Separate persisted responses without knowing their revision to prevent duplicating state during linearization

Signed-off-by: Marek Siarkowicz <siarkowicz@google.com>

tests/robustness/model/describe.go

@@ -28,8 +28,11 @@ func describeEtcdResponse(request EtcdRequest, response MaybeEtcdResponse) strin
 	if response.ClientError != "" {
 		return fmt.Sprintf("err: %q", response.ClientError)
 	}
-	if response.PartialResponse {
-		return fmt.Sprintf("unknown, rev: %d", response.Revision)
+	if response.Persisted {
+		if response.PersistedRevision != 0 {
+			return fmt.Sprintf("unknown, rev: %d", response.PersistedRevision)
+		}
+		return fmt.Sprintf("unknown")
 	}
 	switch request.Type {
 	case Range:

tests/robustness/model/deterministic.go

@@ -123,7 +123,7 @@ func (s EtcdState) Step(request EtcdRequest) (EtcdState, MaybeEtcdResponse) {
 		if request.Range.Revision < newState.CompactRevision {
 			return newState, MaybeEtcdResponse{EtcdResponse: EtcdResponse{ClientError: mvcc.ErrCompacted.Error()}}
 		}
-		return newState, MaybeEtcdResponse{PartialResponse: true, EtcdResponse: EtcdResponse{Revision: newState.Revision}}
+		return newState, MaybeEtcdResponse{Persisted: true, PersistedRevision: newState.Revision}
 	case Txn:
 		failure := false
 		for _, cond := range request.Txn.Conditions {
@@ -351,15 +351,17 @@ type LeaseRevokeRequest struct {
 }
 type DefragmentRequest struct{}
 
-// MaybeEtcdResponse extends EtcdResponse to represent partial or failed responses.
-// Possible states:
-// * Normal response. Only EtcdResponse is set.
-// * Partial response. The EtcdResponse.Revision and PartialResponse are set.
-// * Failed response. Only Err is set.
+// MaybeEtcdResponse extends EtcdResponse to include partial information about responses to a request.
+// Possible response state information:
+// * Normal response. Client observed response. Only EtcdResponse is set.
+// * Persisted. Client didn't observe response, but we know it was persisted by etcd. Only Persisted is set
+// * Persisted with Revision. Client didn't observe response, but we know that it was persisted, and it's revision. Both Persisted and PersistedRevision is set.
+// * Error response. Client observed error, but we don't know if it was persisted. Only Error is set.
 type MaybeEtcdResponse struct {
 	EtcdResponse
-	PartialResponse bool
-	Error           string
+	Persisted         bool
+	PersistedRevision int64
+	Error             string
 }
 
 var ErrEtcdFutureRev = errors.New("future rev")
@@ -376,7 +378,15 @@ type EtcdResponse struct {
 }
 
 func Match(r1, r2 MaybeEtcdResponse) bool {
-	return ((r1.PartialResponse || r2.PartialResponse) && (r1.Revision == r2.Revision)) || reflect.DeepEqual(r1, r2)
+	r1Revision := r1.Revision
+	if r1.Persisted {
+		r1Revision = r1.PersistedRevision
+	}
+	r2Revision := r2.Revision
+	if r2.Persisted {
+		r2Revision = r2.PersistedRevision
+	}
+	return (r1.Persisted && r1.PersistedRevision == 0) || (r2.Persisted && r2.PersistedRevision == 0) || ((r1.Persisted || r2.Persisted) && (r1.Error != "" || r2.Error != "" || r1Revision == r2Revision)) || reflect.DeepEqual(r1, r2)
 }
 
 type TxnResponse struct {

tests/robustness/model/history.go

@@ -365,7 +365,7 @@ func failedResponse(err error) MaybeEtcdResponse {
 }
 
 func partialResponse(revision int64) MaybeEtcdResponse {
-	return MaybeEtcdResponse{PartialResponse: true, EtcdResponse: EtcdResponse{Revision: revision}}
+	return MaybeEtcdResponse{Persisted: true, PersistedRevision: revision}
 }
 
 func putRequest(key, value string) EtcdRequest {

tests/robustness/model/non_deterministic.go

@@ -58,17 +58,19 @@ func (states nonDeterministicState) apply(request EtcdRequest, response MaybeEtc
 	var newStates nonDeterministicState
 	switch {
 	case response.Error != "":
-		newStates = states.stepFailedResponse(request)
-	case response.PartialResponse:
-		newStates = states.applyResponseRevision(request, response.EtcdResponse.Revision)
+		newStates = states.applyFailedRequest(request)
+	case response.Persisted && response.PersistedRevision == 0:
+		newStates = states.applyPersistedRequest(request)
+	case response.Persisted && response.PersistedRevision != 0:
+		newStates = states.applyPersistedRequestWithRevision(request, response.PersistedRevision)
 	default:
-		newStates = states.applySuccessfulResponse(request, response.EtcdResponse)
+		newStates = states.applyRequestWithResponse(request, response.EtcdResponse)
 	}
 	return len(newStates) > 0, newStates
 }
 
