Refresh if the difference between blocks in the chain and ClientState exceeds this value (#47)

* refresh if block difference exceeds threold

Signed-off-by: Naohiro Yoshida <naohiro.yoshida@datachain.jp>

Author: yoshidan

e2e/config/demo/ibc-0.json

@@ -30,6 +30,7 @@
     "refreshThresholdRate": {
       "numerator": 1,
       "denominator": 2
-    }
+    },
+    "refreshBlockDifferenceThreshold": 1000
   }
 }

module/config.pb.go

@@ -191,12 +191,26 @@ func (pr *Prover) CheckRefreshRequired(counterparty core.ChainInfoICS02Querier)
 		return time.Duration(nsec) * time.Nanosecond
 	}
 	threshold := durationMulByFraction(pr.config.GetTrustingPeriod(), pr.config.GetRefreshThresholdRate())
-	needsRefresh := elapsedTime > threshold
-	if needsRefresh {
+	if elapsedTime > threshold {
 		log.GetLogger().Debug("needs refresh", "elapsedTime", elapsedTime, "threshold", threshold)
+		return true, nil
 	}
 
-	return needsRefresh, nil
+	// Check if the block difference exceeds the threshold
+	blockDiffThreshold := pr.config.RefreshBlockDifferenceThreshold
+	if blockDiffThreshold == 0 || selfQueryHeight.GetRevisionHeight() < cs.GetLatestHeight().GetRevisionHeight() {
+		return false, nil
+	}
+	blockDiff := selfQueryHeight.GetRevisionHeight() - cs.GetLatestHeight().GetRevisionHeight()
+	if blockDiff > blockDiffThreshold {
+		log.GetLogger().Debug("needs refresh due to block diff",
+			"chain", cpQueryHeight.GetRevisionHeight(),
+			"cs", cs.GetLatestHeight().GetRevisionHeight(),
+			"threshold", blockDiffThreshold)
+		return true, nil
+	}
+	return false, nil
+
 }
 
 func (pr *Prover) withProofAndValidators(height uint64, ethHeaders []*ETHHeader) (core.Header, error) {

module/prover.go

@@ -237,22 +237,48 @@ func (ts *ProverTestSuite) TestCheckRefreshRequired() {
 		Chain:  ts.prover.chain,
 		Prover: ts.prover,
 	}
+	defer func() {
+		ts.chain.latestHeight = 0
+		ts.chain.trustedHeight = 0
+	}()
+
 	now := time.Now()
 	chainHeight := clienttypes.NewHeight(0, 0)
 	csHeight := clienttypes.NewHeight(0, 0)
 	ts.chain.chainTimestamp[chainHeight] = uint64(now.Unix())
 
-	// should refresh
+	// should refresh by trusting_period
 	ts.chain.consensusStateTimestamp[csHeight] = uint64(now.Add(-51 * time.Second).UnixNano())
 	required, err := ts.prover.CheckRefreshRequired(dst)
 	ts.Require().NoError(err)
 	ts.Require().True(required)
 
-	// needless
+	// needless by trusting_period
 	ts.chain.consensusStateTimestamp[csHeight] = uint64(now.Add(-50 * time.Second).UnixNano())
 	required, err = ts.prover.CheckRefreshRequired(dst)
 	ts.Require().NoError(err)
 	ts.Require().False(required)
+
+	// should refresh by block difference
+	ts.chain.latestHeight = 2
+	ts.prover.config.RefreshBlockDifferenceThreshold = 1
+	required, err = ts.prover.CheckRefreshRequired(dst)
+	ts.Require().NoError(err)
+	ts.Require().True(required)
+
+	// needless by block difference
+	ts.prover.config.RefreshBlockDifferenceThreshold = 2
+	required, err = ts.prover.CheckRefreshRequired(dst)
+	ts.Require().NoError(err)
+	ts.Require().False(required)
+
+	// needless by invalid block difference
+	ts.chain.latestHeight = 1
+	ts.chain.trustedHeight = 3
+	ts.prover.config.RefreshBlockDifferenceThreshold = 1
+	required, err = ts.prover.CheckRefreshRequired(dst)
+	ts.Require().NoError(err)
+	ts.Require().False(required)
 }
 
 func (ts *ProverTestSuite) TestProveHostConsensusState() {

module/prover_test.go

@@ -8,7 +8,12 @@ import "gogoproto/gogo.proto";
 message ProverConfig {
   google.protobuf.Duration trusting_period = 1 [(gogoproto.nullable) = false, (gogoproto.stdduration) = true];
   google.protobuf.Duration max_clock_drift = 2 [(gogoproto.nullable) = false, (gogoproto.stdduration) = true];
+  // Fraction of the trusting period that is allowed to pass before the client is considered expired
   Fraction refresh_threshold_rate = 3;
+  // Difference in blocks to refresh.
+  // Refresh if the difference between blocks in the chain and ClientState exceeds this value.
+  // If the value is 0, no refresh decision is made.
+  uint64 refresh_block_difference_threshold = 4;
 }
 
 message Fraction {