Merge branch 'master' into feature/#1476-add-styles-for-POSDAO-network

* master:
  Update changelog
  Address review comments
  Add a migration to mark all invalid blocks as non-consensus (#1644)
  Force consensus loss for parent block if its hash mismatches parent_hash
  Add regression test for #1644
  feat: add listcontracts endpoint
  fix view test
  use correct type for evm_version
  define evm versions in one place
  fix dialyzer
  set only hours in env var
  fetch transaction period from env variables
  add changelog entry
  add petersburg evm version
  add CHANGELOG entry
  fix credo
  fix tests
  use cache for estimated transaction count
  add transaction count cache

CHANGELOG.md

@@ -2,8 +2,18 @@
 
 ### Features
 
- - [1611](https://github.com/poanetwork/blockscout/pull/1611) - allow setting the first indexing block
- - [1596](https://github.com/poanetwork/blockscout/pull/1596) - add endpoint to create decompiled contracts
+### Fixes
+
+### Chore
+
+
+## 1.3.8-beta
+
+### Features
+
+ - [#1611](https://github.com/poanetwork/blockscout/pull/1611) - allow setting the first indexing block
+ - [#1596](https://github.com/poanetwork/blockscout/pull/1596) - add endpoint to create decompiled contracts
+ - [#1634](https://github.com/poanetwork/blockscout/pull/1634) - add transaction count cache
 
 
 ### Fixes
@@ -14,6 +24,8 @@
  - [#1639](https://github.com/poanetwork/blockscout/pull/1614) - Optimize token holder count updates when importing address current balances
  - [#1643](https://github.com/poanetwork/blockscout/pull/1643) - Set internal_transactions_indexed_at for empty blocks
  - [#1647](https://github.com/poanetwork/blockscout/pull/1647) - Fix typo in view
+ - [#1650](https://github.com/poanetwork/blockscout/pull/1650) - Add petersburg evm version to smart contract verifier
+ - [#1657](https://github.com/poanetwork/blockscout/pull/1657) - Force consensus loss for parent block if its hash mismatches parent_hash
 
 ### Chore
 
@@ -40,6 +52,7 @@
  - [#1589](https://github.com/poanetwork/blockscout/pull/1589) - RPC endpoint to list addresses
  - [#1567](https://github.com/poanetwork/blockscout/pull/1567) - Allow setting different configuration just for realtime fetcher
  - [#1562](https://github.com/poanetwork/blockscout/pull/1562) - Add incoming transactions count to contract view
+ - [#1608](https://github.com/poanetwork/blockscout/pull/1608) - Add listcontracts RPC Endpoint
 
 ### Fixes
 

apps/block_scout_web/lib/block_scout_web/controllers/address_contract_verification_controller.ex

@@ -2,9 +2,7 @@ defmodule BlockScoutWeb.AddressContractVerificationController do
   use BlockScoutWeb, :controller
 
   alias Explorer.Chain.SmartContract
-  alias Explorer.SmartContract.{Publisher, Solidity.CompilerVersion}
-
-  @evm_versions ["homestead", "tangerineWhistle", "spuriousDragon", "byzantium", "constantinople"]
+  alias Explorer.SmartContract.{Publisher, Solidity.CodeCompiler, Solidity.CompilerVersion}
 
   def new(conn, %{"address_id" => address_hash_string}) do
     changeset =
@@ -15,7 +13,11 @@ defmodule BlockScoutWeb.AddressContractVerificationController do
 
     {:ok, compiler_versions} = CompilerVersion.fetch_versions()
 
-    render(conn, "new.html", changeset: changeset, compiler_versions: compiler_versions, evm_versions: @evm_versions)
+    render(conn, "new.html",
+      changeset: changeset,
+      compiler_versions: compiler_versions,
+      evm_versions: CodeCompiler.allowed_evm_versions()
+    )
   end
 
   def create(
@@ -27,7 +29,7 @@ defmodule BlockScoutWeb.AddressContractVerificationController do
           "evm_version" => evm_version
         }
       ) do
-    smart_sontact_with_evm_version = Map.put(smart_contract, "evm_version", evm_version)
+    smart_sontact_with_evm_version = Map.put(smart_contract, "evm_version", evm_version["evm_version"])
 
     case Publisher.publish(address_hash_string, smart_sontact_with_evm_version, external_libraries) do
       {:ok, _smart_contract} ->
@@ -36,7 +38,11 @@ defmodule BlockScoutWeb.AddressContractVerificationController do
       {:error, changeset} ->
         {:ok, compiler_versions} = CompilerVersion.fetch_versions()
 
-        render(conn, "new.html", changeset: changeset, compiler_versions: compiler_versions, evm_versions: @evm_versions)
+        render(conn, "new.html",
+          changeset: changeset,
+          compiler_versions: compiler_versions,
+          evm_versions: CodeCompiler.allowed_evm_versions()
+        )
     end
   end
 end

apps/block_scout_web/lib/block_scout_web/controllers/api/rpc/address_controller.ex

@@ -1,6 +1,7 @@
 defmodule BlockScoutWeb.API.RPC.AddressController do
   use BlockScoutWeb, :controller
 
+  alias BlockScoutWeb.API.RPC.Helpers
   alias Explorer.{Chain, Etherscan}
   alias Explorer.Chain.{Address, Wei}
 
@@ -162,7 +163,7 @@ defmodule BlockScoutWeb.API.RPC.AddressController do
   end
 
   def getminedblocks(conn, params) do
-    options = put_pagination_options(%{}, params)
+    options = Helpers.put_pagination_options(%{}, params)
 
     with {:address_param, {:ok, address_param}} <- fetch_address(params),
          {:format, {:ok, address_hash}} <- to_address_hash(address_param),
@@ -188,7 +189,7 @@ defmodule BlockScoutWeb.API.RPC.AddressController do
   def optional_params(params) do
     %{}
     |> put_order_by_direction(params)
-    |> put_pagination_options(params)
+    |> Helpers.put_pagination_options(params)
     |> put_start_block(params)
     |> put_end_block(params)
     |> put_filter_by(params)
@@ -338,24 +339,6 @@ defmodule BlockScoutWeb.API.RPC.AddressController do
     end
   end
 
