fix: return 404 on non-existing tx (backport cosmos#10992) (cosmos#11014

)

* fix: return 404 on non-existing tx (cosmos#10992)

(cherry picked from commit 1581289)

# Conflicts:
#	CHANGELOG.md

* fix cl

Co-authored-by: Aleksandr Bezobchuk <alexanderbez@users.noreply.github.com>
Co-authored-by: Aleksandr Bezobchuk <aleks.bezobchuk@gmail.com>

CHANGELOG.md

@@ -37,6 +37,10 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ## [Unreleased]
 
+### Bug Fixes
+
+* (grpc) [\#10985](https://github.com/cosmos/cosmos-sdk/pull/10992) The `/cosmos/tx/v1beta1/txs/{hash}` endpoint returns a 404 when a tx does not exist.
+
 ## [v0.45.0](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.45.0) - 2022-01-18
 
 ### State Machine Breaking

x/auth/tx/service.go

@@ -131,10 +131,18 @@ func (s txServer) GetTx(ctx context.Context, req *txtypes.GetTxRequest) (*txtype
 		return nil, status.Error(codes.InvalidArgument, "request cannot be nil")
 	}
 
+	if len(req.Hash) == 0 {
+		return nil, status.Error(codes.InvalidArgument, "tx hash cannot be empty")
+	}
+
 	// TODO We should also check the proof flag in gRPC header.
 	// https://github.com/cosmos/cosmos-sdk/issues/7036.
 	result, err := QueryTx(s.clientCtx, req.Hash)
 	if err != nil {
+		if strings.Contains(err.Error(), "not found") {
+			return nil, status.Errorf(codes.NotFound, "tx not found: %s", req.Hash)
+		}
+
 		return nil, err
 	}