make tab visible if contract has any decompiled code

apps/block_scout_web/lib/block_scout_web/templates/address/_tabs.html.eex

@@ -57,6 +57,16 @@
         <% end %>
       <% end %>
     </li>
+
+    <%= if @address.has_decompiled_code? do %>
+      <li class="nav-item">
+        <%= link(
+            to: address_contract_path(@conn, :index, @address.hash),
+            class: "nav-link #{tab_status("contracts", @conn.request_path)}") do %>
+           <%= gettext("Decompiled code") %>
+        <% end %>
+      </li>
+    <% end %>
   <% end %>
 
   <%= if smart_contract_with_read_only_functions?(@address) do %>

apps/explorer/lib/explorer/chain.ex

@@ -647,9 +647,17 @@ defmodule Explorer.Chain do
   """
   @spec hash_to_address(Hash.Address.t()) :: {:ok, Address.t()} | {:error, :not_found}
   def hash_to_address(%Hash{byte_count: unquote(Hash.Address.byte_count())} = hash) do
+    has_decompiled_code_query =
+      from(decompiled_contract in DecompiledSmartContract,
+        where: decompiled_contract.address_hash == ^hash,
+        limit: 1,
+        select: %{has_decompiled_code?: not is_nil(decompiled_contract.address_hash)}
+      )
+
     query =
       from(
         address in Address,
+        left_join: decompiled_code in subquery(has_decompiled_code_query),
         preload: [
           :contracts_creation_internal_transaction,
           :names,
@@ -657,7 +665,8 @@ defmodule Explorer.Chain do
           :token,
           :contracts_creation_transaction
         ],
-        where: address.hash == ^hash
+        where: address.hash == ^hash,
+        select_merge: %{has_decompiled_code?: decompiled_code.has_decompiled_code?}
       )
 
     query

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
@@ -62,6 +74,7 @@ defmodule Explorer.Chain.Address do
     field(:fetched_coin_balance_block_number, :integer)
     field(:contract_code, Data)
     field(:nonce, :integer)
+    field(:has_decompiled_code?, :boolean, virtual: true)
 
     has_one(:smart_contract, SmartContract)
     has_one(:token, Token, foreign_key: :contract_address_hash)
@@ -79,6 +92,7 @@ defmodule Explorer.Chain.Address do
     )
 
     has_many(:names, Address.Name, foreign_key: :address_hash)
+    has_many(:decompiled_smart_contract, DecompiledSmartContract, foreign_key: :address_hash)
 
     timestamps()
   end

apps/explorer/test/explorer/chain_test.exs

@@ -854,6 +854,23 @@ defmodule Explorer.ChainTest do
 
       assert {:ok, address} = Chain.hash_to_address(address.hash)
     end
+
+    test "has_decompiled_code? is true if there are decompiled contracts" do
+      address = insert(:address)
+      insert(:decompiled_smart_contract, address_hash: address.hash)
+
+      {:ok, found_address} = Chain.hash_to_address(address.hash)
+
+      assert found_address.has_decompiled_code?
+    end
+
+    test "has_decompiled_code? is false if there are no decompiled contracts" do
+      address = insert(:address)
+
+      {:ok, found_address} = Chain.hash_to_address(address.hash)
+
+      refute found_address.has_decompiled_code?
+    end
   end
 
   describe "token_contract_address_from_token_name/1" do