From e51f274f42efd56b83b0568105a3aa4e85d6f6b9 Mon Sep 17 00:00:00 2001
From: Simon Jentzsch <simon@slock.it>
Date: Thu, 18 Oct 2018 12:59:00 +0200
Subject: [PATCH] handle errors correctly

---
 core/state/statedb.go  | 19 ++++++++++---------
 core/vm/interface.go   |  4 ++--
 internal/ethapi/api.go | 14 ++++++++++++--
 3 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/core/state/statedb.go b/core/state/statedb.go
index c76bcfb2b6..6d229f748a 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -18,6 +18,7 @@
 package state
 
 import (
+	"errors"
 	"fmt"
 	"math/big"
 	"sort"
@@ -264,22 +265,22 @@ func (n *ProofList) Put(key []byte, value []byte) error {
 	return nil
 }
 
-// returns the MerkleProof for a given Account
-func (self *StateDB) GetProof(a common.Address) [][]byte {
+// GetProof returns the MerkleProof for a given Account
+func (self *StateDB) GetProof(a common.Address) ([][]byte, error) {
 	var proof ProofList
-	self.trie.Prove(crypto.Keccak256(a.Bytes()), 0, &proof)
-	return proof
+	err := self.trie.Prove(crypto.Keccak256(a.Bytes()), 0, &proof)
+	return proof, err
 }
 
-// returns the StorageProof for given key
-func (self *StateDB) GetStorageProof(a common.Address, key common.Hash) [][]byte {
+// GetProof returns the StorageProof for given key
+func (self *StateDB) GetStorageProof(a common.Address, key common.Hash) ([][]byte, error) {
 	trie := self.StorageTrie(a)
 	if trie == nil {
-		return [][]byte{}
+		return [][]byte{}, errors.New("storage trie for requested address does not exist")
 	}
 	var proof ProofList
-	trie.Prove(crypto.Keccak256(key.Bytes()), 0, &proof)
-	return proof
+	err := trie.Prove(crypto.Keccak256(key.Bytes()), 0, &proof)
+	return proof, err
 }
 
 // GetCommittedState retrieves a value from the given account's committed storage trie.
diff --git a/core/vm/interface.go b/core/vm/interface.go
index 5cefd54d7a..fe2f3d713e 100644
--- a/core/vm/interface.go
+++ b/core/vm/interface.go
@@ -35,8 +35,8 @@ type StateDB interface {
 	SetNonce(common.Address, uint64)
 
 	GetCodeHash(common.Address) common.Hash
-	GetProof(common.Address) [][]byte
-	GetStorageProof(common.Address, common.Hash) [][]byte
+	GetProof(common.Address) ([][]byte, error)
+	GetStorageProof(common.Address, common.Hash) ([][]byte, error)
 	GetCode(common.Address) []byte
 	SetCode(common.Address, []byte)
 	GetCodeSize(common.Address) int
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 284039d3e6..fd60242e69 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -541,15 +541,25 @@ func (s *PublicBlockChainAPI) GetProof(ctx context.Context, address common.Addre
 	// create the proof for the storageKeys
 	for i, key := range storageKeys {
 		if storageTrie != nil {
-			storageProof[i] = StorageResult{key, state.GetState(address, common.HexToHash(key)), common.ToHexArray(state.GetStorageProof(address, common.HexToHash(key)))}
+			proof, storageError := state.GetStorageProof(address, common.HexToHash(key))
+			if storageError != nil {
+				return nil, storageError
+			}
+			storageProof[i] = StorageResult{key, state.GetState(address, common.HexToHash(key)), common.ToHexArray(proof)}
 		} else {
 			storageProof[i] = StorageResult{key, common.Hash{}, []string{}}
 		}
 	}
 
+	// create the accountProof
+	accountProof, proofErr := state.GetProof(address)
+	if proofErr != nil {
+		return nil, proofErr
+	}
+
 	return &AccountResult{
 		Address:      address,
-		AccountProof: common.ToHexArray(state.GetProof(address)),
+		AccountProof: common.ToHexArray(accountProof),
 		Balance:      (*hexutil.Big)(state.GetBalance(address)),
 		CodeHash:     codeHash,
 		Nonce:        hexutil.Uint64(state.GetNonce(address)),