types: add default values for the synchrony parameters

types/genesis.go

@@ -113,7 +113,10 @@ func (genDoc *GenesisDoc) ValidateAndComplete() error {
 
 	if genDoc.ConsensusParams == nil {
 		genDoc.ConsensusParams = DefaultConsensusParams()
-	} else if err := genDoc.ConsensusParams.ValidateConsensusParams(); err != nil {
+	}
+	genDoc.ConsensusParams.Complete()
+
+	if err := genDoc.ConsensusParams.ValidateConsensusParams(); err != nil {
 		return err
 	}
 

types/params.go

@@ -128,11 +128,12 @@ func DefaultVersionParams() VersionParams {
 }
 
 func DefaultSynchronyParams() SynchronyParams {
-	// TODO(@wbanfield): Determine experimental values for these defaults
-	// https://github.com/tendermint/tendermint/issues/7202
 	return SynchronyParams{
-		Precision:    500 * time.Millisecond,
-		MessageDelay: 3 * time.Second,
+		// 505ms was selected as the default to enable chains that have validators in
+		// mixed leap-second handling environments.
+		// For more information, see: https://github.com/tendermint/tendermint/issues/7724
+		Precision:    505 * time.Millisecond,
+		MessageDelay: 12 * time.Second,
 	}
 }
 
@@ -145,6 +146,12 @@ func (val *ValidatorParams) IsValidPubkeyType(pubkeyType string) bool {
 	return false
 }
 
+func (params *ConsensusParams) Complete() {
+	if params.Synchrony.MessageDelay == 0 && params.Synchrony.Precision == 0 {
+		params.Synchrony = DefaultSynchronyParams()
+	}
+}
+
 // Validate validates the ConsensusParams to ensure all values are within their
 // allowed limits, and returns an error if they are not.
 func (params ConsensusParams) ValidateConsensusParams() error {