From 7e21caae6e2b675985249312395acdb3b312a200 Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Fri, 5 Apr 2024 14:49:34 +0300
Subject: [PATCH 01/10] Changed error type

---
 engine/access/rpc/backend/backend_stream_blocks.go | 4 ++--
 engine/access/state_stream/backend/backend.go      | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/engine/access/rpc/backend/backend_stream_blocks.go b/engine/access/rpc/backend/backend_stream_blocks.go
index a2ce866137b..1082d0b0357 100644
--- a/engine/access/rpc/backend/backend_stream_blocks.go
+++ b/engine/access/rpc/backend/backend_stream_blocks.go
@@ -339,7 +339,7 @@ func (b *backendSubscribeBlocks) getBlock(height uint64, expectedBlockStatus flo
 
 // validateHeight checks if the given block height is valid and available based on the expected block status.
 // Expected errors during normal operation:
-// - storage.ErrNotFound: block for the given block height is not available.
+// - subscription.ErrBlockNotReady when unable to retrieve the block by height
 func (b *backendSubscribeBlocks) validateHeight(height uint64, expectedBlockStatus flow.BlockStatus) error {
 	highestHeight, err := b.blockTracker.GetHighestHeight(expectedBlockStatus)
 	if err != nil {
@@ -350,7 +350,7 @@ func (b *backendSubscribeBlocks) validateHeight(height uint64, expectedBlockStat
 	// note: it's possible for the data to exist in the data store before the notification is
 	// received. this ensures a consistent view is available to all streams.
 	if height > highestHeight {
-		return fmt.Errorf("block %d is not available yet: %w", height, storage.ErrNotFound)
+		return fmt.Errorf("block %d is not available yet: %w", height, subscription.ErrBlockNotReady)
 	}
 
 	return nil
diff --git a/engine/access/state_stream/backend/backend.go b/engine/access/state_stream/backend/backend.go
index d82daad8a7f..a49dd9bd23f 100644
--- a/engine/access/state_stream/backend/backend.go
+++ b/engine/access/state_stream/backend/backend.go
@@ -156,14 +156,14 @@ func New(
 
 // getExecutionData returns the execution data for the given block height.
 // Expected errors during normal operation:
-// - storage.ErrNotFound or execution_data.BlobNotFoundError: execution data for the given block height is not available.
+// - subscription.ErrBlockNotReady or execution_data.BlobNotFoundError: execution data for the given block height is not available.
 func (b *StateStreamBackend) getExecutionData(ctx context.Context, height uint64) (*execution_data.BlockExecutionDataEntity, error) {
 	highestHeight := b.ExecutionDataTracker.GetHighestHeight()
 	// fail early if no notification has been received for the given block height.
 	// note: it's possible for the data to exist in the data store before the notification is
 	// received. this ensures a consistent view is available to all streams.
 	if height > highestHeight {
-		return nil, fmt.Errorf("execution data for block %d is not available yet: %w", height, storage.ErrNotFound)
+		return nil, fmt.Errorf("execution data for block %d is not available yet: %w", height, subscription.ErrBlockNotReady)
 	}
 
 	execData, err := b.execDataCache.ByHeight(ctx, height)

From 05f9293bb5381252bc2d1121dfcea85453ac2fc1 Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Fri, 5 Apr 2024 16:40:36 +0300
Subject: [PATCH 02/10] Added dot

---
 engine/access/rpc/backend/backend_stream_blocks.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/engine/access/rpc/backend/backend_stream_blocks.go b/engine/access/rpc/backend/backend_stream_blocks.go
index 1082d0b0357..3d349221fdd 100644
--- a/engine/access/rpc/backend/backend_stream_blocks.go
+++ b/engine/access/rpc/backend/backend_stream_blocks.go
@@ -339,7 +339,7 @@ func (b *backendSubscribeBlocks) getBlock(height uint64, expectedBlockStatus flo
 
 // validateHeight checks if the given block height is valid and available based on the expected block status.
 // Expected errors during normal operation:
-// - subscription.ErrBlockNotReady when unable to retrieve the block by height
+// - subscription.ErrBlockNotReady when unable to retrieve the block by height.
 func (b *backendSubscribeBlocks) validateHeight(height uint64, expectedBlockStatus flow.BlockStatus) error {
 	highestHeight, err := b.blockTracker.GetHighestHeight(expectedBlockStatus)
 	if err != nil {

