Add Maybe to the end bound of proofs (Part 2) (#1813)

Co-authored-by: Dan Laine <daniel.laine@avalabs.org>

proto/sync/sync.proto

@@ -71,7 +71,7 @@ message GetChangeProofRequest {
   bytes start_root_hash = 1;
   bytes end_root_hash = 2;
   bytes start_key = 3;
-  bytes end_key = 4;
+  MaybeBytes end_key = 4;
   uint32 key_limit = 5;
 }
 
@@ -104,7 +104,7 @@ message SyncGetRangeProofRequest {
 message GetRangeProofRequest {
   bytes root_hash = 1;
   bytes start_key = 2;
-  bytes end_key = 3;
+  MaybeBytes end_key = 3;
   uint32 key_limit = 4;
 }
 

x/merkledb/db.go

@@ -61,7 +61,7 @@ type ChangeProofer interface {
 		startRootID ids.ID,
 		endRootID ids.ID,
 		start []byte,
-		end []byte,
+		end Maybe[[]byte],
 		maxLength int,
 	) (*ChangeProof, error)
 
@@ -97,8 +97,8 @@ type RangeProofer interface {
 	GetRangeProofAtRoot(
 		ctx context.Context,
 		rootID ids.ID,
-		start,
-		end []byte,
+		start []byte,
+		end Maybe[[]byte],
 		maxLength int,
 	) (*RangeProof, error)
 
@@ -480,8 +480,8 @@ func (db *merkleDB) getProof(ctx context.Context, key []byte) (*Proof, error) {
 // [start, end].
 func (db *merkleDB) GetRangeProof(
 	ctx context.Context,
-	start,
-	end []byte,
+	start []byte,
+	end Maybe[[]byte],
 	maxLength int,
 ) (*RangeProof, error) {
 	db.commitLock.RLock()
@@ -495,8 +495,8 @@ func (db *merkleDB) GetRangeProof(
 func (db *merkleDB) GetRangeProofAtRoot(
 	ctx context.Context,
 	rootID ids.ID,
-	start,
-	end []byte,
+	start []byte,
+	end Maybe[[]byte],
 	maxLength int,
 ) (*RangeProof, error) {
 	db.commitLock.RLock()
@@ -509,8 +509,8 @@ func (db *merkleDB) GetRangeProofAtRoot(
 func (db *merkleDB) getRangeProofAtRoot(
 	ctx context.Context,
 	rootID ids.ID,
-	start,
-	end []byte,
+	start []byte,
+	end Maybe[[]byte],
 	maxLength int,
 ) (*RangeProof, error) {
 	if db.closed {
@@ -532,10 +532,10 @@ func (db *merkleDB) GetChangeProof(
 	startRootID ids.ID,
 	endRootID ids.ID,
 	start []byte,
-	end []byte,
+	end Maybe[[]byte],
 	maxLength int,
 ) (*ChangeProof, error) {
-	if len(end) > 0 && bytes.Compare(start, end) == 1 {
+	if end.HasValue() && bytes.Compare(start, end.Value()) == 1 {
 		return nil, ErrStartAfterEnd
 	}
 	if startRootID == endRootID {
@@ -578,20 +578,18 @@ func (db *merkleDB) GetChangeProof(
 		result.KeyChanges = append(result.KeyChanges, KeyChange{
 			Key: serializedKey,
 			// create a copy so edits of the []byte don't affect the db
-			Value: Clone(change.after),
+			Value: MaybeBind(change.after, slices.Clone[[]byte]),
 		})
 	}
 
-	largestKey := Nothing[[]byte]()
+	largestKey := end
 	if len(result.KeyChanges) > 0 {
 		largestKey = Some(result.KeyChanges[len(result.KeyChanges)-1].Key)
-	} else if len(end) > 0 {
-		largestKey = Some(end)
 	}
 
 	// Since we hold [db.commitlock] we must still have sufficient
 	// history to recreate the trie at [endRootID].
-	historicalView, err := db.getHistoricalViewForRange(endRootID, start, largestKey.Value())
+	historicalView, err := db.getHistoricalViewForRange(endRootID, start, largestKey)
 	if err != nil {
 		return nil, err
 	}
@@ -1006,14 +1004,12 @@ func (db *merkleDB) VerifyChangeProof(
 	// Find the greatest key in [proof.KeyChanges]
 	// Note that [proof.EndProof] is a proof for this key.
 	// [largestPath] is also used when we add children of proof nodes to [trie] below.
-	largestPath := Nothing[path]()
+	largestPath := MaybeBind(end, newPath)
 	if len(proof.KeyChanges) > 0 {
 		// If [proof] has key-value pairs, we should insert children
 		// greater than [end] to ancestors of the node containing [end]
 		// so that we get the expected root ID.
 		largestPath = Some(newPath(proof.KeyChanges[len(proof.KeyChanges)-1].Key))
-	} else if end.HasValue() {
-		largestPath = Some(newPath(end.Value()))
 	}
 
 	// Make sure the end proof, if given, is well-formed.
@@ -1169,7 +1165,7 @@ func (db *merkleDB) initializeRootIfNeeded() (ids.ID, error) {
 func (db *merkleDB) getHistoricalViewForRange(
 	rootID ids.ID,
 	start []byte,
-	end []byte,
+	end Maybe[[]byte],
 ) (*trieView, error) {
 	currentRootID := db.getMerkleRoot()
 

x/merkledb/db_test.go

@@ -259,7 +259,7 @@ func Test_MerkleDB_Commit_Proof_To_Empty_Trie(t *testing.T) {
 	require.NoError(batch.Put([]byte("key3"), []byte("3")))
 	require.NoError(batch.Write())
 
