ICS07: Add verification method for client update handler

.changelog/unreleased/breaking-changes/ibc/1214-ics07.md

@@ -0,0 +1,3 @@
+- The `check_header_and_update_state` method of the `ClientDef`
+  trait (ICS02) has been expanded to facilitate ICS07
+  ([#1214](https://github.com/informalsystems/ibc-rs/issues/1214))

.changelog/unreleased/features/ibc/1214-ics07.md

@@ -0,0 +1,2 @@
+- Add ICS07 verification functionality by using `tendermint-light-client`
+  ([#1214](https://github.com/informalsystems/ibc-rs/issues/1214))

modules/Cargo.toml

@@ -45,6 +45,9 @@ version = "=0.22.0"
 [dependencies.tendermint-proto]
 version = "=0.22.0"
 
+[dependencies.tendermint-light-client]
+version = "=0.22.0"
+
 [dependencies.tendermint-testgen]
 version = "=0.22.0"
 optional = true

modules/src/application/ics20_fungible_token_transfer/msgs/transfer.rs

@@ -101,14 +101,17 @@ impl From<MsgTransfer> for RawMsgTransfer {
 
 #[cfg(test)]
 pub mod test_util {
+    use std::ops::Add;
+    use std::time::Duration;
+
     use crate::{
         ics24_host::identifier::{ChannelId, PortId},
         test_utils::get_dummy_account_id,
+        timestamp::Timestamp,
         Height,
     };
 
     use super::MsgTransfer;
-    use crate::timestamp::Timestamp;
 
     // Returns a dummy `RawMsgTransfer`, for testing only!
     pub fn get_dummy_msg_transfer(height: u64) -> MsgTransfer {
@@ -120,7 +123,7 @@ pub mod test_util {
             token: None,
             sender: id.clone(),
             receiver: id,
-            timeout_timestamp: Timestamp::from_nanoseconds(1).unwrap(),
+            timeout_timestamp: Timestamp::now().add(Duration::from_secs(10)).unwrap(),
             timeout_height: Height {
                 revision_number: 0,
                 revision_height: height,

modules/src/ics02_client/client_def.rs

@@ -4,6 +4,7 @@ use crate::downcast;
 use crate::ics02_client::client_consensus::{AnyConsensusState, ConsensusState};
 use crate::ics02_client::client_state::{AnyClientState, ClientState};
 use crate::ics02_client::client_type::ClientType;
+use crate::ics02_client::context::ClientReader;
 use crate::ics02_client::error::Error;
 use crate::ics02_client::header::{AnyHeader, Header};
 use crate::ics03_connection::connection::ConnectionEnd;
@@ -23,13 +24,15 @@ pub trait ClientDef: Clone {
     type ClientState: ClientState;
     type ConsensusState: ConsensusState;
 
-    /// TODO
     fn check_header_and_update_state(
         &self,
+        ctx: &dyn ClientReader,
+        client_id: ClientId,
         client_state: Self::ClientState,
         header: Self::Header,
     ) -> Result<(Self::ClientState, Self::ConsensusState), Error>;
 
+    /// TODO
     fn verify_upgrade_and_update_state(
         &self,
         client_state: &Self::ClientState,
@@ -156,7 +159,7 @@ pub enum AnyClient {
 impl AnyClient {
     pub fn from_client_type(client_type: ClientType) -> AnyClient {
         match client_type {
-            ClientType::Tendermint => Self::Tendermint(TendermintClient),
+            ClientType::Tendermint => Self::Tendermint(TendermintClient::default()),
 
             #[cfg(any(test, feature = "mocks"))]
             ClientType::Mock => Self::Mock(MockClient),
@@ -173,6 +176,8 @@ impl ClientDef for AnyClient {
     /// Validates an incoming `header` against the latest consensus state of this client.
     fn check_header_and_update_state(
         &self,
+        ctx: &dyn ClientReader,
+        client_id: ClientId,
         client_state: AnyClientState,
         header: AnyHeader,
     ) -> Result<(AnyClientState, AnyConsensusState), Error> {
@@ -185,7 +190,7 @@ impl ClientDef for AnyClient {
                 .ok_or_else(|| Error::client_args_type_mismatch(ClientType::Tendermint))?;
 
                 let (new_state, new_consensus) =
-                    client.check_header_and_update_state(client_state, header)?;
+                    client.check_header_and_update_state(ctx, client_id, client_state, header)?;
 
                 Ok((
                     AnyClientState::Tendermint(new_state),
@@ -202,7 +207,7 @@ impl ClientDef for AnyClient {
                 .ok_or_else(|| Error::client_args_type_mismatch(ClientType::Mock))?;
 
                 let (new_state, new_consensus) =
-                    client.check_header_and_update_state(client_state, header)?;
+                    client.check_header_and_update_state(ctx, client_id, client_state, header)?;
 
