Do not return an error when block is unavailable due to expiry

fvm/environment/block_info.go

@@ -143,7 +143,7 @@ func (info *blockInfo) GetBlockAtHeight(
 	}
 
 	if height+uint64(flow.DefaultTransactionExpiry) < info.blockHeader.Height {
-		return runtime.Block{}, false, errors.NewBlockHeightOutOfRangeError(height)
+		return runtime.Block{}, false, nil
 	}
 
 	header, err := info.blocks.ByHeightFrom(height, info.blockHeader)

fvm/environment/block_info_test.go

@@ -0,0 +1,69 @@
+package environment_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/onflow/flow-go/cmd/util/ledger/util"
+	"github.com/onflow/flow-go/fvm/environment"
+	"github.com/onflow/flow-go/fvm/tracing"
+	"github.com/onflow/flow-go/model/flow"
+	storageErr "github.com/onflow/flow-go/storage"
+	"github.com/onflow/flow-go/utils/unittest"
+)
+
+func TestBlockInfo(t *testing.T) {
+	tracer := tracing.NewMockTracerSpan()
+	meter := &util.NopMeter{}
+	blocks := &mockBlocks{
+		blocks: make(map[uint64]*flow.Header),
+	}
+	height := uint64(flow.DefaultTransactionExpiry)
+	header := unittest.BlockHeaderWithHeight(height)
+
+	bi := environment.NewBlockInfo(tracer, meter, header, blocks)
+
+	// verify the current block exists
+	blocks.Add(header)
+	b, exists, err := bi.GetBlockAtHeight(height)
+	require.NoError(t, err)
+	require.True(t, exists)
+	require.Equal(t, header.Height, b.Height)
+
+	// verify blocks that do not exist
+	b, exists, err = bi.GetBlockAtHeight(height + 1)
+	require.NoError(t, err)
+	require.False(t, exists)
+
+	// verify that the block at the height before the lowest accepted height exists
+	lowestAcceptedHeight := height - flow.DefaultTransactionExpiry
+	lowestHeader := unittest.BlockHeaderWithHeight(lowestAcceptedHeight)
+	blocks.Add(lowestHeader)
+	b, exists, err = bi.GetBlockAtHeight(lowestAcceptedHeight)
+	require.NoError(t, err)
+	require.True(t, exists)
+	require.Equal(t, lowestHeader.Height, b.Height)
+
+	// verify that the block at the height before the lowest accepted height does not exist
+	_, exists, err = bi.GetBlockAtHeight(lowestAcceptedHeight - 1)
+	require.NoError(t, err)
+	require.False(t, exists)
+}
+
+type mockBlocks struct {
+	blocks map[uint64]*flow.Header
+}
+
+func (m *mockBlocks) ByHeightFrom(height uint64, header *flow.Header) (*flow.Header, error) {
+	h, ok := m.blocks[height]
+	if !ok {
+		return nil, fmt.Errorf("block does not exist: %w", storageErr.ErrNotFound)
+	}
+	return h, nil
+}
+
+func (m *mockBlocks) Add(h *flow.Header) {
+	m.blocks[h.Height] = h
+}

utils/unittest/fixtures.go

@@ -532,6 +532,10 @@ func BlockHeaderWithParentFixture(parent *flow.Header) *flow.Header {
 	}
 }
 
+func BlockHeaderWithHeight(height uint64) *flow.Header {
+	return BlockHeaderFixture(WithHeaderHeight(height))
+}
+
 func BlockHeaderWithParentWithSoRFixture(parent *flow.Header, source []byte) *flow.Header {
 	height := parent.Height + 1
 	view := parent.View + 1 + uint64(rand.Intn(10)) // Intn returns [0, n)