-	proof, err := db.GetRangeProof(context.Background(), []byte("key1"), []byte("key3"), 10)
+	proof, err := db.GetRangeProof(context.Background(), []byte("key1"), Some([]byte("key3")), 10)
 	require.NoError(err)
 
 	freshDB, err := getBasicDB()
@@ -289,7 +289,7 @@ func Test_MerkleDB_Commit_Proof_To_Filled_Trie(t *testing.T) {
 	require.NoError(batch.Put([]byte("key3"), []byte("3")))
 	require.NoError(batch.Write())
 
-	proof, err := db.GetRangeProof(context.Background(), []byte("key1"), []byte("key3"), 10)
+	proof, err := db.GetRangeProof(context.Background(), []byte("key1"), Some([]byte("key3")), 10)
 	require.NoError(err)
 
 	freshDB, err := getBasicDB()
@@ -768,12 +768,13 @@ func runRandDBTest(require *require.Assertions, r *rand.Rand, rt randTest) {
 			if len(pastRoots) > 0 {
 				root = pastRoots[r.Intn(len(pastRoots))]
 			}
-			rangeProof, err := db.GetRangeProofAtRoot(context.Background(), root, step.key, step.value, 100)
-			require.NoError(err)
 			end := Nothing[[]byte]()
 			if len(step.value) > 0 {
 				end = Some(step.value)
 			}
+
+			rangeProof, err := db.GetRangeProofAtRoot(context.Background(), root, step.key, end, 100)
+			require.NoError(err)
 			require.NoError(rangeProof.Verify(
 				context.Background(),
 				step.key,
@@ -787,18 +788,20 @@ func runRandDBTest(require *require.Assertions, r *rand.Rand, rt randTest) {
 			if len(pastRoots) > 1 {
 				root = pastRoots[r.Intn(len(pastRoots))]
 			}
-			changeProof, err := db.GetChangeProof(context.Background(), startRoot, root, step.key, step.value, 100)
+			end := Nothing[[]byte]()
+			if len(step.value) > 0 {
+				end = Some(step.value)
+			}
+
+			changeProof, err := db.GetChangeProof(context.Background(), startRoot, root, step.key, end, 100)
 			if startRoot == root {
 				require.ErrorIs(err, errSameRoot)
 				continue
 			}
 			require.NoError(err)
 			changeProofDB, err := getBasicDB()
 			require.NoError(err)
-			end := Nothing[[]byte]()
-			if len(step.value) > 0 {
-				end = Some(step.value)
-			}
+
 			require.NoError(changeProofDB.VerifyChangeProof(
 				context.Background(),
 				changeProof,

x/merkledb/history.go

@@ -78,7 +78,7 @@ func newTrieHistory(maxHistoryLookback int) *trieHistory {
 
 // Returns up to [maxLength] key-value pair changes with keys in [start, end] that
 // occurred between [startRoot] and [endRoot].
-func (th *trieHistory) getValueChanges(startRoot, endRoot ids.ID, start, end []byte, maxLength int) (*changeSummary, error) {
+func (th *trieHistory) getValueChanges(startRoot, endRoot ids.ID, start []byte, end Maybe[[]byte], maxLength int) (*changeSummary, error) {
 	if maxLength <= 0 {
 		return nil, fmt.Errorf("%w but was %d", ErrInvalidMaxLength, maxLength)
 	}
@@ -132,7 +132,7 @@ func (th *trieHistory) getValueChanges(startRoot, endRoot ids.ID, start, end []b
 	)
 
 	startPath := newPath(start)
-	endPath := newPath(end)
+	endPath := MaybeBind(end, newPath)
 
 	// For each element in the history in the range between [startRoot]'s
 	// last appearance (exclusive) and [endRoot]'s last appearance (inclusive),
@@ -158,7 +158,7 @@ func (th *trieHistory) getValueChanges(startRoot, endRoot ids.ID, start, end []b
 			for key, valueChange := range item.values {
 				// The key is outside the range [start, end].
 				if (len(startPath) > 0 && key.Compare(startPath) < 0) ||
-					(len(endPath) > 0 && key.Compare(endPath) > 0) {
+					(end.HasValue() && key.Compare(endPath.Value()) > 0) {
 					continue
 				}
 
@@ -198,7 +198,7 @@ func (th *trieHistory) getValueChanges(startRoot, endRoot ids.ID, start, end []b
 // for the keys in [start, end].
 // If [start] is nil, all keys are considered > [start].
 // If  [end] is nil, all keys are considered < [end].
-func (th *trieHistory) getChangesToGetToRoot(rootID ids.ID, start, end []byte) (*changeSummary, error) {
+func (th *trieHistory) getChangesToGetToRoot(rootID ids.ID, start []byte, end Maybe[[]byte]) (*changeSummary, error) {
 	// [lastRootChange] is the last change in the history resulting in [rootID].
 	lastRootChange, ok := th.lastChanges[rootID]
 	if !ok {
@@ -207,7 +207,7 @@ func (th *trieHistory) getChangesToGetToRoot(rootID ids.ID, start, end []byte) (
 
 	var (
 		startPath       = newPath(start)
-		endPath         = newPath(end)
+		endPath         = MaybeBind(end, newPath)
 		combinedChanges = newChangeSummary(defaultPreallocationSize)
 	)
 
@@ -227,7 +227,7 @@ func (th *trieHistory) getChangesToGetToRoot(rootID ids.ID, start, end []byte) (
 
 			for key, valueChange := range item.values {
 				if (len(startPath) == 0 || key.Compare(startPath) >= 0) &&
-					(len(endPath) == 0 || key.Compare(endPath) <= 0) {
+					(endPath.IsNothing() || key.Compare(endPath.Value()) <= 0) {
 					if existing, ok := combinedChanges.values[key]; ok {
 						existing.after = valueChange.before
 					} else {