From 3aca83a0c9f7bca4508bbe790ed188d9aa12cfa7 Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Wed, 10 Apr 2024 16:01:45 +0300
Subject: [PATCH 03/10] Added error check in getExecutionData function

---
 engine/access/state_stream/backend/backend.go | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/engine/access/state_stream/backend/backend.go b/engine/access/state_stream/backend/backend.go
index 9bebc0cc922..4fd3b33e6ce 100644
--- a/engine/access/state_stream/backend/backend.go
+++ b/engine/access/state_stream/backend/backend.go
@@ -156,7 +156,15 @@ func (b *StateStreamBackend) getExecutionData(ctx context.Context, height uint64
 
 	execData, err := b.execDataCache.ByHeight(ctx, height)
 	if err != nil {
-		return nil, fmt.Errorf("could not get execution data for block %d: %w", height, err)
+		var errMsg error
+		if errors.Is(err, storage.ErrNotFound) ||
+			errors.Is(err, storage.ErrHeightNotIndexed) ||
+			execution_data.IsBlobNotFoundError(err) {
+			errMsg = subscription.ErrBlockNotReady
+		} else {
+			errMsg = err
+		}
+		return nil, fmt.Errorf("could not get execution data for block %d: %w", height, errMsg)
 	}
 
 	return execData, nil

From 8290b0c00805df80c57f953c940f6e1083c76b9d Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Thu, 11 Apr 2024 13:56:18 +0300
Subject: [PATCH 04/10] Changed error for other streaming endpoints

---
 engine/access/rpc/backend/backend_stream_blocks.go    |  7 +++++++
 engine/access/state_stream/backend/backend.go         |  3 +--
 .../state_stream/backend/backend_account_statuses.go  |  7 +++++++
 engine/access/state_stream/backend/backend_events.go  | 11 +++++++++--
 .../state_stream/backend/backend_executiondata.go     |  7 +++++--
 5 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/engine/access/rpc/backend/backend_stream_blocks.go b/engine/access/rpc/backend/backend_stream_blocks.go
index 842bddd9d05..c31afb7f7fc 100644
--- a/engine/access/rpc/backend/backend_stream_blocks.go
+++ b/engine/access/rpc/backend/backend_stream_blocks.go
@@ -2,6 +2,7 @@ package backend
 
 import (
 	"context"
+	"errors"
 	"fmt"
 
 	"github.com/rs/zerolog"
@@ -293,6 +294,9 @@ func (b *backendSubscribeBlocks) getBlockHeader(height uint64, expectedBlockStat
 	// since we are querying a finalized or sealed block header, we can use the height index and save an ID computation
 	header, err := b.headers.ByHeight(height)
 	if err != nil {
+		if errors.Is(err, storage.ErrNotFound) {
+			return nil, fmt.Errorf("failed to retrieve block ID for height %d: %w", height, subscription.ErrBlockNotReady)
+		}
 		return nil, err
 	}
 
@@ -311,6 +315,9 @@ func (b *backendSubscribeBlocks) getBlock(height uint64, expectedBlockStatus flo
 	// since we are querying a finalized or sealed block, we can use the height index and save an ID computation
 	block, err := b.blocks.ByHeight(height)
 	if err != nil {
+		if errors.Is(err, storage.ErrNotFound) {
+			return nil, fmt.Errorf("failed to retrieve block ID for height %d: %w", height, subscription.ErrBlockNotReady)
+		}
 		return nil, err
 	}
 
diff --git a/engine/access/state_stream/backend/backend.go b/engine/access/state_stream/backend/backend.go
index 4fd3b33e6ce..13ec8bd33ce 100644
--- a/engine/access/state_stream/backend/backend.go
+++ b/engine/access/state_stream/backend/backend.go
@@ -144,7 +144,7 @@ func New(
 
