Fetch unremovable staking and disallow staking to empty pool (#2608)

is_unremovable field is added to staking pools and filled using contract
getter unremovableValidator.
If such validator hasn't staked to itself yet, Stake button is disabled.
Also, Remove My Pool button is disabled for such validator.

Also, fetching is_validator field is optimized, and is now performed using
one getValidators call instead of one isValidator call per pool.

apps/block_scout_web/lib/block_scout_web/controllers/stakes_controller.ex

@@ -92,7 +92,7 @@ defmodule BlockScoutWeb.StakesController do
           average_block_time: average_block_time,
           pools_type: filter,
           buttons: %{
-            stake: true,
+            stake: stake_allowed?(pool, delegator),
             move: move_allowed?(delegator),
             withdraw: withdraw_allowed?(delegator, epoch_number)
           }
@@ -130,6 +130,14 @@ defmodule BlockScoutWeb.StakesController do
     inactive_pools_path(conn, :index, params)
   end
 
+  defp stake_allowed?(pool, nil) do
+    Decimal.positive?(pool.self_staked_amount)
+  end
+
+  defp stake_allowed?(pool, delegator) do
+    Decimal.positive?(pool.self_staked_amount) or delegator.delegator_address_hash == pool.staking_address_hash
+  end
+
   defp move_allowed?(nil), do: false
 
   defp move_allowed?(delegator) do

apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_modal_move.html.eex

@@ -26,7 +26,9 @@
               <div class="input-group form-group">
                 <select pool-select class="form-control">
                   <option disabled <%= unless @pool_to do "selected" end %>><%= gettext("Choose Pool") %></option>
-                  <%= for %{pool: pool} <- @pools, pool.staking_address_hash != @pool_from.staking_address_hash do %>
+                  <%= for %{pool: pool} <- @pools,
+                        pool.staking_address_hash != @pool_from.staking_address_hash,
+                        Decimal.positive?(pool.self_staked_amount) or pool.staking_address_hash == @delegator.delegator_address_hash do %>
                     <option
                       value="<%= pool.staking_address_hash %>"
                       <%= if @pool_to && pool.staking_address_hash == @pool_to.staking_address_hash do "selected" end %>

apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_top.html.eex

@@ -8,7 +8,9 @@
       <!-- Buttons -->
       <div class="stakes-top-buttons">
         <%= if @account[:pool] && @account.pool.is_active do %>
+          <%= unless @account.pool.is_unremovable do %>
             <%= render BlockScoutWeb.StakesView, "_stakes_btn_remove_pool.html", text: gettext("Remove My Pool"), extra_class: "js-remove-pool" %>
+          <% end %>
         <% else %>
           <%= render BlockScoutWeb.CommonComponentsView, "_btn_add_full.html", text: gettext("Become a Candidate"), extra_class: "js-become-candidate" %>
         <% end %>

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

@@ -127,6 +127,7 @@ defmodule Explorer.Chain.Import.Runner.StakingPools do
           is_active: fragment("EXCLUDED.is_active"),
           is_banned: fragment("EXCLUDED.is_banned"),
           is_validator: fragment("EXCLUDED.is_validator"),
+          is_unremovable: fragment("EXCLUDED.is_unremovable"),
           likelihood: fragment("EXCLUDED.likelihood"),
           block_reward_ratio: fragment("EXCLUDED.block_reward_ratio"),
           staked_ratio: fragment("EXCLUDED.staked_ratio"),

apps/explorer/lib/explorer/chain/staking_pool.ex

@@ -20,6 +20,7 @@ defmodule Explorer.Chain.StakingPool do
           is_active: boolean,
           is_banned: boolean,
           is_validator: boolean,
+          is_unremovable: boolean,
           likelihood: Decimal.t(),
           block_reward_ratio: Decimal.t(),
           staked_ratio: Decimal.t(),
@@ -34,11 +35,12 @@ defmodule Explorer.Chain.StakingPool do
     is_active delegators_count staked_amount self_staked_amount is_validator
     was_validator_count is_banned was_banned_count banned_until likelihood
     staked_ratio staking_address_hash mining_address_hash block_reward_ratio
+    is_unremovable
   )a
   @req_attrs ~w(
     is_active delegators_count staked_amount self_staked_amount is_validator
     was_validator_count is_banned was_banned_count banned_until
-    staking_address_hash mining_address_hash
+    staking_address_hash mining_address_hash is_unremovable
   )a
 
   schema "staking_pools" do
@@ -47,6 +49,7 @@ defmodule Explorer.Chain.StakingPool do
     field(:is_active, :boolean, default: false)
     field(:is_banned, :boolean, default: false)
     field(:is_validator, :boolean, default: false)
+    field(:is_unremovable, :boolean, default: false)
     field(:likelihood, :decimal)
     field(:block_reward_ratio, :decimal)
     field(:staked_ratio, :decimal)

apps/explorer/lib/explorer/staking/contract_reader.ex

@@ -17,7 +17,8 @@ defmodule Explorer.Staking.ContractReader do
       inactive_pools: {:staking, "getPoolsInactive", []},
       pools_likely: {:staking, "getPoolsToBeElected", []},
       pools_likelihood: {:staking, "getPoolsLikelihood", []},
-      validators: {:validator_set, "getValidators", []}
+      validators: {:validator_set, "getValidators", []},
+      unremovable_validator: {:validator_set, "unremovableValidator", []}
     ]
   end
 