-  defp put_pagination_options(options, params) do
-    with %{"page" => page, "offset" => offset} <- params,
-         {page_number, ""} when page_number > 0 <- Integer.parse(page),
-         {page_size, ""} when page_size > 0 <- Integer.parse(offset),
-         :ok <- validate_max_page_size(page_size) do
-      options
-      |> Map.put(:page_number, page_number)
-      |> Map.put(:page_size, page_size)
-    else
-      _ ->
-        options
-    end
-  end
-
-  defp validate_max_page_size(page_size) do
-    if page_size <= Etherscan.page_size_max(), do: :ok, else: :error
-  end
-
   defp put_start_block(options, params) do
     with %{"startblock" => startblock_param} <- params,
          {start_block, ""} <- Integer.parse(startblock_param) do

apps/block_scout_web/lib/block_scout_web/controllers/api/rpc/contract_controller.ex

@@ -1,7 +1,30 @@
 defmodule BlockScoutWeb.API.RPC.ContractController do
   use BlockScoutWeb, :controller
 
+  alias BlockScoutWeb.API.RPC.Helpers
   alias Explorer.Chain
+  alias Explorer.Chain.SmartContract
+
+  def listcontracts(conn, params) do
+    with pagination_options <- Helpers.put_pagination_options(%{}, params),
+         {:params, {:ok, options}} <- {:params, add_filter(pagination_options, params)} do
+      options_with_defaults =
+        options
+        |> Map.put_new(:page_number, 0)
+        |> Map.put_new(:page_size, 10)
+
+      contracts = list_contracts(options_with_defaults)
+
+      conn
+      |> put_status(200)
+      |> render(:listcontracts, %{contracts: contracts})
+    else
+      {:params, {:error, error}} ->
+        conn
+        |> put_status(400)
+        |> render(:error, error: error)
+    end
+  end
 
   def getabi(conn, params) do
     with {:address_param, {:ok, address_param}} <- fetch_address(params),
@@ -24,7 +47,10 @@ defmodule BlockScoutWeb.API.RPC.ContractController do
     with {:address_param, {:ok, address_param}} <- fetch_address(params),
          {:format, {:ok, address_hash}} <- to_address_hash(address_param),
          {:contract, {:ok, contract}} <- to_smart_contract(address_hash) do
-      render(conn, :getsourcecode, %{contract: contract})
+      render(conn, :getsourcecode, %{
+        contract: contract,
+        address_hash: address_hash
+      })
     else
       {:address_param, :error} ->
         render(conn, :error, error: "Query parameter address is required")
@@ -33,10 +59,64 @@ defmodule BlockScoutWeb.API.RPC.ContractController do
         render(conn, :error, error: "Invalid address hash")
 
       {:contract, :not_found} ->
-        render(conn, :getsourcecode, %{contract: nil})
+        render(conn, :getsourcecode, %{contract: nil, address_hash: nil})
+    end
+  end
+
+  defp list_contracts(%{page_number: page_number, page_size: page_size} = opts) do
+    offset = (max(page_number, 1) - 1) * page_size
+
+    case Map.get(opts, :filter) do
+      :verified ->
+        Chain.list_verified_contracts(page_size, offset)
+
+      :decompiled ->
+        Chain.list_decompiled_contracts(page_size, offset)
+
+      :unverified ->
+        Chain.list_unverified_contracts(page_size, offset)
+
+      :not_decompiled ->
+        Chain.list_not_decompiled_contracts(page_size, offset)
+
+      _ ->
+        Chain.list_contracts(page_size, offset)
     end
   end
 
+  defp add_filter(options, params) do
+    with {:param, {:ok, value}} <- {:param, Map.fetch(params, "filter")},
+         {:validation, {:ok, filter}} <- {:validation, contracts_filter(value)} do
+      {:ok, Map.put(options, :filter, filter)}
+    else
+      {:param, :error} -> {:ok, options}
+      {:validation, {:error, error}} -> {:error, error}
+    end
+  end
+
+  defp contracts_filter(nil), do: {:ok, nil}
+  defp contracts_filter(1), do: {:ok, :verified}
+  defp contracts_filter(2), do: {:ok, :decompiled}
+  defp contracts_filter(3), do: {:ok, :unverified}
+  defp contracts_filter(4), do: {:ok, :not_decompiled}
+  defp contracts_filter("verified"), do: {:ok, :verified}
+  defp contracts_filter("decompiled"), do: {:ok, :decompiled}
+  defp contracts_filter("unverified"), do: {:ok, :unverified}
+  defp contracts_filter("not_decompiled"), do: {:ok, :not_decompiled}
+
+  defp contracts_filter(filter) when is_bitstring(filter) do
+    case Integer.parse(filter) do
+      {number, ""} -> contracts_filter(number)
+      _ -> {:error, contracts_filter_error_message(filter)}
+    end
+  end
+
+  defp contracts_filter(filter), do: {:error, contracts_filter_error_message(filter)}
+
+  defp contracts_filter_error_message(filter) do
+    "#{filter} is not a valid value for `filter`. Please use one of: verified, decompiled, unverified, not_decompiled, 1, 2, 3, 4."
+  end
+
   defp fetch_address(params) do
     {:address_param, Map.fetch(params, "address")}
   end
@@ -48,8 +128,11 @@ defmodule BlockScoutWeb.API.RPC.ContractController do
   defp to_smart_contract(address_hash) do
     result =
       case Chain.address_hash_to_smart_contract(address_hash) do
-        nil -> :not_found
-        contract -> {:ok, contract}
+        nil ->
+          :not_found
+
+        contract ->
+          {:ok, SmartContract.preload_decompiled_smart_contract(contract)}
       end
 
     {:contract, result}

apps/block_scout_web/lib/block_scout_web/controllers/api/rpc/helpers.ex

@@ -0,0 +1,42 @@
+defmodule BlockScoutWeb.API.RPC.Helpers do
+  @moduledoc """
+  Small helpers for RPC api controllers.
+  """
+  alias Explorer.Etherscan
+
+  def put_pagination_options(options, params) do
+    options
+    |> put_page_option(params)
+    |> put_offset_option(params)
+  end
+
+  def put_page_option(options, %{"page" => page}) do
+    case Integer.parse(page) do
+      {page_number, ""} when page_number > 0 ->
+        Map.put(options, :page_number, page_number)
+
+      _ ->
+        options
+    end
+  end
+
+  def put_page_option(options, _), do: options
+
+  def put_offset_option(options, %{"offset" => offset}) do
+    with {page_size, ""} when page_size > 0 <- Integer.parse(offset),
+         :ok <- validate_max_page_size(page_size) do
+      Map.put(options, :page_size, page_size)
+    else
+      _ ->
+        options
+    end
+  end
+
+  def put_offset_option(options, _) do
+    options
+  end
+
+  defp validate_max_page_size(page_size) do
+    if page_size <= Etherscan.page_size_max(), do: :ok, else: :error
+  end
+end

apps/block_scout_web/lib/block_scout_web/etherscan.ex

@@ -276,6 +276,45 @@ defmodule BlockScoutWeb.Etherscan do
     "result" => nil
   }
 