 // getExecutionData returns the execution data for the given block height.
 // Expected errors during normal operation:
-// - subscription.ErrBlockNotReady or execution_data.BlobNotFoundError: execution data for the given block height is not available.
+// - subscription.ErrBlockNotReady: execution data for the given block height is not available.
 func (b *StateStreamBackend) getExecutionData(ctx context.Context, height uint64) (*execution_data.BlockExecutionDataEntity, error) {
 	highestHeight := b.ExecutionDataTracker.GetHighestHeight()
 	// fail early if no notification has been received for the given block height.
@@ -158,7 +158,6 @@ func (b *StateStreamBackend) getExecutionData(ctx context.Context, height uint64
 	if err != nil {
 		var errMsg error
 		if errors.Is(err, storage.ErrNotFound) ||
-			errors.Is(err, storage.ErrHeightNotIndexed) ||
 			execution_data.IsBlobNotFoundError(err) {
 			errMsg = subscription.ErrBlockNotReady
 		} else {
diff --git a/engine/access/state_stream/backend/backend_account_statuses.go b/engine/access/state_stream/backend/backend_account_statuses.go
index 3e408f02f96..4accbe26bdf 100644
--- a/engine/access/state_stream/backend/backend_account_statuses.go
+++ b/engine/access/state_stream/backend/backend_account_statuses.go
@@ -2,12 +2,15 @@ package backend
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/rs/zerolog"
 
 	"github.com/onflow/flow-go/engine/access/state_stream"
 	"github.com/onflow/flow-go/engine/access/subscription"
+	"github.com/onflow/flow-go/fvm/errors"
 	"github.com/onflow/flow-go/model/flow"
+	"github.com/onflow/flow-go/storage"
 )
 
 type AccountStatusesResponse struct {
@@ -90,6 +93,10 @@ func (b *AccountStatusesBackend) getAccountStatusResponseFactory(
 	return func(ctx context.Context, height uint64) (interface{}, error) {
 		eventsResponse, err := b.eventsRetriever.GetAllEventsResponse(ctx, height)
 		if err != nil {
+			if errors.Is(err, storage.ErrNotFound) ||
+				errors.Is(err, storage.ErrHeightNotIndexed) {
+				return nil, fmt.Errorf("block %d is not available yet: %w", height, subscription.ErrBlockNotReady)
+			}
 			return nil, err
 		}
 		filteredProtocolEvents := filter.Filter(eventsResponse.Events)
diff --git a/engine/access/state_stream/backend/backend_events.go b/engine/access/state_stream/backend/backend_events.go
index 4c9818402dd..b02673749bb 100644
--- a/engine/access/state_stream/backend/backend_events.go
+++ b/engine/access/state_stream/backend/backend_events.go
@@ -2,12 +2,15 @@ package backend
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/rs/zerolog"
 
 	"github.com/onflow/flow-go/engine/access/state_stream"
 	"github.com/onflow/flow-go/engine/access/subscription"
+	"github.com/onflow/flow-go/fvm/errors"
 	"github.com/onflow/flow-go/model/flow"
+	"github.com/onflow/flow-go/storage"
 )
 
 type EventsBackend struct {
@@ -126,12 +129,16 @@ func (b *EventsBackend) SubscribeEventsFromLatest(ctx context.Context, filter st
 // - filter: The event filter used to filter events.
 //
 // Expected errors during normal operation:
-// - codes.NotFound: If block header for the specified block height is not found, if events for the specified block height are not found.
+// - subscription.ErrBlockNotReady: execution data for the given block height is not available.
 func (b *EventsBackend) getResponseFactory(filter state_stream.EventFilter) subscription.GetDataByHeightFunc {
 	return func(ctx context.Context, height uint64) (response interface{}, err error) {
 		eventsResponse, err := b.eventsRetriever.GetAllEventsResponse(ctx, height)
 		if err != nil {
-			return nil, err
+			if errors.Is(err, storage.ErrNotFound) ||
+				errors.Is(err, storage.ErrHeightNotIndexed) {
+				return nil, subscription.ErrBlockNotReady
+			}
+			return nil, fmt.Errorf("block %d is not available yet: %w", height, subscription.ErrBlockNotReady)
 		}
 
