types: fix evidence timestamp calculation (#5032)

depending on the votes order in DuplicateVoteEvidence is arbitrary.
we should always choose the latest timestamp.

Closes #5030

types/evidence.go

@@ -310,9 +310,9 @@ func (dve *DuplicateVoteEvidence) Height() int64 {
 	return dve.VoteA.Height
 }
 
-// Time returns the time the evidence was created.
+// Time returns time of the latest vote.
 func (dve *DuplicateVoteEvidence) Time() time.Time {
-	return dve.VoteA.Timestamp
+	return maxTime(dve.VoteA.Timestamp, dve.VoteB.Timestamp)
 }
 
 // Address returns the address of the validator.
@@ -677,8 +677,10 @@ OUTER_LOOP:
 
 func (ev ConflictingHeadersEvidence) Height() int64 { return ev.H1.Height }
 
-// XXX: this is not the time of equivocation
-func (ev ConflictingHeadersEvidence) Time() time.Time { return ev.H1.Time }
+// Time returns time of the latest header.
+func (ev ConflictingHeadersEvidence) Time() time.Time {
+	return maxTime(ev.H1.Time, ev.H2.Time)
+}
 
 func (ev ConflictingHeadersEvidence) Address() []byte {
 	panic("use ConflictingHeadersEvidence#Split to split evidence into individual pieces")
@@ -833,6 +835,7 @@ func (e PhantomValidatorEvidence) Height() int64 {
 	return e.Vote.Height
 }
 
+// Time returns the Vote's timestamp.
 func (e PhantomValidatorEvidence) Time() time.Time {
 	return e.Vote.Timestamp
 }
@@ -954,8 +957,9 @@ func (e LunaticValidatorEvidence) Height() int64 {
 	return e.Header.Height
 }
 
+// Time returns the maximum between the header's time and vote's time.
 func (e LunaticValidatorEvidence) Time() time.Time {
-	return e.Header.Time
+	return maxTime(e.Header.Time, e.Vote.Timestamp)
 }
 
 func (e LunaticValidatorEvidence) Address() []byte {
@@ -1145,8 +1149,9 @@ func (e PotentialAmnesiaEvidence) Height() int64 {
 	return e.VoteA.Height
 }
 
+// Time returns time of the latest vote.
 func (e PotentialAmnesiaEvidence) Time() time.Time {
-	return e.VoteA.Timestamp
+	return maxTime(e.VoteA.Timestamp, e.VoteB.Timestamp)
 }
 
 func (e PotentialAmnesiaEvidence) Address() []byte {
@@ -1340,7 +1345,7 @@ func (e ProofOfLockChange) Height() int64 {
 	return e.Votes[0].Height
 }
 
-// returns the time of the last vote
+// Time returns time of the latest vote.
 func (e ProofOfLockChange) Time() time.Time {
 	latest := e.Votes[0].Timestamp
 	for _, vote := range e.Votes {
@@ -1770,3 +1775,10 @@ func NewMockPOLC(height int64, time time.Time, pubKey crypto.PubKey) ProofOfLock
 		PubKey: pubKey,
 	}
 }
+
+func maxTime(t1 time.Time, t2 time.Time) time.Time {
+	if t1.After(t2) {
+		return t1
+	}
+	return t2
+}

types/evidence_test.go

@@ -80,6 +80,12 @@ func TestDuplicatedVoteEvidence(t *testing.T) {
 
 	assert.True(t, ev.Equal(ev))
 	assert.False(t, ev.Equal(&DuplicateVoteEvidence{}))
+
+	maxTime := ev.VoteB.Timestamp
+	if ev.VoteA.Timestamp.After(ev.VoteB.Timestamp) {
+		maxTime = ev.VoteA.Timestamp
+	}
+	assert.Equal(t, maxTime, ev.Time(), "expected time of the latest vote")
 }
 
 func TestEvidenceList(t *testing.T) {
@@ -152,7 +158,7 @@ func randomDuplicatedVoteEvidence(t *testing.T) *DuplicateVoteEvidence {
 	const chainID = "mychain"
 	return &DuplicateVoteEvidence{
 		VoteA: makeVote(t, val, chainID, 0, 10, 2, 1, blockID, defaultVoteTime),
-		VoteB: makeVote(t, val, chainID, 0, 10, 2, 1, blockID2, defaultVoteTime),
+		VoteB: makeVote(t, val, chainID, 0, 10, 2, 1, blockID2, defaultVoteTime.Add(1*time.Minute)),
 	}
 }
 
@@ -223,7 +229,7 @@ func TestLunaticValidatorEvidence(t *testing.T) {
 	}
 
 	assert.Equal(t, header.Height, ev.Height())
-	assert.Equal(t, bTime, ev.Time())
+	assert.Equal(t, defaultVoteTime, ev.Time())
 	assert.EqualValues(t, vote.ValidatorAddress, ev.Address())
 	assert.NotEmpty(t, ev.Hash())
 	assert.NotEmpty(t, ev.Bytes())
@@ -330,7 +336,7 @@ func TestConflictingHeadersEvidence(t *testing.T) {
 	})
 
 	assert.Equal(t, height, ev.Height())
-	// assert.Equal(t, bTime, ev.Time())
+	assert.Equal(t, ev.H2.Time, ev.Time())
 	assert.NotEmpty(t, ev.Hash())
 	assert.NotEmpty(t, ev.Bytes())
 	assert.NoError(t, ev.VerifyComposite(header1, valSet))
@@ -350,7 +356,7 @@ func TestPotentialAmnesiaEvidence(t *testing.T) {
 		blockID  = makeBlockID(tmhash.Sum([]byte("blockhash")), math.MaxInt32, tmhash.Sum([]byte("partshash")))
 		blockID2 = makeBlockID(tmhash.Sum([]byte("blockhash2")), math.MaxInt32, tmhash.Sum([]byte("partshash")))
 		vote1    = makeVote(t, val, chainID, 0, height, 0, 2, blockID, defaultVoteTime)
-		vote2    = makeVote(t, val, chainID, 0, height, 1, 2, blockID2, defaultVoteTime)
+		vote2    = makeVote(t, val, chainID, 0, height, 1, 2, blockID2, defaultVoteTime.Add(1*time.Minute))
 	)
 
 	ev := &PotentialAmnesiaEvidence{
@@ -359,7 +365,7 @@ func TestPotentialAmnesiaEvidence(t *testing.T) {
 	}
 
 	assert.Equal(t, height, ev.Height())
-	// assert.Equal(t, bTime, ev.Time())
+	assert.Equal(t, vote2.Timestamp, ev.Time())
 	assert.EqualValues(t, vote1.ValidatorAddress, ev.Address())
 	assert.NotEmpty(t, ev.Hash())
 	assert.NotEmpty(t, ev.Bytes())