chore: harsher punishment for failing to relay

tests/integration/metrix/keeper/keeper_intergration_test.go

@@ -592,9 +592,12 @@ var _ = Describe("update relay metrics", func() {
 			Expect(metrics[1].ExecutionTime).To(Equal(math.NewInt(349)))
 			Expect(metrics[2].ExecutionTime).To(Equal(math.NewInt(399)))
 
+			// First validator always succeeds
 			Expect(metrics[0].SuccessRate).To(Equal(palomath.LegacyDecFromFloat64(1)))
+			// Second validator always fails
 			Expect(metrics[1].SuccessRate).To(Equal(palomath.LegacyDecFromFloat64(0)))
-			Expect(metrics[2].SuccessRate).To(Equal(palomath.LegacyDecFromFloat64(.9)))
+			// Third validator fails the last message (j = 100)
+			Expect(metrics[2].SuccessRate).To(Equal(palomath.LegacyDecFromFloat64(.5)))
 		})
 	})
 })

x/metrix/keeper/keeper.go

@@ -45,6 +45,9 @@ const (
 	// cSuccessRateDecrement specifies the decrement applied to the
 	// message relay success rate for every failed attempt.
 	cSuccessRateDecrement = 0.02
+
+	// cDefaultSuccessRateScore specifies the initial score value.
+	cDefaultSuccessRateScore = 0.5
 )
 
 var _ valsettypes.OnSnapshotBuiltListener = &Keeper{}
@@ -305,15 +308,21 @@ func (k *Keeper) UpdateRelayMetrics(ctx context.Context) {
 			return true
 		}
 
-		successRateScore := 0.5
+		successRateScore := cDefaultSuccessRateScore
 		executionTimes := make([]uint64, len(history.Records))
 
 		for i, v := range history.Records {
 			executionTimes[i] = v.ExecutionSpeedInBlocks
 			if v.Success {
 				successRateScore += cSuccessRateIncrement
 			} else {
-				successRateScore -= cSuccessRateDecrement
+				// If a validator fails to relay, we bring their score back to
+				// the default value
+				if successRateScore > cDefaultSuccessRateScore {
+					successRateScore = cDefaultSuccessRateScore
+				} else {
+					successRateScore -= cSuccessRateDecrement
+				}
 			}
 		}