 		eventsResponse.Events = filter.Filter(eventsResponse.Events)
diff --git a/engine/access/state_stream/backend/backend_executiondata.go b/engine/access/state_stream/backend/backend_executiondata.go
index c1821593ffd..fb161a126f6 100644
--- a/engine/access/state_stream/backend/backend_executiondata.go
+++ b/engine/access/state_stream/backend/backend_executiondata.go
@@ -34,6 +34,9 @@ type ExecutionDataBackend struct {
 func (b *ExecutionDataBackend) GetExecutionDataByBlockID(ctx context.Context, blockID flow.Identifier) (*execution_data.BlockExecutionData, error) {
 	header, err := b.headers.ByBlockID(blockID)
 	if err != nil {
+		if errors.Is(err, storage.ErrNotFound) {
+			return nil, fmt.Errorf("could not get block header for %s: %w", blockID, subscription.ErrBlockNotReady)
+		}
 		return nil, fmt.Errorf("could not get block header for %s: %w", blockID, err)
 	}
 
@@ -41,8 +44,8 @@ func (b *ExecutionDataBackend) GetExecutionDataByBlockID(ctx context.Context, bl
 
 	if err != nil {
 		// need custom not found handler due to blob not found error
-		if errors.Is(err, storage.ErrNotFound) || execution_data.IsBlobNotFoundError(err) {
-			return nil, status.Errorf(codes.NotFound, "could not find execution data: %v", err)
+		if errors.Is(err, subscription.ErrBlockNotReady) {
+			return nil, status.Errorf(codes.NotFound, "could not find execution data: %v", subscription.ErrBlockNotReady)
 		}
 
 		return nil, rpc.ConvertError(err, "could not get execution data", codes.Internal)

From 57f0f89ee051d5a0c66216089b8e33732cc6b133 Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Thu, 11 Apr 2024 15:16:26 +0300
Subject: [PATCH 05/10] Changed if statements

---
 .../access/state_stream/backend/backend_executiondata.go   | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/engine/access/state_stream/backend/backend_executiondata.go b/engine/access/state_stream/backend/backend_executiondata.go
index fb161a126f6..4fdad151df5 100644
--- a/engine/access/state_stream/backend/backend_executiondata.go
+++ b/engine/access/state_stream/backend/backend_executiondata.go
@@ -43,12 +43,11 @@ func (b *ExecutionDataBackend) GetExecutionDataByBlockID(ctx context.Context, bl
 	executionData, err := b.getExecutionData(ctx, header.Height)
 
 	if err != nil {
-		// need custom not found handler due to blob not found error
-		if errors.Is(err, subscription.ErrBlockNotReady) {
-			return nil, status.Errorf(codes.NotFound, "could not find execution data: %v", subscription.ErrBlockNotReady)
+		if !errors.Is(err, subscription.ErrBlockNotReady) {
+			return nil, rpc.ConvertError(err, "could not get execution data", codes.Internal)
 		}
 
-		return nil, rpc.ConvertError(err, "could not get execution data", codes.Internal)
+		return nil, status.Errorf(codes.NotFound, "could not find execution data: %v", subscription.ErrBlockNotReady)
 	}
 
 	return executionData.BlockExecutionData, nil

From 070a5a3dcf5baca310a7cd6b9aa63cdbe35f7fc1 Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Wed, 17 Apr 2024 14:12:50 +0300
Subject: [PATCH 06/10] Fixed comments:

---
 engine/access/rpc/backend/backend_network.go     |  2 +-
 .../access/rpc/backend/backend_stream_blocks.go  |  4 ++--
 engine/access/state_stream/backend/backend.go    | 15 +++++----------
 .../backend/backend_executiondata.go             | 16 +++-------------
 engine/access/subscription/streamer.go           |  7 +------
 5 files changed, 12 insertions(+), 32 deletions(-)

