Return an empty slice from GetSetBits for nil/empty buffers

Author: danielway-wk

bitarray/bitarray.go

@@ -139,6 +139,10 @@ func getSetBitsInBlocks(
 	buffer []uint64,
 ) []uint64 {
 	bufferCapacity := cap(buffer)
+	if bufferCapacity == 0 {
+		return buffer[:0]
+	}
+
 	results := buffer[:bufferCapacity]
 	resultSize := 0
 

bitarray/bitarray_test.go

@@ -230,6 +230,9 @@ func TestGetSetBits(t *testing.T) {
 	require.NoError(t, ba.SetBit(200))
 	require.NoError(t, ba.SetBit(1000))
 
+	assert.Equal(t, []uint64(nil), ba.GetSetBits(0, nil))
+	assert.Equal(t, []uint64{}, ba.GetSetBits(0, []uint64{}))
+
 	assert.Equal(t, []uint64{1, 4, 8, 63, 64}, ba.GetSetBits(0, buf))
 	assert.Equal(t, []uint64{63, 64, 200, 1000}, ba.GetSetBits(10, buf))
 	assert.Equal(t, []uint64{63, 64, 200, 1000}, ba.GetSetBits(63, buf))

bitarray/sparse_bitarray_test.go

@@ -89,6 +89,9 @@ func TestGetSetCompressedBits(t *testing.T) {
 	require.NoError(t, ba.SetBit(200))
 	require.NoError(t, ba.SetBit(1000))
 
+	assert.Equal(t, []uint64(nil), ba.GetSetBits(0, nil))
+	assert.Equal(t, []uint64{}, ba.GetSetBits(0, []uint64{}))
+
 	assert.Equal(t, []uint64{1, 4, 8, 63, 64}, ba.GetSetBits(0, buf))
 	assert.Equal(t, []uint64{63, 64, 200, 1000}, ba.GetSetBits(10, buf))
 	assert.Equal(t, []uint64{63, 64, 200, 1000}, ba.GetSetBits(63, buf))