+  @contract_listcontracts_example_value %{
+    "status" => "1",
+    "message" => "OK",
+    "result" => [
+      %{
+        "SourceCode" => """
+        pragma solidity >0.4.24;
+
+        contract Test {
+        constructor() public { b = hex"12345678901234567890123456789012"; }
+        event Event(uint indexed a, bytes32 b);
+        event Event2(uint indexed a, bytes32 b);
+        function foo(uint a) public { emit Event(a, b); }
+        bytes32 b;
+        }
+        """,
+        "ABI" => """
+        [{
+        "type":"event",
+        "inputs": [{"name":"a","type":"uint256","indexed":true},{"name":"b","type":"bytes32","indexed":false}],
+        "name":"Event"
+        }, {
+        "type":"event",
+        "inputs": [{"name":"a","type":"uint256","indexed":true},{"name":"b","type":"bytes32","indexed":false}],
+        "name":"Event2"
+        }, {
+        "type":"function",
+        "inputs": [{"name":"a","type":"uint256"}],
+        "name":"foo",
+        "outputs": []
+        }]
+        """,
+        "ContractName" => "Test",
+        "CompilerVersion" => "v0.2.1-2016-01-30-91a6b35",
+        "OptimizationUsed" => "1"
+      }
+    ]
+  }
+
   @contract_getabi_example_value %{
     "status" => "1",
     "message" => "OK",
@@ -742,6 +781,7 @@ defmodule BlockScoutWeb.Etherscan do
   @contract_model %{
     name: "Contract",
     fields: %{
+      "Address" => @address_hash_type,
       "SourceCode" => %{
         type: "contract source code",
         definition: "The contract's source code.",
@@ -757,6 +797,33 @@ defmodule BlockScoutWeb.Etherscan do
         }"
         """
       },
+      "DecompilerVersion" => %{
+        type: "decompiler version",
+        definition: "When decompiled source code is present, the decompiler version with which it was generated.",
+        example: "decompiler.version"
+      },
+      "DecompiledSourceCode" => %{
+        type: "contract decompiled source code",
+        definition: "The contract's decompiled source code.",
+        example: """
+        const name() = 'CryptoKitties'
+        const GEN0_STARTING_PRICE() = 10^16
+        const GEN0_AUCTION_DURATION() = 86400
+        const GEN0_CREATION_LIMIT() = 45000
+        const symbol() = 'CK'
+        const PROMO_CREATION_LIMIT() = 5000
+        def storage:
+          ceoAddress is addr # mask(160, 0) at storage #0
+          cfoAddress is addr # mask(160, 0) at storage #1
+          stor1.768 is uint16 => uint256 # mask(256, 768) at storage #1
+          cooAddress is addr # mask(160, 0) at storage #2
+          stor2.0 is uint256 => uint256 # mask(256, 0) at storage #2
+          paused is uint8 # mask(8, 160) at storage #2
+          stor2.256 is uint256 => uint256 # mask(256, 256) at storage #2
+          stor3 is uint32 #
+        ...<continues>
+        """
+      },
       "ABI" => %{
         type: "ABI",
         definition: "JSON string for the contract's Application Binary Interface (ABI)",
@@ -1343,11 +1410,6 @@ defmodule BlockScoutWeb.Etherscan do
             }
           }
         }
-      },
-      %{
-        code: "200",
-        description: "error",
-        example_value: Jason.encode!(@account_getminedblocks_example_value_error)
       }
     ]
   }
@@ -1635,6 +1697,50 @@ defmodule BlockScoutWeb.Etherscan do
     ]
   }
 
+  @contract_listcontracts_action %{
+    name: "listcontracts",
+    description: "Get a list of contracts, sorted ascending by the time they were first seen by the explorer.",
+    required_params: [],
+    optional_params: [
+      %{
+        key: "page",
+        type: "integer",
+        description:
+          "A nonnegative integer that represents the page number to be used for pagination. 'offset' must be provided in conjunction."
+      },
+      %{
+        key: "offset",
+        type: "integer",
+        description:
+          "A nonnegative integer that represents the maximum number of records to return when paginating. 'page' must be provided in conjunction."
+      },
+      %{
+        key: "filter",
+        type: "string",
+        description:
+          "verified|decompiled|unverified|not_decompiled, or 1|2|3|4 respectively. This requests only contracts with that status."
+      }
+    ],
+    responses: [
+      %{
+        code: "200",
+        description: "successful operation",
+        example_value: Jason.encode!(@contract_listcontracts_example_value),
+        model: %{
+          name: "Result",
+          fields: %{
+            status: @status_type,
+            message: @message_type,
+            result: %{
+              type: "array",
+              array_type: @contract_model
+            }
+          }
+        }
+      }
+    ]
+  }
+
   @contract_getabi_action %{
     name: "getabi",
     description: "Get ABI for verified contract. Also available through a GraphQL 'addresses' query.",
@@ -1862,6 +1968,7 @@ defmodule BlockScoutWeb.Etherscan do
   @contract_module %{
     name: "contract",
     actions: [
+      @contract_listcontracts_action,
       @contract_getabi_action,
       @contract_getsourcecode_action
     ]

apps/block_scout_web/lib/block_scout_web/templates/address_contract_verification/new.html.eex

@@ -29,7 +29,7 @@
 
         <div class="form-group">
           <%= label :evm_version, :evm_version, gettext("EVM Version") %>
-          <%= select :evm_version, :evm_version, @evm_versions, class: "form-control", selected: "byzantium", "aria-describedby": "evm-version-help-block" %>
+          <%= select :evm_version, :evm_version, @evm_versions, class: "form-control", selected: "petersburg", "aria-describedby": "evm-version-help-block" %>
         </div>
 
         <div class="form-group mb-4">

apps/block_scout_web/lib/block_scout_web/views/api/rpc/contract_view.ex

@@ -2,40 +2,88 @@ defmodule BlockScoutWeb.API.RPC.ContractView do
   use BlockScoutWeb, :view
 
   alias BlockScoutWeb.API.RPC.RPCView
+  alias Explorer.Chain.{Address, DecompiledSmartContract, SmartContract}
+
+  def render("listcontracts.json", %{contracts: contracts}) do
+    contracts = Enum.map(contracts, &prepare_contract/1)
+
+    RPCView.render("show.json", data: contracts)
+  end
 
   def render("getabi.json", %{abi: abi}) do
     RPCView.render("show.json", data: Jason.encode!(abi))
   end
 