diff --git a/engine/access/rpc/backend/backend_network.go b/engine/access/rpc/backend/backend_network.go
index 1a1c87722be..a91483519b3 100644
--- a/engine/access/rpc/backend/backend_network.go
+++ b/engine/access/rpc/backend/backend_network.go
@@ -146,7 +146,7 @@ func (b *backendNetwork) GetProtocolStateSnapshotByBlockID(_ context.Context, bl
 // The block must be finalized (otherwise the by-height query is ambiguous).
 // Expected errors during normal operation:
 //   - status.Error[codes.NotFound] - No block with the given height was found.
-//     The block height may or may not be finalized in the future; the client can retry later.
+//     The block height may or may not be finalized in the future; the client can r etry later.
 //   - status.Error[codes.InvalidArgument] - A block was found, however its sealing segment spans an epoch phase transition,
 //     yielding an invalid snapshot. Therefore we will never return a snapshot for this block height.
 func (b *backendNetwork) GetProtocolStateSnapshotByHeight(_ context.Context, blockHeight uint64) ([]byte, error) {
diff --git a/engine/access/rpc/backend/backend_stream_blocks.go b/engine/access/rpc/backend/backend_stream_blocks.go
index c31afb7f7fc..85b522b2d2c 100644
--- a/engine/access/rpc/backend/backend_stream_blocks.go
+++ b/engine/access/rpc/backend/backend_stream_blocks.go
@@ -295,7 +295,7 @@ func (b *backendSubscribeBlocks) getBlockHeader(height uint64, expectedBlockStat
 	header, err := b.headers.ByHeight(height)
 	if err != nil {
 		if errors.Is(err, storage.ErrNotFound) {
-			return nil, fmt.Errorf("failed to retrieve block ID for height %d: %w", height, subscription.ErrBlockNotReady)
+			return nil, fmt.Errorf("failed to retrieve block header for height %d: %w", height, subscription.ErrBlockNotReady)
 		}
 		return nil, err
 	}
@@ -316,7 +316,7 @@ func (b *backendSubscribeBlocks) getBlock(height uint64, expectedBlockStatus flo
 	block, err := b.blocks.ByHeight(height)
 	if err != nil {
 		if errors.Is(err, storage.ErrNotFound) {
-			return nil, fmt.Errorf("failed to retrieve block ID for height %d: %w", height, subscription.ErrBlockNotReady)
+			return nil, fmt.Errorf("failed to retrieve block for height %d: %w", height, subscription.ErrBlockNotReady)
 		}
 		return nil, err
 	}
diff --git a/engine/access/state_stream/backend/backend.go b/engine/access/state_stream/backend/backend.go
index 13ec8bd33ce..78a4f788577 100644
--- a/engine/access/state_stream/backend/backend.go
+++ b/engine/access/state_stream/backend/backend.go
@@ -2,6 +2,7 @@ package backend
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"time"
 
@@ -12,7 +13,6 @@ import (
 	"github.com/onflow/flow-go/engine/access/index"
 	"github.com/onflow/flow-go/engine/access/state_stream"
 	"github.com/onflow/flow-go/engine/access/subscription"
-	"github.com/onflow/flow-go/fvm/errors"
 	"github.com/onflow/flow-go/model/flow"
 	"github.com/onflow/flow-go/module/execution"
 	"github.com/onflow/flow-go/module/executiondatasync/execution_data"
@@ -155,16 +155,11 @@ func (b *StateStreamBackend) getExecutionData(ctx context.Context, height uint64
 	}
 
 	execData, err := b.execDataCache.ByHeight(ctx, height)
-	if err != nil {
-		var errMsg error
-		if errors.Is(err, storage.ErrNotFound) ||
-			execution_data.IsBlobNotFoundError(err) {
-			errMsg = subscription.ErrBlockNotReady
-		} else {
-			errMsg = err
-		}
-		return nil, fmt.Errorf("could not get execution data for block %d: %w", height, errMsg)
+	if errors.Is(err, storage.ErrNotFound) ||
+		execution_data.IsBlobNotFoundError(err) {
+		err = errors.Join(err, subscription.ErrBlockNotReady)
 	}
+	return nil, fmt.Errorf("could not get execution data for block %d: %w", height, err)
 
 	return execData, nil
 }
diff --git a/engine/access/state_stream/backend/backend_executiondata.go b/engine/access/state_stream/backend/backend_executiondata.go
index 4fdad151df5..3807d93fd9c 100644
--- a/engine/access/state_stream/backend/backend_executiondata.go
+++ b/engine/access/state_stream/backend/backend_executiondata.go
@@ -2,18 +2,15 @@ package backend
 
 import (
 	"context"
-	"errors"
 	"fmt"
 
