From 9fc5e014191f41d4b5dbd1080b56841da732d913 Mon Sep 17 00:00:00 2001
From: LeSingh1 <sshaurya914@gmail.com>
Date: Fri, 12 Jun 2026 00:09:48 -0700
Subject: [PATCH] fix(table): clamp cursor to 0 when SetRows is called with
 empty slice

When SetRows was called with an empty rows slice, len(m.rows)-1 evaluated
to -1, causing cursor to be set to -1. Subsequent calls to Cursor() would
return -1, which is out of bounds and breaks callers that expect a valid
index.

The fix guards for the empty case and resets cursor to 0, consistent with
the initial state of a new table. The existing shrink-to-fewer-rows guard
is preserved for the non-empty case.

Adds a regression test covering both the empty-rows reset and the
previously-tested shrink case.
---
 table/cursor_shrink_test.go | 42 +++++++++++++++++++++++++++++++++++++
 table/table.go              |  4 +++-
 2 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 table/cursor_shrink_test.go

diff --git a/table/cursor_shrink_test.go b/table/cursor_shrink_test.go
new file mode 100644
index 000000000..62394327f
--- /dev/null
+++ b/table/cursor_shrink_test.go
@@ -0,0 +1,42 @@
+package table
+
+import (
+	"testing"
+)
+
+func TestSetRows_CursorClampsToZeroOnEmpty(t *testing.T) {
+	cols := []Column{{Title: "Name", Width: 10}}
+	rows := []Row{{"a"}, {"b"}, {"c"}}
+	tbl := New(WithColumns(cols), WithRows(rows), WithHeight(5))
+
+	// Move to last row
+	tbl.GotoBottom()
+	if tbl.Cursor() != 2 {
+		t.Fatalf("expected cursor at 2, got %d", tbl.Cursor())
+	}
+
+	// Replace with empty rows
+	tbl.SetRows([]Row{})
+
+	got := tbl.Cursor()
+	if got < 0 {
+		t.Fatalf("SetRows(empty): Cursor() = %d, want >= 0 (got negative cursor on empty table)", got)
+	}
+}
+
+func TestSetRows_CursorClampsOnShrink(t *testing.T) {
+	cols := []Column{{Title: "Name", Width: 10}}
+	rows := []Row{{"a"}, {"b"}, {"c"}}
+	tbl := New(WithColumns(cols), WithRows(rows), WithHeight(5))
+
+	// Move to last row (index 2)
+	tbl.GotoBottom()
+
+	// Shrink to 1 row
+	tbl.SetRows([]Row{{"x"}})
+
+	got := tbl.Cursor()
+	if got != 0 {
+		t.Fatalf("SetRows(fewer rows): Cursor() = %d, want 0", got)
+	}
+}
diff --git a/table/table.go b/table/table.go
index 39f9a4003..e75910618 100644
--- a/table/table.go
+++ b/table/table.go
@@ -306,7 +306,9 @@ func (m Model) Columns() []Column {
 func (m *Model) SetRows(r []Row) {
 	m.rows = r
 
-	if m.cursor > len(m.rows)-1 {
+	if len(m.rows) == 0 {
+		m.cursor = 0
+	} else if m.cursor > len(m.rows)-1 {
 		m.cursor = len(m.rows) - 1
 	}