-  def render("getsourcecode.json", %{contract: contract}) do
-    RPCView.render("show.json", data: prepare_contract(contract))
+  def render("getsourcecode.json", %{contract: contract, address_hash: address_hash}) do
+    RPCView.render("show.json", data: [prepare_source_code_contract(contract, address_hash)])
   end
 
   def render("error.json", assigns) do
     RPCView.render("error.json", assigns)
   end
 
-  defp prepare_contract(nil) do
-    [
+  defp prepare_source_code_contract(nil, address_hash) do
     %{
+      "Address" => to_string(address_hash),
       "SourceCode" => "",
       "ABI" => "Contract source code not verified",
       "ContractName" => "",
       "CompilerVersion" => "",
+      "DecompiledSourceCode" => "",
+      "DecompilerVersion" => "",
       "OptimizationUsed" => ""
     }
-    ]
   end
 
-  defp prepare_contract(contract) do
-    [
+  defp prepare_source_code_contract(contract, _) do
     %{
+      "Address" => to_string(contract.address_hash),
       "SourceCode" => contract.contract_source_code,
       "ABI" => Jason.encode!(contract.abi),
       "ContractName" => contract.name,
+      "DecompiledSourceCode" => decompiled_source_code(contract.decompiled_smart_contract),
+      "DecompilerVersion" => decompiler_version(contract.decompiled_smart_contract),
       "CompilerVersion" => contract.compiler_version,
       "OptimizationUsed" => if(contract.optimization, do: "1", else: "0")
     }
-    ]
   end
+
+  defp prepare_contract(%Address{hash: hash, smart_contract: nil, decompiled_smart_contract: decompiled_smart_contract}) do
+    %{
+      "Address" => to_string(hash),
+      "SourceCode" => "",
+      "ABI" => "Contract source code not verified",
+      "ContractName" => "",
+      "DecompiledSourceCode" => decompiled_source_code(decompiled_smart_contract),
+      "DecompilerVersion" => decompiler_version(decompiled_smart_contract),
+      "CompilerVersion" => "",
+      "OptimizationUsed" => ""
+    }
+  end
+
+  defp prepare_contract(%Address{
+         hash: hash,
+         smart_contract: %SmartContract{} = contract,
+         decompiled_smart_contract: decompiled_smart_contract
+       }) do
+    %{
+      "Address" => to_string(hash),
+      "SourceCode" => contract.contract_source_code,
+      "ABI" => Jason.encode!(contract.abi),
+      "ContractName" => contract.name,
+      "DecompiledSourceCode" => decompiled_source_code(decompiled_smart_contract),
+      "DecompilerVersion" => decompiler_version(decompiled_smart_contract),
+      "CompilerVersion" => contract.compiler_version,
+      "OptimizationUsed" => if(contract.optimization, do: "1", else: "0")
+    }
+  end
+
+  defp decompiled_source_code(nil), do: "Contract source code not decompiled."
+
+  defp decompiled_source_code(%DecompiledSmartContract{decompiled_source_code: decompiled_source_code}) do
+    decompiled_source_code
+  end
+
+  defp decompiler_version(nil), do: ""
+  defp decompiler_version(%DecompiledSmartContract{decompiler_version: decompiler_version}), do: decompiler_version
 end

apps/block_scout_web/test/block_scout_web/controllers/api/rpc/address_controller_test.exs

@@ -767,34 +767,7 @@ defmodule BlockScoutWeb.API.RPC.AddressControllerTest do
       assert response["message"] == "OK"
     end
 
-    test "ignores pagination params if page is less than 1", %{conn: conn} do
-      address = insert(:address)
-
-      6
-      |> insert_list(:transaction, from_address: address)
-      |> with_block()
-
-      params = %{
-        "module" => "account",
-        "action" => "txlist",
-        "address" => "#{address.hash}",
-        # page number
-        "page" => "0",
-        # page size
-        "offset" => "2"
-      }
-
-      assert response =
-               conn
-               |> get("/api", params)
-               |> json_response(200)
-
-      assert length(response["result"]) == 6
-      assert response["status"] == "1"
-      assert response["message"] == "OK"
-    end
-
-    test "ignores pagination params if offset is less than 1", %{conn: conn} do
+    test "ignores offset param if offset is less than 1", %{conn: conn} do
       address = insert(:address)
 
       6
@@ -821,7 +794,7 @@ defmodule BlockScoutWeb.API.RPC.AddressControllerTest do
       assert response["message"] == "OK"
     end
 
-    test "ignores pagination params if offset is over 10,000", %{conn: conn} do
+    test "ignores offset param if offset is over 10,000", %{conn: conn} do
       address = insert(:address)
 
       6

apps/block_scout_web/test/block_scout_web/controllers/api/rpc/contract_controller_test.exs

@@ -1,6 +1,190 @@
 defmodule BlockScoutWeb.API.RPC.ContractControllerTest do
   use BlockScoutWeb.ConnCase
 
