From 91e66999fb7a7847a4a340f773471546aa6823c4 Mon Sep 17 00:00:00 2001
From: Zihan Dai <99155080+PDGGK@users.noreply.github.com>
Date: Wed, 22 Jul 2026 04:03:15 +1000
Subject: [PATCH] Fix off-by-one bounds check in Tablet.SetValueAt/GetValueAt

The columnIndex/rowIndex guards used `> len(measurementSchemas)` and
`> maxRowNumber`, which let the exact boundary index (columnIndex ==
len, rowIndex == maxRowNumber) escape the check. Since the schema and
value slices have exactly those lengths, the boundary index then hit a
runtime "index out of range" panic instead of the intended "illegal
argument" error that both methods are meant to return.

Change all four guards to `>=`, and add exact-boundary regression cases
to TestTablet_SetValueAt / TestTablet_GetValueAt.

Signed-off-by: Zihan Dai <99155080+PDGGK@users.noreply.github.com>
---
 client/tablet.go      |  8 ++++----
 client/tablet_test.go | 30 ++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/client/tablet.go b/client/tablet.go
index e161ddc..04d828b 100644
--- a/client/tablet.go
+++ b/client/tablet.go
@@ -110,11 +110,11 @@ func (t *Tablet) SetTimestamp(timestamp int64, rowIndex int) {
 
 func (t *Tablet) SetValueAt(value interface{}, columnIndex, rowIndex int) error {
 
-	if columnIndex < 0 || columnIndex > len(t.measurementSchemas) {
+	if columnIndex < 0 || columnIndex >= len(t.measurementSchemas) {
 		return fmt.Errorf("illegal argument columnIndex %d", columnIndex)
 	}
 
-	if rowIndex < 0 || rowIndex > t.maxRowNumber {
+	if rowIndex < 0 || rowIndex >= t.maxRowNumber {
 		return fmt.Errorf("illegal argument rowIndex %d", rowIndex)
 	}
 
@@ -221,11 +221,11 @@ func (t *Tablet) GetMaxRowNumber() int {
 }
 
 func (t *Tablet) GetValueAt(columnIndex, rowIndex int) (interface{}, error) {
-	if columnIndex < 0 || columnIndex > len(t.measurementSchemas) {
+	if columnIndex < 0 || columnIndex >= len(t.measurementSchemas) {
 		return nil, fmt.Errorf("illegal argument columnIndex %d", columnIndex)
 	}
 
-	if rowIndex < 0 || rowIndex > t.maxRowNumber {
+	if rowIndex < 0 || rowIndex >= t.maxRowNumber {
 		return nil, fmt.Errorf("illegal argument rowIndex %d", rowIndex)
 	}
 
diff --git a/client/tablet_test.go b/client/tablet_test.go
index b19f34a..cd01d72 100644
--- a/client/tablet_test.go
+++ b/client/tablet_test.go
@@ -224,6 +224,22 @@ func TestTablet_SetValueAt(t *testing.T) {
 				rowIndex:    0,
 			},
 			wantErr: true,
+		}, {
+			name: "columnIndex-out-of-range-boundary",
+			args: args{
+				value:       0,
+				columnIndex: 10,
+				rowIndex:    0,
+			},
+			wantErr: true,
+		}, {
+			name: "rowIndex-out-of-range-boundary",
+			args: args{
+				value:       0,
+				columnIndex: 0,
+				rowIndex:    1,
+			},
+			wantErr: true,
 		}, {
 			name: "restart_count",
 			args: args{
@@ -410,6 +426,20 @@ func TestTablet_GetValueAt(t *testing.T) {
 			},
 			want:    int64(1608268702780),
 			wantErr: false,
+		}, {
+			name: "columnIndex-out-of-range-boundary",
+			args: args{
+				columnIndex: 10,
+				rowIndex:    0,
+			},
+			wantErr: true,
+		}, {
+			name: "rowIndex-out-of-range-boundary",
+			args: args{
+				columnIndex: 0,
+				rowIndex:    1,
+			},
+			wantErr: true,
 		},
 	}
 	if tablet, err := createTablet(1); err == nil {