-// stepFailedResponse duplicates number of states by considering both cases, request was persisted and request was lost.
-func (states nonDeterministicState) stepFailedResponse(request EtcdRequest) nonDeterministicState {
+// applyFailedRequest returns both the original states and states with applied request. It considers both cases, request was persisted and request was lost.
+func (states nonDeterministicState) applyFailedRequest(request EtcdRequest) nonDeterministicState {
 	newStates := make(nonDeterministicState, 0, len(states)*2)
 	for _, s := range states {
 		newStates = append(newStates, s)
@@ -80,8 +82,18 @@ func (states nonDeterministicState) stepFailedResponse(request EtcdRequest) nonD
 	return newStates
 }
 
-// applyResponseRevision filters possible states by leaving ony states that would return proper revision.
-func (states nonDeterministicState) applyResponseRevision(request EtcdRequest, responseRevision int64) nonDeterministicState {
+// applyPersistedRequest applies request to all possible states.
+func (states nonDeterministicState) applyPersistedRequest(request EtcdRequest) nonDeterministicState {
+	newStates := make(nonDeterministicState, 0, len(states))
+	for _, s := range states {
+		newState, _ := s.Step(request)
+		newStates = append(newStates, newState)
+	}
+	return newStates
+}
+
+// applyPersistedRequestWithRevision applies request to all possible states, but leaves only states that would return proper revision.
+func (states nonDeterministicState) applyPersistedRequestWithRevision(request EtcdRequest, responseRevision int64) nonDeterministicState {
 	newStates := make(nonDeterministicState, 0, len(states))
 	for _, s := range states {
 		newState, modelResponse := s.Step(request)
@@ -92,8 +104,8 @@ func (states nonDeterministicState) applyResponseRevision(request EtcdRequest, r
 	return newStates
 }
 
-// applySuccessfulResponse filters possible states by leaving ony states that would respond correctly.
-func (states nonDeterministicState) applySuccessfulResponse(request EtcdRequest, response EtcdResponse) nonDeterministicState {
+// applyRequestWithResponse applies request to all possible states, but leaves only state that would return proper response.
+func (states nonDeterministicState) applyRequestWithResponse(request EtcdRequest, response EtcdResponse) nonDeterministicState {
 	newStates := make(nonDeterministicState, 0, len(states))
 	for _, s := range states {
 		newState, modelResponse := s.Step(request)