+  describe "listcontracts" do
+    setup do
+      %{params: %{"module" => "contract", "action" => "listcontracts"}}
+    end
+
+    test "with an invalid filter value", %{conn: conn, params: params} do
+      response =
+        conn
+        |> get("/api", Map.put(params, "filter", "invalid"))
+        |> json_response(400)
+
+      assert response["message"] ==
+               "invalid is not a valid value for `filter`. Please use one of: verified, decompiled, unverified, not_decompiled, 1, 2, 3, 4."
+
+      assert response["status"] == "0"
+    end
+
+    test "with no contracts", %{conn: conn, params: params} do
+      response =
+        conn
+        |> get("/api", params)
+        |> json_response(200)
+
+      assert response["message"] == "OK"
+      assert response["status"] == "1"
+      assert response["result"] == []
+    end
+
+    test "with a verified smart contract, all contract information is shown", %{conn: conn, params: params} do
+      contract = insert(:smart_contract)
+
+      response =
+        conn
+        |> get("/api", params)
+        |> json_response(200)
+
+      assert response["message"] == "OK"
+      assert response["status"] == "1"
+
+      assert response["result"] == [
+               %{
+                 "ABI" => Jason.encode!(contract.abi),
+                 "Address" => to_string(contract.address_hash),
+                 "CompilerVersion" => contract.compiler_version,
+                 "ContractName" => contract.name,
+                 "DecompiledSourceCode" => "Contract source code not decompiled.",
+                 "DecompilerVersion" => "",
+                 "OptimizationUsed" => if(contract.optimization, do: "1", else: "0"),
+                 "SourceCode" => contract.contract_source_code
+               }
+             ]
+    end
+
+    test "with an unverified contract address, only basic information is shown", %{conn: conn, params: params} do
+      address = insert(:contract_address)
+
+      response =
+        conn
+        |> get("/api", params)
+        |> json_response(200)
+
+      assert response["message"] == "OK"
+      assert response["status"] == "1"
+
+      assert response["result"] == [
+               %{
+                 "ABI" => "Contract source code not verified",
+                 "Address" => to_string(address.hash),
+                 "CompilerVersion" => "",
+                 "ContractName" => "",
+                 "DecompiledSourceCode" => "Contract source code not decompiled.",
+                 "DecompilerVersion" => "",
+                 "OptimizationUsed" => "",
+                 "SourceCode" => ""
+               }
+             ]
+    end
+
+    test "filtering for only unverified contracts shows only unverified contracts", %{params: params, conn: conn} do
+      address = insert(:contract_address)
+      insert(:smart_contract)
+
+      response =
+        conn
+        |> get("/api", Map.put(params, "filter", "unverified"))
+        |> json_response(200)
+
+      assert response["message"] == "OK"
+      assert response["status"] == "1"
+
+      assert response["result"] == [
+               %{
+                 "ABI" => "Contract source code not verified",
+                 "Address" => to_string(address.hash),
+                 "CompilerVersion" => "",
+                 "ContractName" => "",
+                 "DecompiledSourceCode" => "Contract source code not decompiled.",
+                 "DecompilerVersion" => "",
+                 "OptimizationUsed" => "",
+                 "SourceCode" => ""
+               }
+             ]
+    end
+
+    test "filtering for only verified contracts shows only verified contracts", %{params: params, conn: conn} do
+      insert(:contract_address)
+      contract = insert(:smart_contract)
+
+      response =
+        conn
+        |> get("/api", Map.put(params, "filter", "verified"))
+        |> json_response(200)
+
+      assert response["message"] == "OK"
+      assert response["status"] == "1"
+
+      assert response["result"] == [
+               %{
+                 "ABI" => Jason.encode!(contract.abi),
+                 "Address" => to_string(contract.address_hash),
+                 "CompilerVersion" => contract.compiler_version,
+                 "DecompiledSourceCode" => "Contract source code not decompiled.",
+                 "DecompilerVersion" => "",
+                 "ContractName" => contract.name,
+                 "OptimizationUsed" => if(contract.optimization, do: "1", else: "0"),
+                 "SourceCode" => contract.contract_source_code
+               }
+             ]
+    end
+
+    test "filtering for only decompiled contracts shows only decompiled contracts", %{params: params, conn: conn} do
+      insert(:contract_address)
+      decompiled_smart_contract = insert(:decompiled_smart_contract)
+
+      response =
+        conn
+        |> get("/api", Map.put(params, "filter", "decompiled"))
+        |> json_response(200)
+
+      assert response["message"] == "OK"
+      assert response["status"] == "1"
+
+      assert response["result"] == [
+               %{
+                 "ABI" => "Contract source code not verified",
+                 "Address" => to_string(decompiled_smart_contract.address_hash),
+                 "CompilerVersion" => "",
+                 "ContractName" => "",
+                 "DecompiledSourceCode" => decompiled_smart_contract.decompiled_source_code,
+                 "DecompilerVersion" => "test_decompiler",
+                 "OptimizationUsed" => "",
+                 "SourceCode" => ""
+               }
+             ]
+    end
+
+    test "filtering for only not_decompiled (and by extension not verified contracts)", %{params: params, conn: conn} do
+      insert(:decompiled_smart_contract)
+      insert(:smart_contract)
+      contract_address = insert(:contract_address)
+
+      response =
+        conn
+        |> get("/api", Map.put(params, "filter", "not_decompiled"))
+        |> json_response(200)
+
+      assert response["message"] == "OK"
+      assert response["status"] == "1"
+
+      assert response["result"] == [
+               %{
+                 "ABI" => "Contract source code not verified",
+                 "Address" => to_string(contract_address.hash),
+                 "CompilerVersion" => "",
+                 "ContractName" => "",
+                 "DecompiledSourceCode" => "Contract source code not decompiled.",
+                 "DecompilerVersion" => "",
+                 "OptimizationUsed" => "",
+                 "SourceCode" => ""
+               }
+             ]
+    end
+  end
+
   describe "getabi" do
     test "with missing address hash", %{conn: conn} do
       params = %{
@@ -119,11 +303,14 @@ defmodule BlockScoutWeb.API.RPC.ContractControllerTest do
 
       expected_result = [
         %{
+          "Address" => "",
           "SourceCode" => "",
           "ABI" => "Contract source code not verified",
           "ContractName" => "",
           "CompilerVersion" => "",
-          "OptimizationUsed" => ""
+          "OptimizationUsed" => "",
+          "DecompiledSourceCode" => "",
+          "DecompilerVersion" => ""
         }
       ]
 
@@ -148,13 +335,16 @@ defmodule BlockScoutWeb.API.RPC.ContractControllerTest do
 
       expected_result = [
         %{
+          "Address" => to_string(contract.address_hash),
           "SourceCode" => contract.contract_source_code,
           "ABI" => Jason.encode!(contract.abi),
           "ContractName" => contract.name,
           "CompilerVersion" => contract.compiler_version,
+          "DecompiledSourceCode" => "Contract source code not decompiled.",
           # The contract's optimization value is true, so the expected value
           # for `OptimizationUsed` is "1". If it was false, the expected value
           # would be "0".
+          "DecompilerVersion" => "",
           "OptimizationUsed" => "1"
         }
       ]

apps/block_scout_web/test/block_scout_web/features/address_contract_verification_test.exs

@@ -36,7 +36,8 @@ defmodule BlockScoutWeb.AddressContractVerificationTest do
       contract_name: name,
       version: version,
       optimization: false,
-      source_code: source_code
+      source_code: source_code,
+      evm_version: "byzantium"
     })
     |> ContractVerifyPage.verify_and_publish()
 

apps/block_scout_web/test/block_scout_web/features/pages/contract_verify_page.ex

@@ -13,7 +13,8 @@ defmodule BlockScoutWeb.ContractVerifyPage do
         contract_name: contract_name,
         version: version,
         optimization: optimization,
-        source_code: source_code
+        source_code: source_code,
+        evm_version: evm_version
       }) do
     session
     |> fill_in(css("[data-test='contract_name']"), with: contract_name)
@@ -24,6 +25,11 @@ defmodule BlockScoutWeb.ContractVerifyPage do
       _ -> click(session, option(version))
     end
 
