Set default trusting period to be 2/3 of unbonding period for Cosmos chains

.changelog/unreleased/improvements/ibc-relayer/1392-trusting-period-default.md

@@ -0,0 +1,2 @@
+- Set default trusting period to be 2/3 of unbonding period for Cosmos chains
+  ([#1392](https://github.com/informalsystems/ibc-rs/issues/1392))

relayer/src/chain/cosmos.rs

@@ -599,6 +599,12 @@ impl CosmosSdkChain {
             Err(_) => Err(Error::tx_no_confirmation()),
         }
     }
+
+    fn trusting_period(&self, unbonding_period: Duration) -> Duration {
+        self.config
+            .trusting_period
+            .unwrap_or(2 * unbonding_period / 3)
+    }
 }
 
 fn empty_event_present(events: &[IbcEvent]) -> bool {
@@ -1635,12 +1641,13 @@ impl ChainEndpoint for CosmosSdkChain {
     }
 
     fn build_client_state(&self, height: ICSHeight) -> Result<Self::ClientState, Error> {
+        let unbonding_period = self.unbonding_period()?;
         // Build the client state.
         ClientState::new(
             self.id().clone(),
             self.config.trust_threshold.into(),
-            self.config.trusting_period,
-            self.unbonding_period()?,
+            self.trusting_period(unbonding_period),
+            unbonding_period,
             self.config.clock_drift,
             height,
             ICSHeight::zero(),

relayer/src/chain/mock.rs

@@ -61,6 +61,14 @@ pub struct MockChain {
     event_receiver: EventReceiver,
 }
 
+impl MockChain {
+    fn trusting_period(&self) -> Duration {
+        self.config
+            .trusting_period
+            .unwrap_or_else(|| Duration::from_secs(14 * 24 * 60 * 60)) // 14 days
+    }
+}
+
 impl ChainEndpoint for MockChain {
     type LightBlock = TmLightBlock;
     type Header = TendermintHeader;
@@ -317,8 +325,8 @@ impl ChainEndpoint for MockChain {
         let client_state = TendermintClientState::new(
             self.id().clone(),
             self.config.trust_threshold.into(),
-            self.config.trusting_period,
-            self.config.trusting_period.add(Duration::from_secs(1000)),
+            self.trusting_period(),
+            self.trusting_period().add(Duration::from_secs(1000)),
             Duration::from_millis(3000),
             height,
             Height::zero(),
@@ -426,7 +434,7 @@ pub mod test_utils {
             max_msg_num: Default::default(),
             max_tx_size: Default::default(),
             clock_drift: Duration::from_secs(5),
-            trusting_period: Duration::from_secs(14 * 24 * 60 * 60), // 14 days
+            trusting_period: Some(Duration::from_secs(14 * 24 * 60 * 60)), // 14 days
             trust_threshold: Default::default(),
             packet_filter: PacketFilter::default(),
             address_type: AddressType::default(),

relayer/src/config.rs

@@ -97,10 +97,6 @@ pub mod default {
         Duration::from_secs(10)
     }
 
-    pub fn trusting_period() -> Duration {
-        Duration::from_secs(336 * 60 * 60) // 336 hours ~ 14 days
-    }
-
     pub fn clock_drift() -> Duration {
         Duration::from_secs(5)
     }
@@ -322,8 +318,8 @@ pub struct ChainConfig {
     pub max_tx_size: MaxTxSize,
     #[serde(default = "default::clock_drift", with = "humantime_serde")]
     pub clock_drift: Duration,
-    #[serde(default = "default::trusting_period", with = "humantime_serde")]
-    pub trusting_period: Duration,
+    #[serde(with = "humantime_serde")]
+    pub trusting_period: Option<Duration>,
 
     // these two need to be last otherwise we run into `ValueAfterTable` error when serializing to TOML
     #[serde(default)]