CBG-4267 implement LWW conflict resolution for blip tester

db/hybrid_logical_vector.go

@@ -148,6 +148,11 @@ func (v Version) IsEmpty() bool {
 	return v.SourceID == "" && v.Value == 0
 }
 
+// Equal returns true if sourceID and value of the two versions are equal.
+func (v Version) Equal(other Version) bool {
+	return v.SourceID == other.SourceID && v.Value == other.Value
+}
+
 // StringForVersionDelta will take a version struct and convert the value to delta format
 // (encoding it to LE hex, stripping any 0's off the end and stripping leading 0x)
 func (v Version) StringForVersionDelta() string {
@@ -179,7 +184,8 @@ func NewHybridLogicalVector() *HybridLogicalVector {
 	}
 }
 
-func (hlv *HybridLogicalVector) Equals(other *HybridLogicalVector) bool {
+// Equal compares the full HLV to another HLV.
+func (hlv *HybridLogicalVector) Equal(other *HybridLogicalVector) bool {
 	if hlv.SourceID != other.SourceID {
 		return false
 	}
@@ -271,7 +277,7 @@ func (hlv *HybridLogicalVector) InvalidateMV() {
 		if source == hlv.SourceID {
 			continue
 		}
-		hlv.setPreviousVersion(source, value)
+		hlv.SetPreviousVersion(source, value)
 	}
 	hlv.MergeVersions = nil
 }
@@ -336,21 +342,21 @@ func (hlv *HybridLogicalVector) AddNewerVersions(otherVector *HybridLogicalVecto
 
 	// Copy incoming merge versions (previously existing merge versions will have been moved to pv by AddVersion)
 	for i, v := range otherVector.MergeVersions {
-		hlv.setMergeVersion(i, v)
+		hlv.SetMergeVersion(i, v)
 	}
 
 	if len(otherVector.PreviousVersions) != 0 {
 		// Iterate through incoming vector previous versions, update with the version from other vector
 		// for source if the local version for that source is lower
 		for i, v := range otherVector.PreviousVersions {
 			if hlv.PreviousVersions[i] == 0 {
-				hlv.setPreviousVersion(i, v)
+				hlv.SetPreviousVersion(i, v)
 			} else {
 				// if we get here then there is entry for this source in PV so we must check if its newer or not
 				otherHLVPVValue := v
 				localHLVPVValue := hlv.PreviousVersions[i]
 				if localHLVPVValue < otherHLVPVValue {
-					hlv.setPreviousVersion(i, v)
+					hlv.SetPreviousVersion(i, v)
 				}
 			}
 		}
@@ -382,16 +388,16 @@ func (hlv *HybridLogicalVector) computeMacroExpansions() []sgbucket.MacroExpansi
 	return outputSpec
 }
 
-// setPreviousVersion will take a source/version pair and add it to the HLV previous versions map
-func (hlv *HybridLogicalVector) setPreviousVersion(source string, version uint64) {
+// SetPreviousVersion will take a source/version pair and add it to the HLV previous versions map
+func (hlv *HybridLogicalVector) SetPreviousVersion(source string, version uint64) {
 	if hlv.PreviousVersions == nil {
 		hlv.PreviousVersions = make(HLVVersions)
 	}
 	hlv.PreviousVersions[source] = version
 }
 
-// setMergeVersion will take a source/version pair and add it to the HLV merge versions map
-func (hlv *HybridLogicalVector) setMergeVersion(source string, version uint64) {
+// SetMergeVersion will take a source/version pair and add it to the HLV merge versions map
+func (hlv *HybridLogicalVector) SetMergeVersion(source string, version uint64) {
 	if hlv.MergeVersions == nil {
 		hlv.MergeVersions = make(HLVVersions)
 	}

db/hybrid_logical_vector_test.go

@@ -1408,7 +1408,7 @@ func TestAddVersion(t *testing.T) {
 
 			expectedHLV, _, err := ExtractHLVFromBlipMessage(tc.expectedHLV)
 			require.NoError(t, err)
-			require.True(t, hlv.Equals(expectedHLV), "expected %#v does not match actual %#v", expectedHLV, hlv)
+			require.True(t, hlv.Equal(expectedHLV), "expected %#v does not match actual %#v", expectedHLV, hlv)
 