tests/robustness/model/non_deterministic_test.go

@@ -391,7 +391,7 @@ func TestModelResponseMatch(t *testing.T) {
 		},
 		{
 			resp1:       getResponse("key", "a", 1, 1),
-			resp2:       partialResponse(0),
+			resp2:       partialResponse(2),
 			expectMatch: false,
 		},
 		{
@@ -416,9 +416,14 @@ func TestModelResponseMatch(t *testing.T) {
 		},
 		{
 			resp1:       putResponse(3),
-			resp2:       partialResponse(0),
+			resp2:       partialResponse(1),
 			expectMatch: false,
 		},
+		{
+			resp1:       putResponse(3),
+			resp2:       partialResponse(0),
+			expectMatch: true,
+		},
 		{
 			resp1:       deleteResponse(1, 5),
 			resp2:       deleteResponse(1, 5),
@@ -446,13 +451,18 @@ func TestModelResponseMatch(t *testing.T) {
 		},
 		{
 			resp1:       deleteResponse(0, 5),
-			resp2:       partialResponse(0),
+			resp2:       partialResponse(4),
 			expectMatch: false,
 		},
+		{
+			resp1:       deleteResponse(0, 5),
+			resp2:       partialResponse(0),
+			expectMatch: true,
+		},
 		{
 			resp1:       deleteResponse(1, 5),
 			resp2:       partialResponse(0),
-			expectMatch: false,
+			expectMatch: true,
 		},
 		{
 			resp1:       deleteResponse(0, 5),
@@ -491,12 +501,72 @@ func TestModelResponseMatch(t *testing.T) {
 		},
 		{
 			resp1:       compareRevisionAndPutResponse(true, 7),
-			resp2:       partialResponse(0),
+			resp2:       partialResponse(4),
+			expectMatch: false,
+		},
+		{
+			resp1:       compareRevisionAndPutResponse(false, 7),
+			resp2:       partialResponse(3),
 			expectMatch: false,
 		},
 		{
 			resp1:       compareRevisionAndPutResponse(false, 7),
 			resp2:       partialResponse(0),
+			expectMatch: true,
+		},
+		{
+			resp1:       MaybeEtcdResponse{EtcdResponse: EtcdResponse{Revision: 1, Txn: &TxnResponse{Failure: false, Results: []EtcdOperationResult{{Deleted: 1}}}}},
+			resp2:       failedResponse(errors.New("failed request")),
+			expectMatch: false,
+		},
+		{
+			resp1:       failedResponse(errors.New("failed request 1")),
+			resp2:       failedResponse(errors.New("failed request 2")),
+			expectMatch: false,
+		},
+		{
+			resp1:       failedResponse(errors.New("failed request")),
+			resp2:       failedResponse(errors.New("failed request")),
+			expectMatch: true,
+		},
+		{
+			resp1:       putResponse(2),
+			resp2:       MaybeEtcdResponse{Persisted: true},
+			expectMatch: true,
+		},
+		{
+			resp1:       putResponse(2),
+			resp2:       MaybeEtcdResponse{Persisted: true, PersistedRevision: 2},
+			expectMatch: true,
+		},
+		{
+			resp1:       putResponse(2),
+			resp2:       MaybeEtcdResponse{Persisted: true, PersistedRevision: 3},
+			expectMatch: false,
+		},
+		{
+			resp1:       failedResponse(errors.New("failed request")),
+			resp2:       MaybeEtcdResponse{Persisted: true},
+			expectMatch: true,
+		},
+		{
+			resp1:       failedResponse(errors.New("failed request")),
+			resp2:       MaybeEtcdResponse{Persisted: true, PersistedRevision: 2},
+			expectMatch: true,
+		},
+		{
+			resp1:       MaybeEtcdResponse{Persisted: true},
+			resp2:       MaybeEtcdResponse{Persisted: true, PersistedRevision: 2},
+			expectMatch: true,
+		},
+		{
+			resp1:       MaybeEtcdResponse{Persisted: true, PersistedRevision: 2},
+			resp2:       MaybeEtcdResponse{Persisted: true, PersistedRevision: 2},
+			expectMatch: true,
+		},
+		{
+			resp1:       MaybeEtcdResponse{Persisted: true, PersistedRevision: 1},
+			resp2:       MaybeEtcdResponse{Persisted: true, PersistedRevision: 2},
 			expectMatch: false,
 		},
 	}

tests/robustness/validate/operations.go

@@ -83,7 +83,7 @@ func filterSerializableOperations(clients []report.ClientReport) []porcupine.Ope
 }
 
 func validateSerializableRead(lg *zap.Logger, replay *model.EtcdReplay, request model.EtcdRequest, response model.MaybeEtcdResponse) error {
-	if response.PartialResponse || response.Error != "" {
+	if response.Persisted || response.Error != "" {
 		return nil
 	}
 	state, err := replay.StateForRevision(request.Range.Revision)

tests/robustness/validate/patch_history.go

@@ -76,6 +76,7 @@ func patchOperations(operations []porcupine.Operation, watchEvents map[model.Eve
 			newOperations = append(newOperations, op)
 			continue
 		}
+		var resourceVersion int64
 		if op.Call <= lastObservedOperation.Call {
 			matchingEvent := matchWatchEvent(request.Txn, watchEvents)
 			if matchingEvent != nil {
@@ -84,7 +85,7 @@ func patchOperations(operations []porcupine.Operation, watchEvents map[model.Eve
 				if eventTime < op.Return {
 					op.Return = eventTime
 				}
-				op.Output = model.MaybeEtcdResponse{PartialResponse: true, EtcdResponse: model.EtcdResponse{Revision: matchingEvent.Revision}}
+				resourceVersion = matchingEvent.Revision
 			}
 		}
 		persistedReturnTime := matchReturnTime(request, persistedOperations)
@@ -94,9 +95,17 @@ func patchOperations(operations []porcupine.Operation, watchEvents map[model.Eve
 				op.Return = *persistedReturnTime
 			}
 		}
-		if persistedReturnTime == nil && canBeDiscarded(request.Txn) {
-			// Remove non persisted operations
-			continue
+		if isUniqueTxn(request.Txn) {
+			if persistedReturnTime == nil {
+				// Remove non persisted operations
+				continue
+			} else {
+				if resourceVersion != 0 {
+					op.Output = model.MaybeEtcdResponse{Persisted: true, PersistedRevision: resourceVersion}
+				} else {
+					op.Output = model.MaybeEtcdResponse{Persisted: true}
+				}
+			}
 		}
 		// Leave operation as it is as we cannot discard it.
 		newOperations = append(newOperations, op)
@@ -137,12 +146,8 @@ func matchWatchEvent(request *model.TxnRequest, watchEvents map[model.Event]clie
 	return nil
 }
 
