op-program/host: have prefetcher use new beacon API (not blob_sidecars)

op-program/host/prefetcher/prefetcher.go

@@ -54,7 +54,6 @@ type L1Source interface {
 }
 
 type L1BlobSource interface {
-	GetBlobSidecars(ctx context.Context, ref eth.L1BlockRef, hashes []eth.IndexedBlobHash) ([]*eth.BlobSidecar, error)
 	GetBlobs(ctx context.Context, ref eth.L1BlockRef, hashes []eth.IndexedBlobHash) ([]*eth.Blob, error)
 }
 
@@ -325,35 +324,38 @@ func (p *Prefetcher) prefetch(ctx context.Context, hint string) error {
 		blobHashIndex := binary.BigEndian.Uint64(hintBytes[32:40])
 		refTimestamp := binary.BigEndian.Uint64(hintBytes[40:48])
 
-		// Fetch the blob sidecar for the indexed blob hash passed in the hint.
+		// Fetch the blob for the indexed blob hash passed in the hint.
 		indexedBlobHash := eth.IndexedBlobHash{
 			Hash:  blobVersionHash,
 			Index: blobHashIndex,
 		}
-		// We pass an `eth.L1BlockRef`, but `GetBlobSidecars` only uses the timestamp, which we received in the hint.
-		sidecars, err := p.l1BlobFetcher.GetBlobSidecars(ctx, eth.L1BlockRef{Time: refTimestamp}, []eth.IndexedBlobHash{indexedBlobHash})
-		if err != nil || len(sidecars) != 1 {
-			return fmt.Errorf("failed to fetch blob sidecars for %s %d: %w", blobVersionHash, blobHashIndex, err)
+		// We pass an `eth.L1BlockRef`, but `GetBlobs` only uses the timestamp, which we received in the hint.
+		blobs, err := p.l1BlobFetcher.GetBlobs(ctx, eth.L1BlockRef{Time: refTimestamp}, []eth.IndexedBlobHash{indexedBlobHash})
+		if err != nil || len(blobs) != 1 {
+			return fmt.Errorf("failed to fetch blobs for %s %d: %w", blobVersionHash, blobHashIndex, err)
+		}
+		blob := blobs[0]
+		kzgCommitment, err := blob.ComputeKZGCommitment()
+		if err != nil {
+			return fmt.Errorf("failed to compute KZG commitment for blob: %w", err)
 		}
-		sidecar := sidecars[0]
-
 		// Put the preimage for the versioned hash into the kv store
-		if err = p.kvStore.Put(preimage.Sha256Key(blobVersionHash).PreimageKey(), sidecar.KZGCommitment[:]); err != nil {
+		if err = p.kvStore.Put(preimage.Sha256Key(blobVersionHash).PreimageKey(), kzgCommitment[:]); err != nil {
 			return err
 		}
 
 		// Put all of the blob's field elements into the kv store. There should be 4096. The preimage oracle key for
 		// each field element is the keccak256 hash of `abi.encodePacked(sidecar.KZGCommitment, RootsOfUnity[i])`
 		blobKey := make([]byte, 80)
-		copy(blobKey[:48], sidecar.KZGCommitment[:])
+		copy(blobKey[:48], kzgCommitment[:])
 		for i := 0; i < params.BlobTxFieldElementsPerBlob; i++ {
 			rootOfUnity := l1.RootsOfUnity[i].Bytes()
 			copy(blobKey[48:], rootOfUnity[:])
 			blobKeyHash := crypto.Keccak256Hash(blobKey)
 			if err := p.kvStore.Put(preimage.Keccak256Key(blobKeyHash).PreimageKey(), blobKey); err != nil {
 				return err
 			}
-			if err = p.kvStore.Put(preimage.BlobKey(blobKeyHash).PreimageKey(), sidecar.Blob[i<<5:(i+1)<<5]); err != nil {
+			if err = p.kvStore.Put(preimage.BlobKey(blobKeyHash).PreimageKey(), blob[i<<5:(i+1)<<5]); err != nil {
 				return err
 			}
 		}

op-program/host/prefetcher/prefetcher_test.go

@@ -204,11 +204,10 @@ func TestFetchL1Blob(t *testing.T) {
 		prefetcher, _, blobFetcher, _, _ := createPrefetcher(t)
 