+    case evm_version do
+      nil -> nil
+      _ -> click(session, option(evm_version))
+    end
+
     case optimization do
       true ->
         click(session, radio_button("Yes"))

apps/explorer/lib/explorer/application.ex

@@ -6,7 +6,7 @@ defmodule Explorer.Application do
   use Application
 
   alias Explorer.Admin
-  alias Explorer.Chain.BlockNumberCache
+  alias Explorer.Chain.{BlockNumberCache, TransactionCountCache}
   alias Explorer.Repo.PrometheusLogger
 
   @impl Application
@@ -27,7 +27,8 @@ defmodule Explorer.Application do
       Supervisor.child_spec({Task.Supervisor, name: Explorer.MarketTaskSupervisor}, id: Explorer.MarketTaskSupervisor),
       Supervisor.child_spec({Task.Supervisor, name: Explorer.TaskSupervisor}, id: Explorer.TaskSupervisor),
       {Registry, keys: :duplicate, name: Registry.ChainEvents, id: Registry.ChainEvents},
-      {Admin.Recovery, [[], [name: Admin.Recovery]]}
+      {Admin.Recovery, [[], [name: Admin.Recovery]]},
+      {TransactionCountCache, [[], []]}
     ]
 
     children = base_children ++ configurable_children()

apps/explorer/lib/explorer/chain.ex

@@ -20,7 +20,6 @@ defmodule Explorer.Chain do
 
   import EthereumJSONRPC, only: [integer_to_quantity: 1]
 
-  alias Ecto.Adapters.SQL
   alias Ecto.{Changeset, Multi}
 
   alias Explorer.Chain.{
@@ -40,6 +39,7 @@ defmodule Explorer.Chain do
     Token,
     TokenTransfer,
     Transaction,
+    TransactionCountCache,
     Wei
   }
 
@@ -1868,10 +1868,7 @@ defmodule Explorer.Chain do
   """
   @spec transaction_estimated_count() :: non_neg_integer()
   def transaction_estimated_count do
-    %Postgrex.Result{rows: [[rows]]} =
-      SQL.query!(Repo, "SELECT reltuples::BIGINT AS estimate FROM pg_class WHERE relname='transactions'")
-
-    rows
+    TransactionCountCache.value()
   end
 
   @doc """
@@ -2629,6 +2626,88 @@ defmodule Explorer.Chain do
     Repo.all(query, timeout: :infinity)
   end
 
+  def list_decompiled_contracts(limit, offset) do
+    query =
+      from(
+        address in Address,
+        join: decompiled_smart_contract in DecompiledSmartContract,
+        on: decompiled_smart_contract.address_hash == address.hash,
+        preload: [{:decompiled_smart_contract, decompiled_smart_contract}, :smart_contract],
+        order_by: [asc: address.inserted_at],
+        limit: ^limit,
+        offset: ^offset
+      )
+
+    Repo.all(query)
+  end
+
+  def list_verified_contracts(limit, offset) do
+    query =
+      from(
+        address in Address,
+        where: not is_nil(address.contract_code),
+        join: smart_contract in SmartContract,
+        on: smart_contract.address_hash == address.hash,
+        preload: [{:smart_contract, smart_contract}, :decompiled_smart_contract],
+        order_by: [asc: address.inserted_at],
+        limit: ^limit,
+        offset: ^offset
+      )
+
+    Repo.all(query)
+  end
+
+  def list_contracts(limit, offset) do
+    query =
+      from(
+        address in Address,
+        where: not is_nil(address.contract_code),
+        preload: [:smart_contract, :decompiled_smart_contract],
+        order_by: [asc: address.inserted_at],
+        limit: ^limit,
+        offset: ^offset
+      )
+
+    Repo.all(query)
+  end
+
+  def list_unverified_contracts(limit, offset) do
+    query =
+      from(
+        address in Address,
+        left_join: smart_contract in SmartContract,
+        on: smart_contract.address_hash == address.hash,
+        where: not is_nil(address.contract_code),
+        where: is_nil(smart_contract.address_hash),
+        preload: [{:smart_contract, smart_contract}, :decompiled_smart_contract],
+        order_by: [asc: address.inserted_at],
+        limit: ^limit,
+        offset: ^offset
+      )
+
+    Repo.all(query)
+  end
+
+  def list_not_decompiled_contracts(limit, offset) do
+    query =
+      from(
+        address in Address,
+        left_join: smart_contract in SmartContract,
+        on: smart_contract.address_hash == address.hash,
+        left_join: decompiled_smart_contract in DecompiledSmartContract,
+        on: decompiled_smart_contract.address_hash == address.hash,
+        preload: [smart_contract: smart_contract, decompiled_smart_contract: decompiled_smart_contract],
+        where: not is_nil(address.contract_code),
+        where: is_nil(smart_contract.address_hash),
+        where: is_nil(decompiled_smart_contract.address_hash),
+        order_by: [asc: address.inserted_at],
+        limit: ^limit,
+        offset: ^offset
+      )
+
+    Repo.all(query)
+  end
+
   @doc """
   Combined block reward from all the fees.
   """

apps/explorer/lib/explorer/chain/address.ex

@@ -8,7 +8,19 @@ defmodule Explorer.Chain.Address do
   use Explorer.Schema
 
   alias Ecto.Changeset
-  alias Explorer.Chain.{Address, Block, Data, Hash, InternalTransaction, SmartContract, Token, Transaction, Wei}
+
+  alias Explorer.Chain.{
+    Address,
+    Block,
+    Data,
+    DecompiledSmartContract,
+    Hash,
+    InternalTransaction,
+    SmartContract,
+    Token,
+    Transaction,
+    Wei
+  }
 
   @optional_attrs ~w(contract_code fetched_coin_balance fetched_coin_balance_block_number nonce)a
   @required_attrs ~w(hash)a
@@ -64,6 +76,7 @@ defmodule Explorer.Chain.Address do
     field(:nonce, :integer)
 
     has_one(:smart_contract, SmartContract)
+    has_one(:decompiled_smart_contract, DecompiledSmartContract)
     has_one(:token, Token, foreign_key: :contract_address_hash)
 
     has_one(

apps/explorer/lib/explorer/chain/import/runner/blocks.ex

@@ -46,6 +46,7 @@ defmodule Explorer.Chain.Import.Runner.Blocks do
       |> Map.put(:timestamps, timestamps)
 
     ordered_consensus_block_numbers = ordered_consensus_block_numbers(changes_list)
+    where_invalid_parent = where_invalid_parent(changes_list)
     where_forked = where_forked(changes_list)
 
     multi
@@ -69,6 +70,9 @@ defmodule Explorer.Chain.Import.Runner.Blocks do
     |> Multi.run(:lose_consensus, fn repo, _ ->
       lose_consensus(repo, ordered_consensus_block_numbers, insert_options)
     end)
+    |> Multi.run(:lose_invalid_parent_consensus, fn repo, _ ->
+      lose_invalid_parent_consensus(repo, where_invalid_parent, insert_options)
+    end)
     |> Multi.run(:delete_address_token_balances, fn repo, _ ->
       delete_address_token_balances(repo, ordered_consensus_block_numbers, insert_options)
     end)
@@ -312,6 +316,32 @@ defmodule Explorer.Chain.Import.Runner.Blocks do
     end
   end
 
