Merge pull request #686 from peco/fix-error-handling-minor

tweak handling

query.go

@@ -72,6 +72,9 @@ func (q *Query) RuneSlice() []rune {
 func (q *Query) RuneAt(where int) rune {
 	q.mutex.Lock()
 	defer q.mutex.Unlock()
+	if where < 0 || where >= len(q.query) {
+		return 0
+	}
 	return q.query[where]
 }
 

query_test.go

@@ -152,6 +152,25 @@ func TestQueryRuneAtUnicode(t *testing.T) {
 	require.Equal(t, 'う', q.RuneAt(2))
 }
 
+func TestQueryRuneAtOutOfBounds(t *testing.T) {
+	t.Parallel()
+	var q Query
+	q.Set("hello")
+
+	// Out-of-bounds index returns zero rune without panicking
+	require.Equal(t, rune(0), q.RuneAt(5))
+	require.Equal(t, rune(0), q.RuneAt(100))
+
+	// Negative index returns zero rune without panicking
+	require.Equal(t, rune(0), q.RuneAt(-1))
+	require.Equal(t, rune(0), q.RuneAt(-100))
+
+	// Empty query: any index returns zero rune
+	var empty Query
+	require.Equal(t, rune(0), empty.RuneAt(0))
+	require.Equal(t, rune(0), empty.RuneAt(-1))
+}
+
 func TestQueryInsertAt(t *testing.T) {
 	t.Parallel()
 	tests := []struct {

source.go

@@ -106,7 +106,7 @@ func (s *Source) Setup(ctx context.Context, state *Peco) {
 			}
 			if closer, ok := s.in.(io.Closer); ok {
 				s.inClosed = true
-				closer.Close()
+				_ = closer.Close()
 			}
 		}()