-	"github.com/rs/zerolog"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/status"
-
 	"github.com/onflow/flow-go/engine/access/subscription"
 	"github.com/onflow/flow-go/engine/common/rpc"
 	"github.com/onflow/flow-go/model/flow"
 	"github.com/onflow/flow-go/module/executiondatasync/execution_data"
 	"github.com/onflow/flow-go/storage"
+	"github.com/rs/zerolog"
+	"google.golang.org/grpc/codes"
 )
 
 type ExecutionDataResponse struct {
@@ -34,20 +31,13 @@ type ExecutionDataBackend struct {
 func (b *ExecutionDataBackend) GetExecutionDataByBlockID(ctx context.Context, blockID flow.Identifier) (*execution_data.BlockExecutionData, error) {
 	header, err := b.headers.ByBlockID(blockID)
 	if err != nil {
-		if errors.Is(err, storage.ErrNotFound) {
-			return nil, fmt.Errorf("could not get block header for %s: %w", blockID, subscription.ErrBlockNotReady)
-		}
 		return nil, fmt.Errorf("could not get block header for %s: %w", blockID, err)
 	}
 
 	executionData, err := b.getExecutionData(ctx, header.Height)
 
 	if err != nil {
-		if !errors.Is(err, subscription.ErrBlockNotReady) {
-			return nil, rpc.ConvertError(err, "could not get execution data", codes.Internal)
-		}
-
-		return nil, status.Errorf(codes.NotFound, "could not find execution data: %v", subscription.ErrBlockNotReady)
+		return nil, rpc.ConvertError(err, "could not get execution data", codes.Internal)
 	}
 
 	return executionData.BlockExecutionData, nil
diff --git a/engine/access/subscription/streamer.go b/engine/access/subscription/streamer.go
index 11531387200..40c8166a0c6 100644
--- a/engine/access/subscription/streamer.go
+++ b/engine/access/subscription/streamer.go
@@ -10,8 +10,6 @@ import (
 	"golang.org/x/time/rate"
 
 	"github.com/onflow/flow-go/engine"
-	"github.com/onflow/flow-go/module/executiondatasync/execution_data"
-	"github.com/onflow/flow-go/storage"
 )
 
 // ErrBlockNotReady represents an error indicating that a block is not yet available or ready.
@@ -105,10 +103,7 @@ func (s *Streamer) sendAllAvailable(ctx context.Context) error {
 		}
 
 		if err != nil {
-			if errors.Is(err, storage.ErrNotFound) ||
-				errors.Is(err, storage.ErrHeightNotIndexed) ||
-				execution_data.IsBlobNotFoundError(err) ||
-				errors.Is(err, ErrBlockNotReady) {
+			if errors.Is(err, ErrBlockNotReady) {
 				// no more available
 				return nil
 			}

From 57f4e09218490f1dfa9385967e635568e045e33a Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Wed, 17 Apr 2024 14:47:11 +0300
Subject: [PATCH 07/10] Linted

---
 engine/access/state_stream/backend/backend.go         | 11 +++++++----
 .../state_stream/backend/backend_executiondata.go     |  5 +++--
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/engine/access/state_stream/backend/backend.go b/engine/access/state_stream/backend/backend.go
index 78a4f788577..2515cabb32b 100644
--- a/engine/access/state_stream/backend/backend.go
+++ b/engine/access/state_stream/backend/backend.go
@@ -155,11 +155,14 @@ func (b *StateStreamBackend) getExecutionData(ctx context.Context, height uint64
 	}
 
 	execData, err := b.execDataCache.ByHeight(ctx, height)
-	if errors.Is(err, storage.ErrNotFound) ||
-		execution_data.IsBlobNotFoundError(err) {
-		err = errors.Join(err, subscription.ErrBlockNotReady)
+	if err != nil {
+		if errors.Is(err, storage.ErrNotFound) ||
+			execution_data.IsBlobNotFoundError(err) {
+			err = errors.Join(err, subscription.ErrBlockNotReady)
+			return nil, fmt.Errorf("could not get execution data for block %d: %w", height, err)
+		}
+		return nil, fmt.Errorf("could not get execution data for block %d: %w", height, err)
 	}
-	return nil, fmt.Errorf("could not get execution data for block %d: %w", height, err)
 