+  defp lose_invalid_parent_consensus(repo, where_invalid_parent, %{
+         timeout: timeout,
+         timestamps: %{updated_at: updated_at}
+       }) do
+    query =
+      from(
+        block in where_invalid_parent,
+        update: [
+          set: [
+            consensus: false,
+            updated_at: ^updated_at
+          ]
+        ],
+        select: [:hash, :number]
+      )
+
+    try do
+      {_, result} = repo.update_all(query, [], timeout: timeout)
+
+      {:ok, result}
+    rescue
+      postgrex_error in Postgrex.Error ->
+        {:error, %{exception: postgrex_error, where_invalid_parent: where_invalid_parent}}
+    end
+  end
+
   defp delete_address_token_balances(_, [], _), do: {:ok, []}
 
   defp delete_address_token_balances(repo, ordered_consensus_block_numbers, %{timeout: timeout}) do
@@ -543,12 +573,22 @@ defmodule Explorer.Chain.Import.Runner.Blocks do
     initial = from(t in Transaction, where: false)
 
     Enum.reduce(blocks_changes, initial, fn %{consensus: consensus, hash: hash, number: number}, acc ->
-      case consensus do
-        false ->
+      if consensus do
+        from(transaction in acc, or_where: transaction.block_hash != ^hash and transaction.block_number == ^number)
+      else
         from(transaction in acc, or_where: transaction.block_hash == ^hash and transaction.block_number == ^number)
+      end
+    end)
+  end
 
-        true ->
-          from(transaction in acc, or_where: transaction.block_hash != ^hash and transaction.block_number == ^number)
+  defp where_invalid_parent(blocks_changes) when is_list(blocks_changes) do
+    initial = from(b in Block, where: false)
+
+    Enum.reduce(blocks_changes, initial, fn %{consensus: consensus, parent_hash: parent_hash, number: number}, acc ->
+      if consensus do
+        from(block in acc, or_where: block.number == ^(number - 1) and block.hash != ^parent_hash)
+      else
+        acc
       end
     end)
   end

apps/explorer/lib/explorer/chain/smart_contract.ex

@@ -12,7 +12,8 @@ defmodule Explorer.Chain.SmartContract do
 
   use Explorer.Schema
 
-  alias Explorer.Chain.{Address, ContractMethod, Hash}
+  alias Explorer.Chain.{Address, ContractMethod, DecompiledSmartContract, Hash}
+  alias Explorer.Repo
 
   @typedoc """
   The name of a parameter to a function or event.
@@ -208,6 +209,12 @@ defmodule Explorer.Chain.SmartContract do
     field(:constructor_arguments, :string)
     field(:abi, {:array, :map})
 
+    has_one(
+      :decompiled_smart_contract,
+      DecompiledSmartContract,
+      foreign_key: :address_hash
+    )
+
     belongs_to(
       :address,
       Address,
@@ -219,6 +226,10 @@ defmodule Explorer.Chain.SmartContract do
     timestamps()
   end
 
+  def preload_decompiled_smart_contract(contract) do
+    Repo.preload(contract, :decompiled_smart_contract)
+  end
+
   def changeset(%__MODULE__{} = smart_contract, attrs) do
     smart_contract
     |> cast(attrs, [

apps/explorer/lib/explorer/chain/transaction_count_cache.ex

@@ -0,0 +1,154 @@
+defmodule Explorer.Chain.TransactionCountCache do
+  @moduledoc """
+  Cache for estimated transaction count.
+  """
+
+  require Logger
+
+  use GenServer
+
+  alias Explorer.Chain.Transaction
+  alias Explorer.Repo
+
+  # 2 hours
+  @cache_period 1_000 * 60 * 60 * 2
+  @default_value 0
+  @key "count"
+  @name __MODULE__
+
+  def start_link([params, gen_server_options]) do
+    name = gen_server_options[:name] || @name
+    params_with_name = Keyword.put(params, :name, name)
+
+    GenServer.start_link(__MODULE__, params_with_name, name: name)
+  end
+
+  def init(params) do
+    cache_period = period_from_env_var() || params[:cache_period] || @cache_period
+    current_value = params[:default_value] || @default_value
+    name = params[:name]
+
+    init_ets_table(name)
+
+    schedule_cache_update()
+
+    {:ok, {{cache_period, current_value, name}, nil}}
+  end
+
+  def value(process_name \\ __MODULE__) do
+    GenServer.call(process_name, :value)
+  end
+
+  def handle_call(:value, _, {{cache_period, default_value, name}, task}) do
+    {value, task} =
+      case cached_values(name) do
+        nil ->
+          {default_value, update_cache(task, name)}
+
+        {cached_value, timestamp} ->
+          task =
+            if current_time() - timestamp > cache_period do
+              update_cache(task, name)
+            end
+
+          {cached_value, task}
+      end
+
+    {:reply, value, {{cache_period, default_value, name}, task}}
+  end
+
+  def update_cache(nil, name) do
+    async_update_cache(name)
+  end
+
+  def update_cache(task, _) do
+    task
+  end
+
+  def handle_cast({:update_cache, value}, {{cache_period, default_value, name}, _}) do
+    current_time = current_time()
+    tuple = {value, current_time}
+
+    table_name = table_name(name)
+
+    :ets.insert(table_name, {@key, tuple})
+
+    {:noreply, {{cache_period, default_value, name}, nil}}
+  end
+
+  def handle_info({:DOWN, _, _, _, _}, {{cache_period, default_value, name}, _}) do
+    {:noreply, {{cache_period, default_value, name}, nil}}
+  end
+
+  def handle_info(_, {{cache_period, default_value, name}, _}) do
+    {:noreply, {{cache_period, default_value, name}, nil}}
+  end
+
+  # sobelow_skip ["DOS"]
+  defp table_name(name) do
+    name
+    |> Atom.to_string()
+    |> Macro.underscore()
+    |> String.to_atom()
+  end
+
+  def async_update_cache(name) do
+    Task.async(fn ->
+      try do
+        result = Repo.aggregate(Transaction, :count, :hash, timeout: :infinity)
+
+        GenServer.cast(name, {:update_cache, result})
+      rescue
+        e ->
+          Logger.debug([
+            "Coudn't update transaction count test #{inspect(e)}"
+          ])
+      end
+    end)
+  end
+
+  defp init_ets_table(name) do
+    table_name = table_name(name)
+
+    if :ets.whereis(table_name) == :undefined do
+      :ets.new(table_name, [
+        :set,
+        :named_table,
+        :public,
+        write_concurrency: true
+      ])
+    end
+  end
+
+  defp cached_values(name) do
+    table_name = table_name(name)
+
+    case :ets.lookup(table_name, @key) do
+      [{_, cached_values}] -> cached_values
+      _ -> nil
+    end
+  end
+
+  defp schedule_cache_update do
+    Process.send_after(self(), :update_cache, 2_000)
+  end
+
+  defp current_time do
+    utc_now = DateTime.utc_now()
+
+    DateTime.to_unix(utc_now, :millisecond)
+  end
+
+  defp period_from_env_var do
+    case System.get_env("TXS_COUNT_CACHE_PERIOD") do
+      value when is_binary(value) ->
+        case Integer.parse(value) do
+          {integer, ""} -> integer * 1_000 * 60 * 60
+          _ -> nil
+        end
+
+      _ ->
+        nil
+    end
+  end
+end