                 Ok((
                     AnyClientState::Mock(new_state),

modules/src/ics02_client/context.rs

@@ -5,7 +5,7 @@
 use crate::ics02_client::client_consensus::AnyConsensusState;
 use crate::ics02_client::client_state::AnyClientState;
 use crate::ics02_client::client_type::ClientType;
-use crate::ics02_client::error::Error;
+use crate::ics02_client::error::{Error, ErrorDetail};
 use crate::ics02_client::handler::ClientResult::{self, Create, Update, Upgrade};
 use crate::ics24_host::identifier::ClientId;
 use crate::Height;
@@ -14,12 +14,47 @@ use crate::Height;
 pub trait ClientReader {
     fn client_type(&self, client_id: &ClientId) -> Result<ClientType, Error>;
     fn client_state(&self, client_id: &ClientId) -> Result<AnyClientState, Error>;
+
+    /// Retrieve the consensus state for the given client ID at the specified
+    /// height.
+    ///
+    /// Returns an error if no such state exists.
     fn consensus_state(
         &self,
         client_id: &ClientId,
         height: Height,
     ) -> Result<AnyConsensusState, Error>;
 
+    /// Similar to `consensus_state`, attempt to retrieve the consensus state,
+    /// but return `None` if no state exists at the given height.
+    fn maybe_consensus_state(
+        &self,
+        client_id: &ClientId,
+        height: Height,
+    ) -> Result<Option<AnyConsensusState>, Error> {
+        match self.consensus_state(client_id, height) {
+            Ok(cs) => Ok(Some(cs)),
+            Err(e) => match e.detail() {
+                ErrorDetail::ConsensusStateNotFound(_) => Ok(None),
+                _ => Err(e),
+            },
+        }
+    }
+
+    /// Search for the lowest consensus state higher than `height`.
+    fn next_consensus_state(
+        &self,
+        client_id: &ClientId,
+        height: Height,
+    ) -> Result<Option<AnyConsensusState>, Error>;
+
+    /// Search for the highest consensus state lower than `height`.
+    fn prev_consensus_state(
+        &self,
+        client_id: &ClientId,
+        height: Height,
+    ) -> Result<Option<AnyConsensusState>, Error>;
+
     /// Returns a natural number, counting how many clients have been created thus far.
     /// The value of this counter should increase only via method `ClientKeeper::increase_client_counter`.
     fn client_counter(&self) -> Result<u64, Error>;

modules/src/ics02_client/error.rs

@@ -9,8 +9,12 @@ use crate::ics07_tendermint::error::Error as Ics07Error;
 use crate::ics23_commitment::error::Error as Ics23Error;
 use crate::ics24_host::error::ValidationError;
 use crate::ics24_host::identifier::ClientId;
+use crate::timestamp::Timestamp;
 use crate::Height;
 
+use tendermint::Error as TendermintError;
+use tendermint_proto::Error as TendermintProtoError;
+
 define_error! {
     #[derive(Debug, PartialEq, Eq)]
     Error {
@@ -58,7 +62,7 @@ define_error! {
 
         FailedTrustThresholdConversion
             { numerator: u64, denominator: u64 }
-            [ tendermint::Error ]
+            [ TendermintError ]
             | e | { format_args!("failed to build Tendermint domain type trust threshold from fraction: {}/{}", e.numerator, e.denominator) },
 
         UnknownClientStateType
@@ -105,14 +109,14 @@ define_error! {
             },
 
         DecodeRawClientState
-            [ TraceError<tendermint_proto::Error> ]
+            [ TraceError<TendermintProtoError> ]
             | _ | { "error decoding raw client state" },
 
         MissingRawClientState
             | _ | { "missing raw client state" },
 
         InvalidRawConsensusState
-            [ TraceError<tendermint_proto::Error> ]
+            [ TraceError<TendermintProtoError> ]
             | _ | { "invalid raw client consensus state" },
 
         MissingRawConsensusState
@@ -134,14 +138,14 @@ define_error! {
             | _ | { "invalid client identifier" },
 
         InvalidRawHeader
-            [ TraceError<tendermint_proto::Error> ]
+            [ TraceError<TendermintProtoError> ]
             | _ | { "invalid raw header" },
 
         MissingRawHeader
             | _ | { "missing raw header" },
 
         DecodeRawMisbehaviour
-            [ TraceError<tendermint_proto::Error> ]
+            [ TraceError<TendermintProtoError> ]
             | _ | { "invalid raw misbehaviour" },
 
         InvalidRawMisbehaviour
@@ -180,6 +184,12 @@ define_error! {
                     e.client_type)
             },
 
+        InsufficientVotingPower
+            { reason: String }
+            | e | {
+                format_args!("Insufficient overlap {}", e.reason)
+            },
+
         RawClientAndConsensusStateTypesMismatch
             {
                 state_type: ClientType,
@@ -206,8 +216,37 @@ define_error! {
                 client_height: Height,
             }
             | e | {
-                format_args!("upgraded client height {0} must be at greater than current client height {1}",
+                format_args!("upgraded client height {} must be at greater than current client height {}",
                     e.upgraded_height, e.client_height)
             },
+
+        InvalidConsensusStateTimestamp
+            {
+                time1: Timestamp,
+                time2: Timestamp,
+            }
+            | e | {
+                format_args!("Timestamp none or {} and now {}", e.time1, e.time2)
+            },
+
+        HeaderNotWithinTrustPeriod
+            {
+                latest_time:Timestamp,
+                update_time: Timestamp,
+            }
+            | e | {
+                format_args!("Header not withing trusting period: expires_at={0} now={1}", e.latest_time, e.update_time)
+            },
+
+        TendermintHandlerError
+            [ Ics07Error ]
+            | _ | { format_args!("Tendermint-specific handler error") },
+
+    }
+}
+
+impl From<Ics07Error> for Error {
+    fn from(e: Ics07Error) -> Error {
+        Error::tendermint_handler_error(e)
     }
 }