 	return execData, nil
 }
diff --git a/engine/access/state_stream/backend/backend_executiondata.go b/engine/access/state_stream/backend/backend_executiondata.go
index 3807d93fd9c..085f7944f2a 100644
--- a/engine/access/state_stream/backend/backend_executiondata.go
+++ b/engine/access/state_stream/backend/backend_executiondata.go
@@ -4,13 +4,14 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/rs/zerolog"
+	"google.golang.org/grpc/codes"
+
 	"github.com/onflow/flow-go/engine/access/subscription"
 	"github.com/onflow/flow-go/engine/common/rpc"
 	"github.com/onflow/flow-go/model/flow"
 	"github.com/onflow/flow-go/module/executiondatasync/execution_data"
 	"github.com/onflow/flow-go/storage"
-	"github.com/rs/zerolog"
-	"google.golang.org/grpc/codes"
 )
 
 type ExecutionDataResponse struct {

From 23acd32b1e1829af8e617451010ba244287353a3 Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Wed, 17 Apr 2024 15:25:36 +0300
Subject: [PATCH 08/10] Added removed part

---
 engine/access/rpc/backend/backend_network.go                | 2 +-
 engine/access/state_stream/backend/backend_executiondata.go | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/engine/access/rpc/backend/backend_network.go b/engine/access/rpc/backend/backend_network.go
index a91483519b3..1a1c87722be 100644
--- a/engine/access/rpc/backend/backend_network.go
+++ b/engine/access/rpc/backend/backend_network.go
@@ -146,7 +146,7 @@ func (b *backendNetwork) GetProtocolStateSnapshotByBlockID(_ context.Context, bl
 // The block must be finalized (otherwise the by-height query is ambiguous).
 // Expected errors during normal operation:
 //   - status.Error[codes.NotFound] - No block with the given height was found.
-//     The block height may or may not be finalized in the future; the client can r etry later.
+//     The block height may or may not be finalized in the future; the client can retry later.
 //   - status.Error[codes.InvalidArgument] - A block was found, however its sealing segment spans an epoch phase transition,
 //     yielding an invalid snapshot. Therefore we will never return a snapshot for this block height.
 func (b *backendNetwork) GetProtocolStateSnapshotByHeight(_ context.Context, blockHeight uint64) ([]byte, error) {
diff --git a/engine/access/state_stream/backend/backend_executiondata.go b/engine/access/state_stream/backend/backend_executiondata.go
index 085f7944f2a..34627007273 100644
--- a/engine/access/state_stream/backend/backend_executiondata.go
+++ b/engine/access/state_stream/backend/backend_executiondata.go
@@ -2,10 +2,12 @@ package backend
 
 import (
 	"context"
+	"errors"
 	"fmt"
 
 	"github.com/rs/zerolog"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 
 	"github.com/onflow/flow-go/engine/access/subscription"
 	"github.com/onflow/flow-go/engine/common/rpc"
@@ -38,6 +40,9 @@ func (b *ExecutionDataBackend) GetExecutionDataByBlockID(ctx context.Context, bl
 	executionData, err := b.getExecutionData(ctx, header.Height)
 
 	if err != nil {
+		if errors.Is(err, storage.ErrNotFound) || execution_data.IsBlobNotFoundError(err) {
+			return nil, status.Errorf(codes.NotFound, "could not find execution data: %v", err)
+		}
 		return nil, rpc.ConvertError(err, "could not get execution data", codes.Internal)
 	}
 

From 8a572be51dc6a215e8c9f6c9f247b3637febfd33 Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Wed, 17 Apr 2024 15:26:40 +0300
Subject: [PATCH 09/10] Added back comment

