From 516ad171d2c05b9d52d50c173e41a646941f8c6d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Magiera?= <magik6k@gmail.com>
Date: Wed, 12 Oct 2022 10:03:22 +0200
Subject: [PATCH] fix: bstore: Handle codecs correctly in membstore Get

---
 blockstore/mem.go      |  3 +++
 blockstore/mem_test.go | 45 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 blockstore/mem_test.go

diff --git a/blockstore/mem.go b/blockstore/mem.go
index 15708dcd4..7cfefafd7 100644
--- a/blockstore/mem.go
+++ b/blockstore/mem.go
@@ -47,6 +47,9 @@ func (m MemBlockstore) Get(ctx context.Context, k cid.Cid) (blocks.Block, error)
 	if !ok {
 		return nil, ipld.ErrNotFound{Cid: k}
 	}
+	if b.Cid().Prefix().Codec != k.Prefix().Codec {
+		return blocks.NewBlockWithCid(b.RawData(), k)
+	}
 	return b, nil
 }
 
diff --git a/blockstore/mem_test.go b/blockstore/mem_test.go
new file mode 100644
index 000000000..4d4a77624
--- /dev/null
+++ b/blockstore/mem_test.go
@@ -0,0 +1,45 @@
+package blockstore
+
+import (
+	"context"
+	"testing"
+
+	blocks "github.com/ipfs/go-block-format"
+	"github.com/ipfs/go-cid"
+	mh "github.com/multiformats/go-multihash"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMemGetCodec(t *testing.T) {
+	ctx := context.Background()
+	bs := NewMemory()
+
+	cborArr := []byte{0x82, 1, 2}
+
+	h, err := mh.Sum(cborArr, mh.SHA2_256, -1)
+	require.NoError(t, err)
+
+	rawCid := cid.NewCidV1(cid.Raw, h)
+	rawBlk, err := blocks.NewBlockWithCid(cborArr, rawCid)
+	require.NoError(t, err)
+
+	err = bs.Put(ctx, rawBlk)
+	require.NoError(t, err)
+
+	cborCid := cid.NewCidV1(cid.DagCBOR, h)
+
+	cborBlk, err := bs.Get(ctx, cborCid)
+	require.NoError(t, err)
+
+	require.Equal(t, cborCid.Prefix(), cborBlk.Cid().Prefix())
+	require.EqualValues(t, cborArr, cborBlk.RawData())
+
+	// was allocated
+	require.NotEqual(t, cborBlk, rawBlk)
+
+	gotRawBlk, err := bs.Get(ctx, rawCid)
+	require.NoError(t, err)
+
+	// not allocated
+	require.Equal(t, rawBlk, gotRawBlk)
+}