Fixed a bug in the reported virtual changeset, and modified the test to verify it

domain/consensus/consensus.go

@@ -916,7 +916,7 @@ func (s *consensus) ResolveVirtual(progressReportCallback func(uint64, uint64))
 		// release the lock each time we resolve 100 blocks.
 		// Note: maxBlocksToResolve should be smaller than `params.FinalityDuration` in order to avoid a situation
 		// where UpdatePruningPointByVirtual skips a pruning point.
-		isCompletelyResolved, err := s.resolveVirtualChunkWithLock(100)
+		_, isCompletelyResolved, err := s.resolveVirtualChunkWithLock(100)
 		if err != nil {
 			return err
 		}
@@ -928,37 +928,37 @@ func (s *consensus) ResolveVirtual(progressReportCallback func(uint64, uint64))
 	return nil
 }
 
-func (s *consensus) resolveVirtualChunkWithLock(maxBlocksToResolve uint64) (bool, error) {
+func (s *consensus) resolveVirtualChunkWithLock(maxBlocksToResolve uint64) (*externalapi.VirtualChangeSet, bool, error) {
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
 	return s.resolveVirtualNoLock(maxBlocksToResolve)
 }
 
-func (s *consensus) resolveVirtualNoLock(maxBlocksToResolve uint64) (bool, error) {
+func (s *consensus) resolveVirtualNoLock(maxBlocksToResolve uint64) (*externalapi.VirtualChangeSet, bool, error) {
 	virtualChangeSet, isCompletelyResolved, err := s.consensusStateManager.ResolveVirtual(maxBlocksToResolve)
 	if err != nil {
-		return false, err
+		return nil, false, err
 	}
 	s.virtualNotUpdated = !isCompletelyResolved
 
 	stagingArea := model.NewStagingArea()
 	err = s.pruningManager.UpdatePruningPointByVirtual(stagingArea)
 	if err != nil {
-		return false, err
+		return nil, false, err
 	}
 
 	err = staging.CommitAllChanges(s.databaseContext, stagingArea)
 	if err != nil {
-		return false, err
+		return nil, false, err
 	}
 
 	err = s.sendVirtualChangedEvent(virtualChangeSet, true)
 	if err != nil {
-		return false, err
+		return nil, false, err
 	}
 
-	return isCompletelyResolved, nil
+	return virtualChangeSet, isCompletelyResolved, nil
 }
 
 func (s *consensus) BuildPruningPointProof() (*externalapi.PruningPointProof, error) {

domain/consensus/model/testapi/test_consensus.go

@@ -49,7 +49,7 @@ type TestConsensus interface {
 		*externalapi.VirtualChangeSet, error)
 	UpdatePruningPointByVirtual() error
 
-	ResolveVirtualWithMaxParam(maxBlocksToResolve uint64) (bool, error)
+	ResolveVirtualWithMaxParam(maxBlocksToResolve uint64) (*externalapi.VirtualChangeSet, bool, error)
 
 	MineJSON(r io.Reader, blockType MineJSONBlockType) (tips []*externalapi.DomainHash, err error)
 	ToJSON(w io.Writer) error

domain/consensus/processes/consensusstatemanager/resolve.go

@@ -203,7 +203,7 @@ func (csm *consensusStateManager) ResolveVirtual(maxBlocksToResolve uint64) (*ex
 	}
 
 	selectedParentChainChanges, err := csm.dagTraversalManager.
-		CalculateChainPath(updateVirtualStagingArea, previousVirtualSelectedParent, pendingTip)
+		CalculateChainPath(updateVirtualStagingArea, previousVirtualSelectedParent, processingPoint)
 	if err != nil {
 		return nil, false, err
 	}

domain/consensus/processes/consensusstatemanager/resolve_virtual_test.go

@@ -56,7 +56,7 @@ func TestAddBlockBetweenResolveVirtualCalls(t *testing.T) {
 		}
 
 		// Resolve one step
-		_, err = tc.ResolveVirtualWithMaxParam(2)
+		_, _, err = tc.ResolveVirtualWithMaxParam(2)
 		if err != nil {
 			t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 		}
@@ -75,7 +75,7 @@ func TestAddBlockBetweenResolveVirtualCalls(t *testing.T) {
 		}
 
 		// Resolve one more step
-		isCompletelyResolved, err := tc.ResolveVirtualWithMaxParam(2)
+		_, isCompletelyResolved, err := tc.ResolveVirtualWithMaxParam(2)
 		if err != nil {
 			t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 		}
@@ -89,7 +89,7 @@ func TestAddBlockBetweenResolveVirtualCalls(t *testing.T) {
 
 		// Complete resolving virtual
 		for !isCompletelyResolved {
-			isCompletelyResolved, err = tc.ResolveVirtualWithMaxParam(2)
+			_, isCompletelyResolved, err = tc.ResolveVirtualWithMaxParam(2)
 			if err != nil {
 				t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 			}
@@ -142,7 +142,7 @@ func TestAddGenesisChildAfterOneResolveVirtualCall(t *testing.T) {
 		}
 
