Deterministic host timestamp

.changelog/unreleased/bug-fixes/ibc/1770-deterministic-host-timestamp.md

@@ -0,0 +1,2 @@
+- IBC handlers now retrieve the host timestamp from the latest host consensus
+  state ([#1770](https://github.com/informalsystems/ibc-rs/issues/1770))

modules/src/clients/ics07_tendermint/client_def.rs

@@ -2,7 +2,6 @@ use core::convert::TryInto;
 
 use ibc_proto::ibc::core::commitment::v1::MerkleProof as RawMerkleProof;
 use prost::Message;
-use tendermint::Time;
 use tendermint_light_client_verifier::types::{TrustedBlockState, UntrustedBlockState};
 use tendermint_light_client_verifier::{ProdVerifier, Verdict, Verifier};
 use tendermint_proto::Protobuf;
@@ -50,7 +49,6 @@ impl ClientDef for TendermintClient {
 
     fn check_header_and_update_state(
         &self,
-        now: Time,
         ctx: &dyn ClientReader,
         client_id: ClientId,
         client_state: Self::ClientState,
@@ -113,9 +111,12 @@ impl ClientDef for TendermintClient {
 
         let options = client_state.as_light_client_options()?;
 
-        let verdict = self
-            .verifier
-            .verify(untrusted_state, trusted_state, &options, now);
+        let verdict = self.verifier.verify(
+            untrusted_state,
+            trusted_state,
+            &options,
+            ctx.host_timestamp().into_tm_time().unwrap(),
+        );
 
         match verdict {
             Verdict::Success => {}

modules/src/core/ics02_client/client_def.rs

@@ -1,5 +1,4 @@
 use ibc_proto::ibc::core::commitment::v1::MerkleProof;
-use tendermint::Time;
 
 use crate::clients::ics07_tendermint::client_def::TendermintClient;
 use crate::core::ics02_client::client_consensus::{AnyConsensusState, ConsensusState};
@@ -30,7 +29,6 @@ pub trait ClientDef: Clone {
 
     fn check_header_and_update_state(
         &self,
-        now: Time,
         ctx: &dyn ClientReader,
         client_id: ClientId,
         client_state: Self::ClientState,
@@ -197,7 +195,6 @@ impl ClientDef for AnyClient {
     /// Validates an incoming `header` against the latest consensus state of this client.
     fn check_header_and_update_state(
         &self,
-        now: Time,
         ctx: &dyn ClientReader,
         client_id: ClientId,
         client_state: AnyClientState,
@@ -211,13 +208,8 @@ 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(
-                    now,
-                    ctx,
-                    client_id,
-                    client_state,
-                    header,
-                )?;
+                let (new_state, new_consensus) =
+                    client.check_header_and_update_state(ctx, client_id, client_state, header)?;
 
                 Ok((
                     AnyClientState::Tendermint(new_state),
@@ -233,13 +225,8 @@ 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(
-                    now,
-                    ctx,
-                    client_id,
-                    client_state,
-                    header,
-                )?;
+                let (new_state, new_consensus) =
+                    client.check_header_and_update_state(ctx, client_id, client_state, header)?;
 
                 Ok((
                     AnyClientState::Mock(new_state),

modules/src/core/ics02_client/context.rs

@@ -8,6 +8,7 @@ use crate::core::ics02_client::client_type::ClientType;
 use crate::core::ics02_client::error::{Error, ErrorDetail};
 use crate::core::ics02_client::handler::ClientResult::{self, Create, Update, Upgrade};
 use crate::core::ics24_host::identifier::ClientId;
+use crate::timestamp::Timestamp;
 use crate::Height;
 
 /// Defines the read-only part of ICS2 (client functions) context.
@@ -58,6 +59,20 @@ pub trait ClientReader {
     /// Returns the current height of the local chain.
     fn host_height(&self) -> Height;
 
+    /// Returns the current timestamp of the local chain.
+    fn host_timestamp(&self) -> Timestamp {
+        let pending_consensus_state = self
+            .pending_host_consensus_state()
+            .expect("host must have pending consensus state");
+        pending_consensus_state.timestamp()
+    }
+
+    /// Returns the `ConsensusState` of the host (local) chain at a specific height.
+    fn host_consensus_state(&self, height: Height) -> Result<AnyConsensusState, Error>;
+
+    /// Returns the pending `ConsensusState` of the host (local) chain.
+    fn pending_host_consensus_state(&self) -> Result<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>;
@@ -78,8 +93,16 @@ pub trait ClientKeeper {
                     res.consensus_state,
                 )?;
                 self.increase_client_counter();
-                self.store_update_time(res.client_id.clone(), res.client_state.latest_height())?;
-                self.store_update_height(res.client_id, res.client_state.latest_height())?;
+                self.store_update_time(
+                    res.client_id.clone(),
+                    res.client_state.latest_height(),
+                    res.processed_time,
+                )?;
+                self.store_update_height(
+                    res.client_id,
+                    res.client_state.latest_height(),
+                    res.processed_height,
+                )?;
                 Ok(())
             }
             Update(res) => {
@@ -89,8 +112,16 @@ pub trait ClientKeeper {
                     res.client_state.latest_height(),
                     res.consensus_state,
                 )?;
-                self.store_update_time(res.client_id.clone(), res.client_state.latest_height())?;
-                self.store_update_height(res.client_id, res.client_state.latest_height())?;
+                self.store_update_time(
+                    res.client_id.clone(),
+                    res.client_state.latest_height(),
+                    res.processed_time,
+                )?;
+                self.store_update_height(
+                    res.client_id,
+                    res.client_state.latest_height(),
+                    res.processed_height,
+                )?;
                 Ok(())
             }
             Upgrade(res) => {
@@ -133,12 +164,22 @@ pub trait ClientKeeper {
     fn increase_client_counter(&mut self);
 