 		oracle := l1.NewPreimageOracle(asOracleFn(t, prefetcher), asHinter(t, prefetcher))
-		blobFetcher.ExpectOnGetBlobSidecars(
+		blobFetcher.ExpectOnGetBlobs(
 			context.Background(),
 			l1Ref,
 			[]eth.IndexedBlobHash{blobHash},
-			(eth.Bytes48)(commitment),
 			[]*eth.Blob{&blob},
 			nil,
 		)

op-program/host/prefetcher/retry.go

@@ -75,16 +75,6 @@ func NewRetryingL1BlobSource(logger log.Logger, source L1BlobSource) *RetryingL1
 	}
 }
 
-func (s *RetryingL1BlobSource) GetBlobSidecars(ctx context.Context, ref eth.L1BlockRef, hashes []eth.IndexedBlobHash) ([]*eth.BlobSidecar, error) {
-	return retry.Do(ctx, maxAttempts, s.strategy, func() ([]*eth.BlobSidecar, error) {
-		sidecars, err := s.source.GetBlobSidecars(ctx, ref, hashes)
-		if err != nil {
-			s.logger.Warn("Failed to retrieve blob sidecars", "ref", ref, "err", err)
-		}
-		return sidecars, err
-	})
-}
-
 func (s *RetryingL1BlobSource) GetBlobs(ctx context.Context, ref eth.L1BlockRef, hashes []eth.IndexedBlobHash) ([]*eth.Blob, error) {
 	return retry.Do(ctx, maxAttempts, s.strategy, func() ([]*eth.Blob, error) {
 		blobs, err := s.source.GetBlobs(ctx, ref, hashes)

op-program/host/prefetcher/retry_test.go

@@ -163,55 +163,6 @@ func TestRetryingL1BlobSource(t *testing.T) {
 		require.Equal(t, len(result), 1)
 		require.Equal(t, blob[:], result[0][:])
 	})
-
-	t.Run("GetBlobSidecars Success", func(t *testing.T) {
-		source, mock := createL1BlobSource(t)
-		defer mock.AssertExpectations(t)
-		mock.ExpectOnGetBlobSidecars(
-			ctx,
-			l1BlockRef,
-			[]eth.IndexedBlobHash{blobHash},
-			(eth.Bytes48)(commitment),
-			[]*eth.Blob{(*eth.Blob)(&blob)},
-			nil,
-		)
-
-		result, err := source.GetBlobSidecars(ctx, l1BlockRef, []eth.IndexedBlobHash{blobHash})
-		require.NoError(t, err)
-		require.Equal(t, len(result), 1)
-		require.Equal(t, blob[:], result[0].Blob[:])
-		require.Equal(t, blobHash.Index, uint64(result[0].Index))
-		require.Equal(t, (eth.Bytes48)(commitment), result[0].KZGCommitment)
-	})
-
-	t.Run("GetBlobSidecars Error", func(t *testing.T) {
-		source, mock := createL1BlobSource(t)
-		defer mock.AssertExpectations(t)
-		expectedErr := errors.New("boom")
-		mock.ExpectOnGetBlobSidecars(
-			ctx,
-			l1BlockRef,
-			[]eth.IndexedBlobHash{blobHash},
-			(eth.Bytes48)(commitment),
-			[]*eth.Blob{(*eth.Blob)(&blob)},
-			expectedErr,
-		)
-		mock.ExpectOnGetBlobSidecars(
-			ctx,
-			l1BlockRef,
-			[]eth.IndexedBlobHash{blobHash},
-			(eth.Bytes48)(commitment),
-			[]*eth.Blob{(*eth.Blob)(&blob)},
-			nil,
-		)
-
-		result, err := source.GetBlobSidecars(ctx, l1BlockRef, []eth.IndexedBlobHash{blobHash})
-		require.NoError(t, err)
-		require.Equal(t, len(result), 1)
-		require.Equal(t, blob[:], result[0].Blob[:])
-		require.Equal(t, blobHash.Index, uint64(result[0].Index))
-		require.Equal(t, (eth.Bytes48)(commitment), result[0].KZGCommitment)
-	})
 }
 
 func createL1BlobSource(t *testing.T) (*RetryingL1BlobSource, *testutils.MockBlobsFetcher) {