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

@@ -4,7 +4,7 @@ defmodule Explorer.SmartContract.Solidity.CodeCompiler do
   """
 
   @new_contract_name "New.sol"
-  @allowed_evm_versions ["homestead", "tangerineWhistle", "spuriousDragon", "byzantium", "constantinople"]
+  @allowed_evm_versions ["homestead", "tangerineWhistle", "spuriousDragon", "byzantium", "constantinople", "petersburg"]
 
   @doc """
   Compiles a code in the solidity command line.
@@ -98,6 +98,8 @@ defmodule Explorer.SmartContract.Solidity.CodeCompiler do
     end
   end
 
+  def allowed_evm_versions, do: @allowed_evm_versions
+
   def get_contract_info(contracts, _) when contracts == %{}, do: {:error, :compilation}
 
   def get_contract_info(contracts, name) do

apps/explorer/priv/repo/migrations/scripts/20190326202921_lose_consensus_for_invalid_blocks.sql

@@ -0,0 +1,6 @@
+UPDATE blocks SET consensus = FALSE, updated_at = NOW()
+WHERE consensus AND number IN (
+  SELECT b0.number - 1 FROM "blocks" AS b0
+  LEFT JOIN "blocks" AS b1 ON (b0."parent_hash" = b1."hash") AND b1."consensus"
+  WHERE b0."number" > 0 AND b0."consensus" AND b1."hash" IS NULL
+);

apps/explorer/test/explorer/chain/import/runner/blocks_test.exs

@@ -8,6 +8,7 @@ defmodule Explorer.Chain.Import.Runner.BlocksTest do
   alias Ecto.Multi
   alias Explorer.Chain.Import.Runner.{Blocks, Transaction}
   alias Explorer.Chain.{Address, Block, Transaction}
+  alias Explorer.Chain
   alias Explorer.Repo
 
   describe "run/1" do
@@ -258,6 +259,36 @@ defmodule Explorer.Chain.Import.Runner.BlocksTest do
                 blocks_update_token_holder_counts: []
               }} = run_block_consensus_change(block, true, options)
     end
+
+    # Regression test for https://github.com/poanetwork/blockscout/issues/1644
+    test "discards parent block if it isn't related to the current one because of reorg",
+         %{consensus_block: %Block{number: block_number, hash: block_hash, miner_hash: miner_hash}, options: options} do
+      old_block = insert(:block, parent_hash: block_hash, number: block_number + 1)
+      insert(:block, parent_hash: old_block.hash, number: old_block.number + 1)
+
+      new_block1 = params_for(:block, parent_hash: block_hash, number: block_number + 1, miner_hash: miner_hash)
+
+      new_block2 =
+        params_for(:block, parent_hash: new_block1.hash, number: new_block1.number + 1, miner_hash: miner_hash)
+
+      %Ecto.Changeset{valid?: true, changes: block_changes} = Block.changeset(%Block{}, new_block2)
+      changes_list = [block_changes]
+
+      Multi.new()
+      |> Blocks.run(changes_list, options)
+      |> Repo.transaction()
+
+      assert Chain.missing_block_number_ranges(block_number..new_block2.number) == [old_block.number..old_block.number]
+
+      %Ecto.Changeset{valid?: true, changes: block_changes} = Block.changeset(%Block{}, new_block1)
+      changes_list = [block_changes]
+
+      Multi.new()
+      |> Blocks.run(changes_list, options)
+      |> Repo.transaction()
+
+      assert Chain.missing_block_number_ranges(block_number..new_block2.number) == []
+    end
   end
 
   defp count(schema) do

apps/explorer/test/explorer/chain/transaction_count_cache_test.exs

@@ -0,0 +1,54 @@
+defmodule Explorer.Chain.TransactionCountCacheTest do
+  use Explorer.DataCase
+
+  alias Explorer.Chain.TransactionCountCache
+
+  test "returns default transaction count" do
+    TransactionCountCache.start_link([[], [name: TestCache]])
+
+    result = TransactionCountCache.value(TestCache)
+
+    assert result == 0
+  end
+
+  test "updates cache if initial value is zero" do
+    TransactionCountCache.start_link([[], [name: TestCache]])
+
+    insert(:transaction)
+    insert(:transaction)
+
+    _result = TransactionCountCache.value(TestCache)
+
+    Process.sleep(1000)
+
+    updated_value = TransactionCountCache.value(TestCache)
+
+    assert updated_value == 2
+  end
+
+  test "does not update cache if cache period did not pass" do
+    TransactionCountCache.start_link([[], [name: TestCache]])
+
+    insert(:transaction)
+    insert(:transaction)
+
+    _result = TransactionCountCache.value(TestCache)
+
+    Process.sleep(1000)
+
+    updated_value = TransactionCountCache.value(TestCache)
+
+    assert updated_value == 2
+
+    insert(:transaction)
+    insert(:transaction)
+
+    _updated_value = TransactionCountCache.value(TestCache)
+
+    Process.sleep(1000)
+
+    updated_value = TransactionCountCache.value(TestCache)
+
+    assert updated_value == 2
+  end
+end