@@ -37,7 +38,6 @@ defmodule Explorer.Staking.ContractReader do
 
   def pool_mining_requests(mining_address) do
     [
-      is_validator: {:validator_set, "isValidator", [mining_address]},
       was_validator_count: {:validator_set, "validatorCounter", [mining_address]},
       is_banned: {:validator_set, "isValidatorBanned", [mining_address]},
       banned_until: {:validator_set, "bannedUntil", [mining_address]},

apps/explorer/lib/explorer/staking/contract_state.ex

@@ -128,6 +128,8 @@ defmodule Explorer.Staking.ContractState do
     :ets.insert(@table_name, settings)
 
     pools = global_responses.active_pools ++ global_responses.inactive_pools
+    is_validator = Enum.into(global_responses.validators, %{}, &{hash_to_string(&1), true})
+    unremovable_validator = global_responses.unremovable_validator
 
     pool_staking_responses =
       pools
@@ -179,7 +181,9 @@ defmodule Explorer.Staking.ContractState do
             end,
           likelihood: ratio(likelihood[staking_address] || 0, total_likelihood),
           block_reward_ratio: staking_response.block_reward / 10_000,
-          is_deleted: false
+          is_deleted: false,
+          is_validator: is_validator[staking_response.mining_address_hash] || false,
+          is_unremovable: hash_to_string(staking_address) == unremovable_validator
         }
         |> Map.merge(
           Map.take(staking_response, [
@@ -191,7 +195,6 @@ defmodule Explorer.Staking.ContractState do
         )
         |> Map.merge(
           Map.take(mining_response, [
-            :is_validator,
             :was_validator_count,
             :is_banned,
             :banned_until,
@@ -203,10 +206,9 @@ defmodule Explorer.Staking.ContractState do
     delegator_entries =
       Enum.map(delegator_responses, fn {{pool_address, delegator_address, is_active}, response} ->
         staking_response = pool_staking_responses[pool_address]
-        mining_response = pool_mining_responses[pool_address]
 
         reward_ratio =
-          if mining_response.is_validator do
+          if is_validator[staking_response.mining_address_hash] do
             reward_ratio = delegator_rewards[pool_address][delegator_address]
 
             if reward_ratio do
@@ -304,6 +306,8 @@ defmodule Explorer.Staking.ContractState do
   defp ratio(_numerator, 0), do: 0
   defp ratio(numerator, denominator), do: numerator / denominator * 100
 
+  defp hash_to_string(hash), do: "0x" <> Base.encode16(hash, case: :lower)
+
   # sobelow_skip ["Traversal"]
   defp abi(file_name) do
     :explorer

apps/explorer/priv/repo/migrations/20190820212841_add_unremovable_to_staking_pools.exs

@@ -0,0 +1,9 @@
+defmodule Explorer.Repo.Migrations.AddUnremovableToStakingPools do
+  use Ecto.Migration
+
+  def change do
+    alter table(:staking_pools) do
+      add(:is_unremovable, :boolean, default: false, null: false)
+    end
+  end
+end

apps/explorer/test/explorer/staking/contract_state_test.exs

@@ -76,7 +76,7 @@ defmodule Explorer.Staking.ContractStateTest do
       EthereumJSONRPC.Mox,
       :json_rpc,
       fn requests, _opts ->
-        assert length(requests) == 11
+        assert length(requests) == 12
 
         {:ok,
          format_responses([
@@ -90,7 +90,8 @@ defmodule Explorer.Staking.ContractStateTest do
            "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000001000000000000000000000000b6695f5c2e3f5eff8036b5f5f3a9d83a5310e51e",
            "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002000000000000000000000000b916e7e1f4bcb13549602ed042d36746fd0d96c9000000000000000000000000db9cb2478d917719c53862008672166808258577",
            "0x00000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000514000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000c8000000000000000000000000000000000000000000000000000000000000044c",
-           "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000003000000000000000000000000bbcaa8d48289bb1ffcf9808d9aa4b1d215054c78000000000000000000000000f67cc5231c5858ad6cc87b105217426e17b824bb000000000000000000000000be69eb0968226a1808975e1a1f2127667f2bffb3"
+           "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000003000000000000000000000000bbcaa8d48289bb1ffcf9808d9aa4b1d215054c78000000000000000000000000f67cc5231c5858ad6cc87b105217426e17b824bb000000000000000000000000be69eb0968226a1808975e1a1f2127667f2bffb3",
+           "0x0000000000000000000000000b2f5e2f3cbd864eaa2c642e3769c1582361caf6"
          ])}
       end
     )
@@ -147,26 +148,22 @@ defmodule Explorer.Staking.ContractStateTest do
       EthereumJSONRPC.Mox,
       :json_rpc,
       fn requests, _opts ->
-        assert length(requests) == 20
+        assert length(requests) == 16
 
         {:ok,
          format_responses([
-           "0x0000000000000000000000000000000000000000000000000000000000000001",
            "0x000000000000000000000000000000000000000000000000000000000000004b",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
-           "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000002",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
-           "0x0000000000000000000000000000000000000000000000000000000000000001",
            "0x000000000000000000000000000000000000000000000000000000000000004a",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
-           "0x0000000000000000000000000000000000000000000000000000000000000001",
            "0x000000000000000000000000000000000000000000000000000000000000004a",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",