fix(blooms): Fix findGaps when ownership goes to MaxUInt64 and that is covered by existing meta (#12558)

Author: salvacorts

pkg/bloomcompactor/controller.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"math"
 	"sort"
 	"sync"
 
@@ -735,7 +736,11 @@ func findGaps(ownershipRange v1.FingerprintBounds, metas []v1.FingerprintBounds)
 
 		searchRange := ownershipRange.Slice(leftBound, clippedMeta.Max)
 		// update the left bound for the next iteration
-		leftBound = min(clippedMeta.Max+1, ownershipRange.Max+1)
+		// We do the max to prevent the max bound to overflow from MaxUInt64 to 0
+		leftBound = min(
+			max(clippedMeta.Max+1, clippedMeta.Max),
+			max(ownershipRange.Max+1, ownershipRange.Max),
+		)
 
 		// since we've already ensured that the meta is within the ownership range,
 		// we know the xor will be of length zero (when the meta is equal to the ownership range)
@@ -750,8 +755,11 @@ func findGaps(ownershipRange v1.FingerprintBounds, metas []v1.FingerprintBounds)
 		gaps = append(gaps, xors[0])
 	}
 
-	if leftBound <= ownershipRange.Max {
-		// There is a gap between the last meta and the end of the ownership range.
+	// If the leftBound is less than the ownership range max, and it's smaller than MaxUInt64,
+	// There is a gap between the last meta and the end of the ownership range.
+	// Note: we check `leftBound < math.MaxUint64` since in the loop above we clamp the
+	// leftBound to MaxUint64 to prevent an overflow to 0: `max(clippedMeta.Max+1, clippedMeta.Max)`
+	if leftBound < math.MaxUint64 && leftBound <= ownershipRange.Max {
 		gaps = append(gaps, v1.NewBounds(leftBound, ownershipRange.Max))
 	}
 

pkg/bloomcompactor/controller_test.go

@@ -2,6 +2,7 @@ package bloomcompactor
 
 import (
 	"fmt"
+	"math"
 	"testing"
 	"time"
 
@@ -103,6 +104,27 @@ func Test_findGaps(t *testing.T) {
 				v1.NewBounds(6, 7),
 			},
 		},
+		{
+			desc:           "full ownership range with single meta",
+			err:            false,
+			exp:            nil,
+			ownershipRange: v1.NewBounds(0, math.MaxUint64),
+			metas: []v1.FingerprintBounds{
+				v1.NewBounds(0, math.MaxUint64),
+			},
+		},
+		{
+			desc:           "full ownership range with multiple metas",
+			err:            false,
+			exp:            nil,
+			ownershipRange: v1.NewBounds(0, math.MaxUint64),
+			// Three metas covering the whole 0 - MaxUint64
+			metas: []v1.FingerprintBounds{
+				v1.NewBounds(0, math.MaxUint64/3),
+				v1.NewBounds(math.MaxUint64/3+1, math.MaxUint64/2),
+				v1.NewBounds(math.MaxUint64/2+1, math.MaxUint64),
+			},
+		},
 	} {
 		t.Run(tc.desc, func(t *testing.T) {
 			gaps, err := findGaps(tc.ownershipRange, tc.metas)