From 8d51a70d6d1c71fd32af74d151965394eecd13d2 Mon Sep 17 00:00:00 2001
From: Calvin Lau <38898718+calvinaco@users.noreply.github.com>
Date: Mon, 12 Jul 2021 20:45:13 +0800
Subject: [PATCH] rpc: fix `GetBlockByHash` crash on block not found (#256)
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* Fix GetBlockByHash crashed on block not found

* Add and update log message based on review

* Apply suggestions from code review

* Apply suggestions from code review

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>
---
 ethereum/rpc/backend/backend.go | 14 ++++++++++++--
 tests/rpc/rpc_test.go           | 27 +++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/ethereum/rpc/backend/backend.go b/ethereum/rpc/backend/backend.go
index b8452770..1065057e 100644
--- a/ethereum/rpc/backend/backend.go
+++ b/ethereum/rpc/backend/backend.go
@@ -112,11 +112,16 @@ func (e *EVMBackend) GetBlockByNumber(blockNum types.BlockNumber, fullTx bool) (
 	if err != nil {
 		// e.logger.Debugf("GetBlockByNumber safely bumping down from %d to latest", height)
 		if resBlock, err = e.clientCtx.Client.Block(e.ctx, nil); err != nil {
-			e.logger.Debugln("GetBlockByNumber failed to get latest block")
+			e.logger.WithError(err).Debugln("GetBlockByNumber failed to get latest block")
 			return nil, nil
 		}
 	}
 
+	if resBlock.Block == nil {
+		e.logger.Debugln("GetBlockByNumber block not found", "height", height)
+		return nil, nil
+	}
+
 	res, err := e.EthBlockFromTendermint(e.clientCtx, e.queryClient, resBlock.Block, fullTx)
 	if err != nil {
 		e.logger.WithError(err).Debugf("EthBlockFromTendermint failed with block %s", resBlock.Block.String())
@@ -129,10 +134,15 @@ func (e *EVMBackend) GetBlockByNumber(blockNum types.BlockNumber, fullTx bool) (
 func (e *EVMBackend) GetBlockByHash(hash common.Hash, fullTx bool) (map[string]interface{}, error) {
 	resBlock, err := e.clientCtx.Client.BlockByHash(e.ctx, hash.Bytes())
 	if err != nil {
-		e.logger.Warningf("BlockByHash failed for %s", hash.Hex())
+		e.logger.WithError(err).Debugln("BlockByHash block not found", "hash", hash.Hex())
 		return nil, err
 	}
 
+	if resBlock.Block == nil {
+		e.logger.Debugln("BlockByHash block not found", "hash", hash.Hex())
+		return nil, nil
+	}
+
 	return e.EthBlockFromTendermint(e.clientCtx, e.queryClient, resBlock.Block, fullTx)
 }
 
diff --git a/tests/rpc/rpc_test.go b/tests/rpc/rpc_test.go
index 12045672..c4466792 100644
--- a/tests/rpc/rpc_test.go
+++ b/tests/rpc/rpc_test.go
@@ -799,6 +799,33 @@ func TestEth_ExportAccount_WithStorage(t *testing.T) {
 	require.NotEqual(t, evmtypes.Storage(nil), account.Storage)
 }
 
+func TestEth_GetBlockByHash(t *testing.T) {
+	param := []interface{}{"0x1", false}
+	rpcRes := call(t, "eth_getBlockByNumber", param)
+
+	block := make(map[string]interface{})
+	err := json.Unmarshal(rpcRes.Result, &block)
+	blockHash := block["hash"].(string)
+
+	param = []interface{}{blockHash, false}
+	rpcRes = call(t, "eth_getBlockByHash", param)
+	block = make(map[string]interface{})
+	err = json.Unmarshal(rpcRes.Result, &block)
+	require.NoError(t, err)
+	require.Equal(t, "0x1", block["number"].(string))
+}
+
+func TestEth_GetBlockByHash_BlockHashNotFound(t *testing.T) {
+	anyBlockHash := "0xb3b20624f8f0f86eb50dd04688409e5cea4bd02d700bf6e79e9384d47d6a5a35"
+	param := []interface{}{anyBlockHash, false}
+	rpcRes := call(t, "eth_getBlockByHash", param)
+
+	var result interface{}
+	err := json.Unmarshal(rpcRes.Result, &result)
+	require.NoError(t, err)
+	require.Nil(t, result)
+}
+
 func TestEth_GetBlockByNumber(t *testing.T) {
 	param := []interface{}{"0x1", false}
 	rpcRes := call(t, "eth_getBlockByNumber", param)