---
 engine/access/state_stream/backend/backend_executiondata.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/engine/access/state_stream/backend/backend_executiondata.go b/engine/access/state_stream/backend/backend_executiondata.go
index 34627007273..c1821593ffd 100644
--- a/engine/access/state_stream/backend/backend_executiondata.go
+++ b/engine/access/state_stream/backend/backend_executiondata.go
@@ -40,9 +40,11 @@ func (b *ExecutionDataBackend) GetExecutionDataByBlockID(ctx context.Context, bl
 	executionData, err := b.getExecutionData(ctx, header.Height)
 
 	if err != nil {
+		// need custom not found handler due to blob not found error
 		if errors.Is(err, storage.ErrNotFound) || execution_data.IsBlobNotFoundError(err) {
 			return nil, status.Errorf(codes.NotFound, "could not find execution data: %v", err)
 		}
+
 		return nil, rpc.ConvertError(err, "could not get execution data", codes.Internal)
 	}
 

From 868474d295247df6c486f28003652b13c05d76c9 Mon Sep 17 00:00:00 2001
From: Andrii <andriy.dyachuk95@gmail.com>
Date: Thu, 18 Apr 2024 12:40:15 +0300
Subject: [PATCH 10/10] Changed godoc

---
 engine/access/rpc/backend/backend_stream_blocks.go          | 4 ++--
 .../access/state_stream/backend/backend_account_statuses.go | 6 +++++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/engine/access/rpc/backend/backend_stream_blocks.go b/engine/access/rpc/backend/backend_stream_blocks.go
index 85b522b2d2c..cddd59a63ef 100644
--- a/engine/access/rpc/backend/backend_stream_blocks.go
+++ b/engine/access/rpc/backend/backend_stream_blocks.go
@@ -284,7 +284,7 @@ func (b *backendSubscribeBlocks) getBlockDigestResponse(blockStatus flow.BlockSt
 
 // getBlockHeader returns the block header for the given block height.
 // Expected errors during normal operation:
-// - storage.ErrNotFound: block for the given block height is not available.
+// - subscription.ErrBlockNotReady: block for the given block height is not available.
 func (b *backendSubscribeBlocks) getBlockHeader(height uint64, expectedBlockStatus flow.BlockStatus) (*flow.Header, error) {
 	err := b.validateHeight(height, expectedBlockStatus)
 	if err != nil {
@@ -305,7 +305,7 @@ func (b *backendSubscribeBlocks) getBlockHeader(height uint64, expectedBlockStat
 
 // getBlock returns the block for the given block height.
 // Expected errors during normal operation:
-// - storage.ErrNotFound: block for the given block height is not available.
+// - subscription.ErrBlockNotReady: block for the given block height is not available.
 func (b *backendSubscribeBlocks) getBlock(height uint64, expectedBlockStatus flow.BlockStatus) (*flow.Block, error) {
 	err := b.validateHeight(height, expectedBlockStatus)
 	if err != nil {
diff --git a/engine/access/state_stream/backend/backend_account_statuses.go b/engine/access/state_stream/backend/backend_account_statuses.go
index 4accbe26bdf..98a52619ede 100644
--- a/engine/access/state_stream/backend/backend_account_statuses.go
+++ b/engine/access/state_stream/backend/backend_account_statuses.go
@@ -57,7 +57,7 @@ func (b *AccountStatusesBackend) SubscribeAccountStatusesFromStartBlockID(
 // SubscribeAccountStatusesFromStartHeight subscribes to the streaming of account status changes starting from
 // a specific block height, with an optional status filter.
 // Errors:
-// - codes.ErrNotFound if could not get block by  start height.
+// - codes.ErrNotFound if could not get block by start height.
 // - codes.Internal if there is an internal error.
 func (b *AccountStatusesBackend) SubscribeAccountStatusesFromStartHeight(
 	ctx context.Context,
@@ -87,6 +87,10 @@ func (b *AccountStatusesBackend) SubscribeAccountStatusesFromLatestBlock(
 }
 
 // getAccountStatusResponseFactory returns a function that returns the account statuses response for a given height.
+//
+// Errors:
+// - subscription.ErrBlockNotReady: If block header for the specified block height is not found.
+// - error: An error, if any, encountered during getting events from storage or execution data.
 func (b *AccountStatusesBackend) getAccountStatusResponseFactory(
 	filter state_stream.AccountStatusFilter,
 ) subscription.GetDataByHeightFunc {