fix: split constructor args for verification

apps/explorer/lib/explorer/smart_contract/solidity/code_compiler.ex

@@ -5,6 +5,8 @@ defmodule Explorer.SmartContract.Solidity.CodeCompiler do
 
   alias Explorer.SmartContract.SolcDownloader
 
+  require Logger
+
   @new_contract_name "New.sol"
   @allowed_evm_versions ["homestead", "tangerineWhistle", "spuriousDragon", "byzantium", "constantinople", "petersburg"]
 
@@ -101,7 +103,8 @@ defmodule Explorer.SmartContract.Solidity.CodeCompiler do
           ]
         )
 
-      with {:ok, contracts} <- Jason.decode(response),
+      with {:ok, decoded} <- Jason.decode(response),
+           {:ok, contracts} <- get_contracts(decoded),
            %{"abi" => abi, "evm" => %{"deployedBytecode" => %{"object" => bytecode}}} <-
              get_contract_info(contracts, name) do
         {:ok, %{"abi" => abi, "bytecode" => bytecode, "name" => name}}
@@ -113,7 +116,9 @@ defmodule Explorer.SmartContract.Solidity.CodeCompiler do
           {:error, reason}
 
         error ->
-          parse_error(error)
+          error = parse_error(error)
+          Logger.warn(["There was an error compiling a provided contract: ", inspect(error)])
+          {:error, :compilation}
       end
     else
       {:error, :compilation}
@@ -139,10 +144,15 @@ defmodule Explorer.SmartContract.Solidity.CodeCompiler do
     end
   end
 
-  def parse_error(%{"error" => error}), do: {:error, [error]}
-  def parse_error(%{"errors" => errors}), do: {:error, errors}
+  def parse_error({:error, %{"error" => error}}), do: {:error, [error]}
+  def parse_error({:error, %{"errors" => errors}}), do: {:error, errors}
   def parse_error({:error, _} = error), do: error
 
+  # Older solc-bin versions don't use filename as contract key
+  defp get_contracts(%{"contracts" => %{"New.sol" => contracts}}), do: {:ok, contracts}
+  defp get_contracts(%{"contracts" => %{"" => contracts}}), do: {:ok, contracts}
+  defp get_contracts(response), do: {:error, response}
+
   defp optimize_value(false), do: "0"
   defp optimize_value("false"), do: "0"
 

apps/explorer/lib/explorer/smart_contract/verifier/constructor_arguments.ex

@@ -7,20 +7,21 @@ defmodule Explorer.SmartContract.Verifier.ConstructorArguments do
 
   def verify(address_hash, arguments_data) do
     arguments_data = String.replace(arguments_data, "0x", "")
-    creation_input_data = Chain.contract_creation_input_data(address_hash)
 
-    data_with_swarm =
-      creation_input_data
-      |> String.split("0029")
-      |> List.first()
-      |> Kernel.<>("0029")
+    address_hash
+    |> Chain.contract_creation_input_data()
+    |> String.replace("0x", "")
+    |> extract_constructor_arguments()
+    |> Kernel.==(arguments_data)
+  end
+
+  defp extract_constructor_arguments(<<>>), do: ""
 
-    expected_arguments_data =
-      creation_input_data
-      |> String.split(data_with_swarm)
-      |> List.last()
-      |> String.replace("0x", "")
+  defp extract_constructor_arguments("a165627a7a72305820" <> <<_::binary-size(64)>> <> "0029" <> constructor_arguments) do
+    constructor_arguments
+  end
 
-    expected_arguments_data == arguments_data
+  defp extract_constructor_arguments(<<_::binary-size(2)>> <> rest) do
+    extract_constructor_arguments(rest)
   end
 end

apps/explorer/priv/compile_solc.js

@@ -39,6 +39,4 @@ const input = {
 
 
 const output = JSON.parse(solc.compile(JSON.stringify(input)))
-/** Older solc-bin versions don't use filename as contract key */
-const response = output.contracts[newContractName] || output.contracts['']
-console.log(JSON.stringify(response));
+console.log(JSON.stringify(output));

apps/explorer/test/explorer/smart_contract/verifier/constructor_arguments_test.exs

@@ -7,17 +7,19 @@ defmodule Explorer.SmartContract.Verifier.ConstructorArgumentsTest do
   alias Explorer.SmartContract.Verifier.ConstructorArguments
 
   test "veriies constructor constructor arguments with whisper data" do
-    constructor_arguments = "0x0405"
+    constructor_arguments = Base.encode16(:crypto.strong_rand_bytes(64), case: :lower)
     address = insert(:address)
 
-    input = %Data{
-      bytes:
-        <<1, 2, 3, 93, 148, 60, 87, 91, 232, 162, 174, 226, 187, 119, 55, 167, 101, 253, 210, 198, 228, 155, 116, 205,
-          44, 146, 171, 15, 168, 228, 40, 45, 26, 117, 174, 0, 41, 4, 5>>
+    input =
+      "a165627a7a72305820" <>
+        Base.encode16(:crypto.strong_rand_bytes(32), case: :lower) <> "0029" <> constructor_arguments
+
+    input_data = %Data{
+      bytes: Base.decode16!(input, case: :lower)
     }
 
     :transaction
-    |> insert(created_contract_address_hash: address.hash, input: input)
+    |> insert(created_contract_address_hash: address.hash, input: input_data)
     |> with_block()
 
     assert ConstructorArguments.verify(address.hash, constructor_arguments)