…ormalsystems#858)

* Send full misbehavior result through runtime channel

* Fix event decoding unwraps and some_attribute to return None when tag is missing

* Proper error handling from runtime when building header

modules/src/events.rs

@@ -254,6 +254,8 @@ macro_rules! attribute {
 #[macro_export]
 macro_rules! some_attribute {
     ($a:ident, $b:literal) => {
-        $a.events.get($b).ok_or($b)?[$a.idx].parse().ok()
+        $a.events
+            .get($b)
+            .map_or_else(|| None, |tags| tags[$a.idx].parse().ok())
     };
 }

modules/src/ics02_client/events.rs

@@ -6,12 +6,12 @@ use serde_derive::{Deserialize, Serialize};
 use subtle_encoding::hex;
 use tendermint_proto::Protobuf;
 
-use crate::attribute;
 use crate::events::{IbcEvent, RawObject};
 use crate::ics02_client::client_type::ClientType;
 use crate::ics02_client::header::AnyHeader;
 use crate::ics02_client::height::Height;
 use crate::ics24_host::identifier::ClientId;
+use crate::{attribute, some_attribute};
 
 /// The content of the `type` field for the event that a chain produces upon executing the create client transaction.
 const CREATE_EVENT_TYPE: &str = "create_client";
@@ -222,9 +222,14 @@ impl From<Attributes> for UpdateClient {
 impl TryFrom<RawObject> for UpdateClient {
     type Error = BoxError;
     fn try_from(obj: RawObject) -> Result<Self, Self::Error> {
-        let header_str: String = attribute!(obj, "update_client.header");
-        let header_bytes = hex::decode(header_str).unwrap();
-        let header: AnyHeader = Protobuf::decode(header_bytes.as_ref()).unwrap();
+        let header_str: Option<String> = some_attribute!(obj, "update_client.header");
+        let header: Option<AnyHeader> = match header_str {
+            Some(str) => {
+                let header_bytes = hex::decode(str)?;
+                Some(Protobuf::decode(header_bytes.as_ref())?)
+            }
+            None => None,
+        };
         let consensus_height_str: String = attribute!(obj, "update_client.consensus_height");
         Ok(UpdateClient {
             common: Attributes {
@@ -233,7 +238,7 @@ impl TryFrom<RawObject> for UpdateClient {
                 client_type: attribute!(obj, "update_client.client_type"),
                 consensus_height: consensus_height_str.as_str().try_into()?,
             },
-            header: Some(header),
+            header,
         })
     }
 }

relayer/src/chain/runtime.rs

@@ -370,25 +370,27 @@ impl<C: Chain + Send + 'static> ChainRuntime<C> {
         client_state: AnyClientState,
         reply_to: ReplyTo<AnyHeader>,
     ) -> Result<(), Error> {
-        let header = {
-            // Get the light block at trusted_height + 1 from chain.
-            //
-            // TODO: This is tendermint specific and needs to be refactored during
-            //       the relayer light client refactoring.
-            // NOTE: This is needed to get the next validator set. While there is a next validator set
-            //       in the light block at trusted height, the proposer is not known/set in this set.
-            let trusted_light_block = self.light_client.fetch(trusted_height.increment())?;
-
-            // Get the light block at target_height from chain.
-            let target_light_block =
-                self.light_client
-                    .verify(trusted_height, target_height, &client_state)?;
-
-            let header =
-                self.chain
-                    .build_header(trusted_height, trusted_light_block, target_light_block)?;
-
-            Ok(header.wrap_any())
+        // Get the light block at trusted_height + 1 from chain.
+        //
+        // TODO: This is tendermint specific and needs to be refactored during
+        //       the relayer light client refactoring.
+        // NOTE: This is needed to get the next validator set. While there is a next validator set
+        //       in the light block at trusted height, the proposer is not known/set in this set.
+        let trusted_light_block = self.light_client.fetch(trusted_height.increment());
+
+        // Get the light block at target_height from chain.
+        let target_light_block =
+            self.light_client
+                .verify(trusted_height, target_height, &client_state);
+
+        // Try to build the header, return first error encountered.
+        let header = match (trusted_light_block, target_light_block) {
+            (Err(eta), _) => Err(eta),
+            (_, Err(etr)) => Err(etr),
+            (Ok(trusted_light_block), Ok(target_light_block)) => self
+                .chain
+                .build_header(trusted_height, trusted_light_block, target_light_block)
+                .map_or_else(Err, |header| Ok(header.wrap_any())),
         };
 
         reply_to
@@ -447,10 +449,10 @@ impl<C: Chain + Send + 'static> ChainRuntime<C> {
     ) -> Result<(), Error> {
         let misbehaviour = self
             .light_client
-            .check_misbehaviour(update_event, &client_state)?;
+            .check_misbehaviour(update_event, &client_state);
 
         reply_to
-            .send(Ok(misbehaviour))
+            .send(misbehaviour)
             .map_err(|e| Kind::Channel.context(e))?;
 
         Ok(())

relayer/src/foreign_client.rs

@@ -40,7 +40,7 @@ pub enum ForeignClientError {
     #[error("failed while finding client {0}: expected chain_id in client state: {1}; actual chain_id: {2}")]
     ClientFind(ClientId, ChainId, ChainId),
 
-    #[error("error raised while submitting the misbehaviour evidence: {0}")]
+    #[error("error raised while checking for misbehaviour evidence: {0}")]
     Misbehaviour(String),
 
     #[error("failed while trying to upgrade client id {0} with error: {1}")]