 		})
 	}

db/util_testing.go

@@ -878,7 +878,7 @@ func (c *DatabaseCollectionWithUser) UpsertTestDocWithVersion(ctx context.Contex
 		versions, _, err := parseVectorValues(mergeVersionsStr)
 		require.NoError(t, err, "malformed mergeVersionsStr")
 		for _, version := range versions {
-			newDocHLV.setMergeVersion(version.SourceID, version.Value)
+			newDocHLV.SetMergeVersion(version.SourceID, version.Value)
 		}
 	}
 

rest/blip_api_crud_test.go

@@ -3566,3 +3566,60 @@ func TestBlipPushRevOnResurrection(t *testing.T) {
 		})
 	}
 }
+
+func TestBlipPullConflict(t *testing.T) {
+	base.SetUpTestLogging(t, base.LevelInfo, base.KeySync, base.KeySyncMsg, base.KeySGTest)
+	btcRunner := NewBlipTesterClientRunner(t)
+
+	btcRunner.SkipSubtest[RevtreeSubtestName] = true
+
+	btcRunner.Run(func(t *testing.T, SupportedBLIPProtocols []string) {
+		rt := NewRestTesterPersistentConfig(t)
+		defer rt.Close()
+
+		const (
+			username = "alice"
+			cblBody  = `{"actor": "cbl"}`
+			sgBody   = `{"actor": "sg"}`
+		)
+		rt.CreateUser(username, []string{"*"})
+		docID := "doc1"
+		sgVersion := rt.PutDocDirectly(docID, db.Body{"actor": "sg"})
+
+		opts := &BlipTesterClientOpts{SupportedBLIPProtocols: SupportedBLIPProtocols, Username: "alice"}
+		btc := btcRunner.NewBlipTesterClientOptsWithRT(rt, opts)
+		defer btc.Close()
+
+		client := btcRunner.SingleCollection(btc.id)
+		preConflictCBLVersion := btcRunner.AddRev(btc.id, docID, EmptyDocVersion(), []byte(cblBody))
+		require.NotEqual(t, sgVersion, preConflictCBLVersion)
+
+		btcRunner.StartOneshotPull(btc.id)
+
+		require.EventuallyWithT(t, func(c *assert.CollectT) {
+			_, _, postConflictCBLVersion := client.GetDoc(docID)
+			assert.NotEqual(t, sgVersion, postConflictCBLVersion)
+		}, time.Second*10, time.Millisecond*10, "Expected sgVersion and cblVersion to be different")
+
+		postConflictDoc, postConflictHLV, postConflictVersion := client.GetDoc(docID)
+		require.Equal(t, cblBody, string(postConflictDoc))
+		// after resolving the conflict, the CBL version should remain the same but the ver of the CV is
+		// updated to be newer than the pre-conflict CBL version
+		require.Equal(t, preConflictCBLVersion.CV.SourceID, postConflictVersion.CV.SourceID)
+		require.Greater(t, postConflictVersion.CV.Value, preConflictCBLVersion.CV.Value)
+		require.Empty(t, postConflictHLV.PreviousVersions)
+		require.Equal(t, db.HLVVersions{
+			sgVersion.CV.SourceID:             sgVersion.CV.Value,
+			preConflictCBLVersion.CV.SourceID: preConflictCBLVersion.CV.Value,
+		}, postConflictHLV.MergeVersions)
+
+		btcRunner.StartPush(btc.id)
+		rt.WaitForVersion(docID, *postConflictVersion)
+
+		collection, ctx := rt.GetSingleTestDatabaseCollection()
+		bucketDoc, err := collection.GetDocument(ctx, docID, db.DocUnmarshalAll)
+		require.NoError(t, err)
+		require.True(t, bucketDoc.HLV.Equal(postConflictHLV), "Expected bucket doc HLV to match post-conflict HLV, got %v, expected %v", bucketDoc.HLV, postConflictHLV)
+	})
+
+}