Add grace period

core/state/validators/validators.go

@@ -10,6 +10,7 @@ import (
 	"github.com/MinterTeam/minter-go-node/core/types"
 	"github.com/MinterTeam/minter-go-node/rlp"
 	"github.com/MinterTeam/minter-go-node/tree"
+	"github.com/MinterTeam/minter-go-node/upgrades"
 
 	"math/big"
 )
@@ -101,7 +102,10 @@ func (v *Validators) SetValidatorAbsent(height uint64, address types.TmAddress)
 	validator.SetAbsent(height)
 
 	if validator.CountAbsentTimes() > ValidatorMaxAbsentTimes {
-		v.punishValidator(height, address)
+		if !upgrades.IsGraceBlock(height) {
+			v.punishValidator(height, address)
+		}
+
 		v.turnValidatorOff(address)
 	}
 }

upgrades/grace.go

@@ -0,0 +1,28 @@
+package upgrades
+
+var gracePeriods = []*gracePeriod{
+	newGracePeriod(1, 120),
+}
+
+func IsGraceBlock(block uint64) bool {
+	for _, gp := range gracePeriods {
+		if gp.isApplicable(block) {
+			return true
+		}
+	}
+
+	return false
+}
+
+type gracePeriod struct {
+	from uint64
+	to   uint64
+}
+
+func (gp *gracePeriod) isApplicable(block uint64) bool {
+	return block >= gp.from && block <= gp.to
+}
+
+func newGracePeriod(from uint64, to uint64) *gracePeriod {
+	return &gracePeriod{from: from, to: to}
+}