Merge pull request #1657 from poanetwork/gs-fix-consensus-loss

Force consensus loss for parent block if its hash mismatches parent_hash

CHANGELOG.md

@@ -16,6 +16,7 @@
  - [#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
 

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 ->
-          from(transaction in acc, or_where: transaction.block_hash == ^hash and transaction.block_number == ^number)
+      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
+
+  defp where_invalid_parent(blocks_changes) when is_list(blocks_changes) do
+    initial = from(b in Block, where: false)
 
-        true ->
-          from(transaction in acc, or_where: transaction.block_hash != ^hash and transaction.block_number == ^number)
+    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/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