-func canBeDiscarded(request *model.TxnRequest) bool {
-	return operationsCanBeDiscarded(request.OperationsOnSuccess) && operationsCanBeDiscarded(request.OperationsOnFailure)
-}
-
-func operationsCanBeDiscarded(ops []model.EtcdOperation) bool {
-	return hasUniqueWriteOperation(ops) || !hasWriteOperation(ops)
+func isUniqueTxn(request *model.TxnRequest) bool {
+	return (hasUniqueWriteOperation(request.OperationsOnSuccess) || !hasWriteOperation(request.OperationsOnSuccess)) && (hasUniqueWriteOperation(request.OperationsOnFailure) || !hasWriteOperation(request.OperationsOnFailure))
 }
 
 func hasWriteOperation(ops []model.EtcdOperation) bool {

tests/robustness/validate/patch_history_test.go

@@ -67,7 +67,7 @@ func TestPatchHistory(t *testing.T) {
 				putRequest("key", "value"),
 			},
 			expectedRemainingOperations: []porcupine.Operation{
-				{Return: 1000000000, Output: model.MaybeEtcdResponse{Error: "failed"}},
+				{Return: 1000000000, Output: model.MaybeEtcdResponse{Persisted: true}},
 			},
 		},
 		{
@@ -81,7 +81,7 @@ func TestPatchHistory(t *testing.T) {
 				putRequest("key2", "value"),
 			},
 			expectedRemainingOperations: []porcupine.Operation{
-				{Return: 3, Output: model.MaybeEtcdResponse{Error: "failed"}},
+				{Return: 3, Output: model.MaybeEtcdResponse{Persisted: true}},
 				{Return: 4, Output: putResponse(model.EtcdOperationResult{})},
 			},
 		},
@@ -95,7 +95,7 @@ func TestPatchHistory(t *testing.T) {
 			},
 			watchOperations: watchPutEvent("key", "value", 2, 3),
 			expectedRemainingOperations: []porcupine.Operation{
-				{Return: 3, Output: model.MaybeEtcdResponse{PartialResponse: true, EtcdResponse: model.EtcdResponse{Revision: 2}}},
+				{Return: 3, Output: model.MaybeEtcdResponse{Persisted: true, PersistedRevision: 2}},
 			},
 		},
 		{
@@ -133,7 +133,7 @@ func TestPatchHistory(t *testing.T) {
 				putRequestWithLease("key", "value", 123),
 			},
 			expectedRemainingOperations: []porcupine.Operation{
-				{Return: 1000000000, Output: model.MaybeEtcdResponse{Error: "failed"}},
+				{Return: 1000000000, Output: model.MaybeEtcdResponse{Persisted: true}},
 			},
 		},
 		{
@@ -147,7 +147,7 @@ func TestPatchHistory(t *testing.T) {
 				putRequestWithLease("key2", "value", 234),
 			},
 			expectedRemainingOperations: []porcupine.Operation{
-				{Return: 3, Output: model.MaybeEtcdResponse{Error: "failed"}},
+				{Return: 3, Output: model.MaybeEtcdResponse{Persisted: true}},
 				{Return: 4, Output: putResponse(model.EtcdOperationResult{})},
 			},
 		},
@@ -212,7 +212,7 @@ func TestPatchHistory(t *testing.T) {
 				putRequest("key", "value"),
 			},
 			expectedRemainingOperations: []porcupine.Operation{
-				{Return: 1000000000, Output: model.MaybeEtcdResponse{Error: "failed"}},
+				{Return: 1000000000, Output: model.MaybeEtcdResponse{Persisted: true}},
 			},
 		},
 		{
@@ -267,7 +267,7 @@ func TestPatchHistory(t *testing.T) {
 				putRequest("key", "value"),
 			},
 			expectedRemainingOperations: []porcupine.Operation{
-				{Return: 1000000000, Output: model.MaybeEtcdResponse{Error: "failed"}},
+				{Return: 1000000000, Output: model.MaybeEtcdResponse{Persisted: true}},
 			},
 		},
 		{