 		// Resolve one step
-		isCompletelyResolved, err := tc.ResolveVirtualWithMaxParam(2)
+		_, isCompletelyResolved, err := tc.ResolveVirtualWithMaxParam(2)
 		if err != nil {
 			t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 		}
@@ -154,7 +154,7 @@ func TestAddGenesisChildAfterOneResolveVirtualCall(t *testing.T) {
 
 		// Complete resolving virtual
 		for !isCompletelyResolved {
-			isCompletelyResolved, err = tc.ResolveVirtualWithMaxParam(2)
+			_, isCompletelyResolved, err = tc.ResolveVirtualWithMaxParam(2)
 			if err != nil {
 				t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 			}
@@ -207,13 +207,13 @@ func TestAddGenesisChildAfterTwoResolveVirtualCalls(t *testing.T) {
 		}
 
 		// Resolve one step
-		_, err = tc.ResolveVirtualWithMaxParam(2)
+		_, _, err = tc.ResolveVirtualWithMaxParam(2)
 		if err != nil {
 			t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 		}
 
 		// Resolve one more step
-		isCompletelyResolved, err := tc.ResolveVirtualWithMaxParam(2)
+		_, isCompletelyResolved, err := tc.ResolveVirtualWithMaxParam(2)
 		if err != nil {
 			t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 		}
@@ -225,7 +225,7 @@ func TestAddGenesisChildAfterTwoResolveVirtualCalls(t *testing.T) {
 
 		// Complete resolving virtual
 		for !isCompletelyResolved {
-			isCompletelyResolved, err = tc.ResolveVirtualWithMaxParam(2)
+			_, isCompletelyResolved, err = tc.ResolveVirtualWithMaxParam(2)
 			if err != nil {
 				t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 			}
@@ -296,22 +296,45 @@ func TestResolveVirtualBackAndForthReorgs(t *testing.T) {
 		printUtxoDiffChildren(t, tc, hashes, blocks)
 		verifyUtxoDiffPaths(t, tc, hashes)
 
+		previousVirtualSelectedParent, err := tc.GetVirtualSelectedParent()
+		if err != nil {
+			t.Fatal(err)
+		}
+
 		// Resolve one step
-		_, err = tc.ResolveVirtualWithMaxParam(3)
+		virtualChangeSet, _, err := tc.ResolveVirtualWithMaxParam(3)
 		if err != nil {
 			printUtxoDiffChildren(t, tc, hashes, blocks)
 			t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 		}
 
+		newVirtualSelectedParent, err := tc.GetVirtualSelectedParent()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Make sure the reported change-set is compatible with actual changes.
+		// Checking this for one call should suffice to avoid possible bugs.
+		reportedPreviousVirtualSelectedParent := virtualChangeSet.VirtualSelectedParentChainChanges.Removed[0]
+		reportedNewVirtualSelectedParent := virtualChangeSet.VirtualSelectedParentChainChanges.
+			Added[len(virtualChangeSet.VirtualSelectedParentChainChanges.Added)-1]
+
+		if !previousVirtualSelectedParent.Equal(reportedPreviousVirtualSelectedParent) {
+			t.Fatalf("The reported changeset is incompatible with actual changes")
+		}
+		if !newVirtualSelectedParent.Equal(reportedNewVirtualSelectedParent) {
+			t.Fatalf("The reported changeset is incompatible with actual changes")
+		}
+
 		// Resolve one more step
-		isCompletelyResolved, err := tc.ResolveVirtualWithMaxParam(3)
+		_, isCompletelyResolved, err := tc.ResolveVirtualWithMaxParam(3)
 		if err != nil {
 			t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 		}
 
 		// Complete resolving virtual
 		for !isCompletelyResolved {
-			isCompletelyResolved, err = tc.ResolveVirtualWithMaxParam(3)
+			_, isCompletelyResolved, err = tc.ResolveVirtualWithMaxParam(3)
 			if err != nil {
 				t.Fatalf("Error resolving virtual in re-org chain: %+v", err)
 			}

domain/consensus/test_consensus.go

@@ -112,7 +112,7 @@ func (tc *testConsensus) AddUTXOInvalidBlock(parentHashes []*externalapi.DomainH
 	return consensushashing.BlockHash(block), virtualChangeSet, nil
 }
 
-func (tc *testConsensus) ResolveVirtualWithMaxParam(maxBlocksToResolve uint64) (bool, error) {
+func (tc *testConsensus) ResolveVirtualWithMaxParam(maxBlocksToResolve uint64) (*externalapi.VirtualChangeSet, bool, error) {
 	tc.lock.Lock()
 	defer tc.lock.Unlock()