diff --git a/cumulus/pallets/parachain-system/src/lib.rs b/cumulus/pallets/parachain-system/src/lib.rs
index 65a6baa2d79e4734bb1577898700af71cd0f576f..7fec98c2656fb563095b3f5b586aadcd05761779 100644
--- a/cumulus/pallets/parachain-system/src/lib.rs
+++ b/cumulus/pallets/parachain-system/src/lib.rs
@@ -32,7 +32,7 @@ use sp_runtime::traits::{BlakeTwo256, Hash};
use sp_inherents::{InherentData, InherentIdentifier, ProvideInherent};
use frame_support::{
decl_error, decl_event, decl_module, decl_storage,
- dispatch::{DispatchResult, DispatchError, DispatchResultWithPostInfo},
+ dispatch::{DispatchResult, DispatchResultWithPostInfo},
ensure, storage,
traits::Get,
weights::{DispatchClass, Weight, PostDispatchInfo, Pays},
@@ -212,15 +212,16 @@ decl_module! {
}
let (host_config, relevant_messaging_state) =
- relay_state_snapshot::extract_from_proof(
+ match relay_state_snapshot::extract_from_proof(
T::SelfParaId::get(),
vfp.relay_parent_storage_root,
relay_chain_state
- )
- .map_err(|err| {
- log::debug!("invalid relay chain merkle proof: {:?}", err);
- Error::<T>::InvalidRelayChainMerkleProof
- })?;
+ ) {
+ Ok(r) => r,
+ Err(err) => {
+ panic!("invalid relay chain merkle proof: {:?}", err);
+ }
+ };
ValidationData::put(&vfp);
RelevantMessagingState::put(relevant_messaging_state.clone());
@@ -233,11 +234,11 @@ decl_module! {
total_weight += Self::process_inbound_downward_messages(
relevant_messaging_state.dmq_mqc_head,
downward_messages,
- )?;
+ );
total_weight += Self::process_inbound_horizontal_messages(
&relevant_messaging_state.ingress_channels,
horizontal_messages,
- )?;
+ );
Ok(PostDispatchInfo { actual_weight: Some(total_weight), pays_fee: Pays::No })
}
@@ -480,10 +481,13 @@ impl<T: Config> Module<T> {
///
/// Checks if the sequence of the messages is valid, dispatches them and communicates the number
/// of processed messages to the collator via a storage update.
+ ///
+ /// **Panics** if it turns out that after processing all messages the Message Queue Chain hash
+ /// doesn't match the expected.
fn process_inbound_downward_messages(
expected_dmq_mqc_head: relay_chain::Hash,
downward_messages: Vec<InboundDownwardMessage>,
- ) -> Result<Weight, DispatchError> {
+ ) -> Weight {
let dm_count = downward_messages.len() as u32;
let mut weight_used = 0;
@@ -513,6 +517,9 @@ impl<T: Config> Module<T> {
// After hashing each message in the message queue chain submitted by the collator, we should
// arrive to the MQC head provided by the relay chain.
+ //
+ // A mismatch means that at least some of the submitted messages were altered, omitted or added
+ // improperly.
assert_eq!(result_mqc_head, expected_dmq_mqc_head);
} else {
assert_eq!(LastDmqMqcHead::get().0, expected_dmq_mqc_head);
@@ -522,25 +529,32 @@ impl<T: Config> Module<T> {
// PVF's `validate_block` wrapper and collation pipeline.
storage::unhashed::put(well_known_keys::PROCESSED_DOWNWARD_MESSAGES, &dm_count);
- Ok(weight_used)
+ weight_used
}
/// Process all inbound horizontal messages relayed by the collator.
///
/// This is similar to [`process_inbound_downward_messages`], but works on multiple inbound
/// channels.
+ ///
+ /// **Panics** if either any of horizontal messages submitted by the collator was sent from a
+ /// para which has no open channel to this parachain or if after processing messages
+ /// across all inbound channels MQCs were obtained which do not correspond to the
+ /// ones found on the relay-chain.
fn process_inbound_horizontal_messages(
ingress_channels: &[(ParaId, cumulus_primitives_core::AbridgedHrmpChannel)],
horizontal_messages: BTreeMap<ParaId, Vec<InboundHrmpMessage>>,
- ) -> Result<Weight, DispatchError> {
+ ) -> Weight {
// First, check that all submitted messages are sent from channels that exist. The channel
// exists if its MQC head is present in `vfp.hrmp_mqc_heads`.
for sender in horizontal_messages.keys() {
- ensure!(
+ // A violation of the assertion below indicates that one of the messages submitted by
+ // the collator was sent from a sender that doesn't have a channel opened to this parachain,
+ // according to the relay-parent state.
+ assert!(
ingress_channels
.binary_search_by_key(sender, |&(s, _)| s)
.is_ok(),
- Error::<T>::HrmpNoMqc,
);
}
@@ -605,8 +619,7 @@ impl<T: Config> Module<T> {
.or_insert_with(|| last_mqc_heads.get(&sender).cloned().unwrap_or_default())
.head();
let target_head = channel.mqc_head.unwrap_or_default();
-
- ensure!(cur_head == target_head, Error::<T>::HrmpMqcMismatch);
+ assert!(cur_head == target_head);
}
LastHrmpMqcHeads::put(running_mqc_heads);
@@ -616,7 +629,7 @@ impl<T: Config> Module<T> {
storage::unhashed::put(well_known_keys::HRMP_WATERMARK, &hrmp_watermark);
}
- Ok(weight_used)
+ weight_used
}
/// Put a new validation function into a particular location where polkadot
@@ -831,23 +844,6 @@ decl_error! {
ValidationDataNotAvailable,
/// The inherent which supplies the host configuration did not run this block
HostConfigurationNotAvailable,
- /// Invalid relay-chain storage merkle proof
- InvalidRelayChainMerkleProof,
- /// The messages submitted by the collator in the system inherent when hashed sequentially
- /// do not produce the hash that is produced by the relay-chain.
- ///
- /// This means that at least some of the submitted messages were altered, omitted or added
- /// illegaly.
- DmpMqcMismatch,
- /// The collator submitted a message that is received from a sender that doesn't have a
- /// channel opened to this parachain, according to the relay-parent state.
- HrmpNoMqc,
- /// After processing all messages submitted by the collator and extending hash chains we
- /// haven't arrived to the MQCs that were produced by the relay-chain.
- ///
- /// That means that one or more channels had at least some of the submitted messages altered,
- /// omitted or added illegaly.
- HrmpMqcMismatch,
/// No validation function upgrade is currently scheduled.
NotScheduled,
/// No code upgrade has been authorized.