     /// Called upon successful client update.
-    /// Implementations are expected to use this to record the current (host) time as the time at
-    /// which this update (or header) was processed.
-    fn store_update_time(&mut self, client_id: ClientId, height: Height) -> Result<(), Error>;
+    /// Implementations are expected to use this to record the specified time as the time at which
+    /// this update (or header) was processed.
+    fn store_update_time(
+        &mut self,
+        client_id: ClientId,
+        height: Height,
+        timestamp: Timestamp,
+    ) -> Result<(), Error>;
 
     /// Called upon successful client update.
-    /// Implementations are expected to use this to record the current (host) height as the height
+    /// Implementations are expected to use this to record the specified height as the height at
     /// at which this update (or header) was processed.
-    fn store_update_height(&mut self, client_id: ClientId, height: Height) -> Result<(), Error>;
+    fn store_update_height(
+        &mut self,
+        client_id: ClientId,
+        height: Height,
+        host_height: Height,
+    ) -> Result<(), Error>;
 }

modules/src/core/ics02_client/error.rs

@@ -249,6 +249,10 @@ define_error! {
             [ Ics07Error ]
             | _ | { format_args!("Tendermint-specific handler error") },
 
+        MissingLocalConsensusState
+            { height: Height }
+            | e | { format_args!("the local consensus state could not be retrieved for height {}", e.height) },
+
     }
 }
 

modules/src/core/ics02_client/handler.rs

@@ -1,7 +1,5 @@
 //! This module implements the processing logic for ICS2 (client abstractions and functions) msgs.
 
-use tendermint::Time;
-
 use crate::core::ics02_client::context::ClientReader;
 use crate::core::ics02_client::error::Error;
 use crate::core::ics02_client::msgs::ClientMsg;
@@ -19,17 +17,13 @@ pub enum ClientResult {
 }
 
 /// General entry point for processing any message related to ICS2 (client functions) protocols.
-pub fn dispatch<Ctx>(
-    now: Time,
-    ctx: &Ctx,
-    msg: ClientMsg,
-) -> Result<HandlerOutput<ClientResult>, Error>
+pub fn dispatch<Ctx>(ctx: &Ctx, msg: ClientMsg) -> Result<HandlerOutput<ClientResult>, Error>
 where
     Ctx: ClientReader,
 {
     match msg {
-        ClientMsg::CreateClient(msg) => create_client::process(now, ctx, msg),
-        ClientMsg::UpdateClient(msg) => update_client::process(now, ctx, msg),
+        ClientMsg::CreateClient(msg) => create_client::process(ctx, msg),
+        ClientMsg::UpdateClient(msg) => update_client::process(ctx, msg),
         ClientMsg::UpgradeClient(msg) => upgrade_client::process(ctx, msg),
         _ => {
             unimplemented!()

modules/src/core/ics02_client/handler/create_client.rs

@@ -1,7 +1,5 @@
 //! Protocol logic specific to processing ICS2 messages of type `MsgCreateAnyClient`.
 
-use tendermint::Time;
-
 use crate::prelude::*;
 
 use crate::core::ics02_client::client_consensus::AnyConsensusState;
@@ -17,6 +15,7 @@ use crate::core::ics24_host::identifier::ClientId;
 use crate::events::IbcEvent;
 use crate::handler::{HandlerOutput, HandlerResult};
 use crate::timestamp::Timestamp;
+
 /// The result following the successful processing of a `MsgCreateAnyClient` message. Preferably
 /// this data type should be used with a qualified name `create_client::Result` to avoid ambiguity.
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -30,7 +29,6 @@ pub struct Result {
 }
 
 pub fn process(
-    now: Time,
     ctx: &dyn ClientReader,
     msg: MsgCreateAnyClient,
 ) -> HandlerResult<ClientResult, Error> {
@@ -52,7 +50,7 @@ pub fn process(
         client_type: msg.client_state().client_type(),
         client_state: msg.client_state(),
         consensus_state: msg.consensus_state(),
-        processed_time: now.into(),
+        processed_time: ctx.host_timestamp(),
         processed_height: ctx.host_height(),
     });
 
@@ -70,7 +68,6 @@ mod tests {
     use crate::prelude::*;
 
     use core::time::Duration;
-    use tendermint::Time;
     use test_log::test;
 
     use crate::clients::ics07_tendermint::client_state::{
@@ -107,7 +104,7 @@ mod tests {
         )
         .unwrap();
 
-        let output = dispatch(Time::now(), &ctx, ClientMsg::CreateClient(msg.clone()));
+        let output = dispatch(&ctx, ClientMsg::CreateClient(msg.clone()));
 
         match output {
             Ok(HandlerOutput {
@@ -198,7 +195,7 @@ mod tests {
         let expected_client_id = ClientId::new(ClientType::Mock, 0).unwrap();
 
         for msg in create_client_msgs {
-            let output = dispatch(Time::now(), &ctx, ClientMsg::CreateClient(msg.clone()));
+            let output = dispatch(&ctx, ClientMsg::CreateClient(msg.clone()));
 
             match output {
                 Ok(HandlerOutput {
@@ -260,7 +257,7 @@ mod tests {
         )
         .unwrap();
 
-        let output = dispatch(Time::now(), &ctx, ClientMsg::CreateClient(msg.clone()));
+        let output = dispatch(&ctx, ClientMsg::CreateClient(msg.clone()));
 
         match output {
             Ok(HandlerOutput {