Ganache ignores internal transactions

Why:

* We were using the `EthereumJSONRPC.Geth` variant for Ganache but we
recently learned that it doesn't support the `tracer` option for
[debug_traceTransaction](https://github.com/ethereum/go-ethereum/wiki/Management-APIs#debug_tracetransaction).
This `tracer` option is what we currently use to fetch internal
transactions for Geth. This was the cause of errors as shown on issue
1152 (link below).
* Issue link:
https://github.com/poanetwork/blockscout/issues/1152

This change addresses the need by:

* Creating `EthereumJSONRPC.Ganache`. It ignores fetching beneficiaries,
internal transactions, and pending transactions.
* Editing ganache config to use the `EthereumJSONRPC.Ganache` variant
instead of `EthereumJSONRPC.Geth`.
* Updating inaccurate doc in `EthereumJSONRPC.Geth`. It previously said
fetching internal transactions was not supported for Geth which is
inaccurate.

apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/ganache.ex

@@ -0,0 +1,31 @@
+defmodule EthereumJSONRPC.Ganache do
+  @moduledoc """
+  Ethereum JSONRPC methods that are only supported by [Ganache](https://github.com/trufflesuite/ganache-core#implemented-methods).
+  """
+
+  @behaviour EthereumJSONRPC.Variant
+
+  @doc """
+  Block reward contract beneficiary fetching is not supported currently for Ganache.
+
+  To signal to the caller that fetching is not supported, `:ignore` is returned.
+  """
+  @impl EthereumJSONRPC.Variant
+  def fetch_beneficiaries(_block_range, _json_rpc_named_arguments), do: :ignore
+
+  @doc """
+  Internal transaction fetching is not currently supported for Ganache.
+
+  To signal to the caller that fetching is not supported, `:ignore` is returned.
+  """
+  @impl EthereumJSONRPC.Variant
+  def fetch_internal_transactions(_transactions_params, _json_rpc_named_arguments), do: :ignore
+
+  @doc """
+  Pending transaction fetching is not supported currently for Ganache.
+
+  To signal to the caller that fetching is not supported, `:ignore` is returned.
+  """
+  @impl EthereumJSONRPC.Variant
+  def fetch_pending_transactions(_json_rpc_named_arguments), do: :ignore
+end

apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/geth.ex

@@ -18,9 +18,7 @@ defmodule EthereumJSONRPC.Geth do
   def fetch_beneficiaries(_block_range, _json_rpc_named_arguments), do: :ignore
 
   @doc """
-  Internal transaction fetching is not supported currently for Geth.
-
-  To signal to the caller that fetching is not supported, `:ignore` is returned.
+  Fetches the `t:Explorer.Chain.InternalTransaction.changeset/2` params.
   """
   @impl EthereumJSONRPC.Variant
   def fetch_internal_transactions(transactions_params, json_rpc_named_arguments) when is_list(transactions_params) do

apps/explorer/config/dev/ganache.exs

@@ -8,7 +8,7 @@ config :explorer,
       url: System.get_env("ETHEREUM_JSONRPC_HTTP_URL") || "http://localhost:7545",
       http_options: [recv_timeout: 60_000, timeout: 60_000, hackney: [pool: :ethereum_jsonrpc]]
     ],
-    variant: EthereumJSONRPC.Geth
+    variant: EthereumJSONRPC.Ganache
   ],
   subscribe_named_arguments: [
     transport: EthereumJSONRPC.WebSocket,
@@ -16,5 +16,5 @@ config :explorer,
       web_socket: EthereumJSONRPC.WebSocket.WebSocketClient,
       url: System.get_env("ETHEREUM_JSONRPC_WS_URL") || "ws://localhost:7545"
     ],
-    variant: EthereumJSONRPC.Geth
+    variant: EthereumJSONRPC.Ganache
   ]

apps/explorer/config/prod/ganache.exs

@@ -8,7 +8,7 @@ config :explorer,
       url: System.get_env("ETHEREUM_JSONRPC_HTTP_URL") || "http://localhost:7545",
       http_options: [recv_timeout: 60_000, timeout: 60_000, hackney: [pool: :ethereum_jsonrpc]]
     ],
-    variant: EthereumJSONRPC.Geth
+    variant: EthereumJSONRPC.Ganache
   ],
   subscribe_named_arguments: [
     transport: EthereumJSONRPC.WebSocket,
@@ -16,5 +16,5 @@ config :explorer,
       web_socket: EthereumJSONRPC.WebSocket.WebSocketClient,
       url: System.get_env("ETHEREUM_JSONRPC_WS_URL") || "ws://localhost:7545"
     ],
-    variant: EthereumJSONRPC.Geth
+    variant: EthereumJSONRPC.Ganache
   ]

apps/explorer/config/test/ganache.exs

@@ -4,10 +4,10 @@ config :explorer,
   json_rpc_named_arguments: [
     transport: EthereumJSONRPC.Mox,
     transport_options: [],
-    variant: EthereumJSONRPC.Geth
+    variant: EthereumJSONRPC.Ganache
   ],
   subscribe_named_arguments: [
     transport: EthereumJSONRPC.Mox,
     transport_options: [],
-    variant: EthereumJSONRPC.Geth
+    variant: EthereumJSONRPC.Ganache
   ]

apps/indexer/config/dev/ganache.exs

@@ -9,7 +9,7 @@ config :indexer,
       url: System.get_env("ETHEREUM_JSONRPC_HTTP_URL") || "http://localhost:7545",
       http_options: [recv_timeout: 60_000, timeout: 60_000, hackney: [pool: :ethereum_jsonrpc]]
     ],
-    variant: EthereumJSONRPC.Geth
+    variant: EthereumJSONRPC.Ganache
   ],
   subscribe_named_arguments: [
     transport: EthereumJSONRPC.WebSocket,

apps/indexer/config/prod/ganache.exs

@@ -9,7 +9,7 @@ config :indexer,
       url: System.get_env("ETHEREUM_JSONRPC_HTTP_URL") || "http://localhost:7545",
       http_options: [recv_timeout: 60_000, timeout: 60_000, hackney: [pool: :ethereum_jsonrpc]]
     ],
-    variant: EthereumJSONRPC.Geth
+    variant: EthereumJSONRPC.Ganache
   ],
   subscribe_named_arguments: [
     transport: EthereumJSONRPC.WebSocket,