From 52a0b19d5e34745b818021c6345a3277999effb6 Mon Sep 17 00:00:00 2001
From: pasqu4le <pasqu4le@gmail.com>
Date: Wed, 7 Aug 2019 18:35:59 +0200
Subject: [PATCH] Avoid importing internal_transactions of pending transactions

Problem: While fetching the internal transactions for a block sometimes we receive some that are part of a pending transaction.
By inserting them we also try to update the pending transaction's field, but this violates the `status` check constraint (rightfully).

Solution: Filter out internal_transactions that are part of a pending transaction.
---
 CHANGELOG.md                                  |  1 +
 .../import/runner/internal_transactions.ex    | 28 ++++++++++++++++---
 .../runner/internal_transactions_test.exs     | 24 +++++++++++++++-
 3 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1ed41ca1f7..9c6abd2066 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 - [#2456](https://github.com/poanetwork/blockscout/pull/2456) - fetch pending transactions for geth
 
 ### Fixes
+- [#2523](https://github.com/poanetwork/blockscout/pull/2523) - Avoid importing internal_transactions of pending transactions
 - [#2503](https://github.com/poanetwork/blockscout/pull/2503) - Mitigate autocompletion library influence to page loading performance
 - [#2502](https://github.com/poanetwork/blockscout/pull/2502) - increase reward task timeout
 - [#2463](https://github.com/poanetwork/blockscout/pull/2463) - dark theme fixes
diff --git a/apps/explorer/lib/explorer/chain/import/runner/internal_transactions.ex b/apps/explorer/lib/explorer/chain/import/runner/internal_transactions.ex
index 5e2e4e32f5..50529e8ce8 100644
--- a/apps/explorer/lib/explorer/chain/import/runner/internal_transactions.ex
+++ b/apps/explorer/lib/explorer/chain/import/runner/internal_transactions.ex
@@ -73,10 +73,12 @@ defmodule Explorer.Chain.Import.Runner.InternalTransactions do
     # order so that row ShareLocks are grabbed in a consistent order
     ordered_changes_list = Enum.sort_by(changes_list, &{&1.transaction_hash, &1.index})
 
+    final_changes_list = reject_pending_transactions(ordered_changes_list, repo)
+
     {:ok, internal_transactions} =
       Import.insert_changes_list(
         repo,
-        ordered_changes_list,
+        final_changes_list,
         conflict_target: [:transaction_hash, :index],
         for: InternalTransaction,
         on_conflict: on_conflict,
@@ -156,6 +158,7 @@ defmodule Explorer.Chain.Import.Runner.InternalTransactions do
       from(
         t in Transaction,
         where: t.hash in ^ordered_transaction_hashes,
+        where: not is_nil(t.block_hash),
         update: [
           set: [
             internal_transactions_indexed_at: ^timestamps.updated_at,
@@ -180,10 +183,8 @@ defmodule Explorer.Chain.Import.Runner.InternalTransactions do
         ]
       )
 
-    transaction_count = Enum.count(ordered_transaction_hashes)
-
     try do
-      {^transaction_count, result} = repo.update_all(query, [], timeout: timeout)
+      {_transaction_count, result} = repo.update_all(query, [], timeout: timeout)
 
       {:ok, result}
     rescue
@@ -191,4 +192,23 @@ defmodule Explorer.Chain.Import.Runner.InternalTransactions do
         {:error, %{exception: postgrex_error, transaction_hashes: ordered_transaction_hashes}}
     end
   end
+
+  defp reject_pending_transactions(ordered_changes_list, repo) do
+    transaction_hashes =
+      ordered_changes_list
+      |> Enum.map(& &1.transaction_hash)
+      |> Enum.dedup()
+
+    query =
+      from(t in Transaction,
+        where: t.hash in ^transaction_hashes,
+        where: is_nil(t.block_hash),
+        select: t.hash
+      )
+
+    pending_transactions = repo.all(query)
+
+    ordered_changes_list
+    |> Enum.reject(fn %{transaction_hash: hash} -> Enum.member?(pending_transactions, hash) end)
+  end
 end
diff --git a/apps/explorer/test/explorer/chain/import/runner/internal_transactions_test.exs b/apps/explorer/test/explorer/chain/import/runner/internal_transactions_test.exs
index f5c080991e..66d62ae940 100644
--- a/apps/explorer/test/explorer/chain/import/runner/internal_transactions_test.exs
+++ b/apps/explorer/test/explorer/chain/import/runner/internal_transactions_test.exs
@@ -2,7 +2,7 @@ defmodule Explorer.Chain.Import.Runner.InternalTransactionsTest do
   use Explorer.DataCase
 
   alias Ecto.Multi
-  alias Explorer.Chain.{Data, Wei, Transaction}
+  alias Explorer.Chain.{Data, Wei, Transaction, InternalTransaction}
   alias Explorer.Chain.Import.Runner.InternalTransactions
 
   describe "run/1" do
@@ -20,6 +20,28 @@ defmodule Explorer.Chain.Import.Runner.InternalTransactionsTest do
 
       assert :error == Repo.get(Transaction, transaction.hash).status
     end
+
+    test "pending transactions don't get updated not its internal_transactions inserted" do
+      transaction = insert(:transaction) |> with_block(status: :ok)
+      pending = insert(:transaction)
+
+      assert :ok == transaction.status
+      assert is_nil(pending.block_hash)
+
+      index = 0
+
+      transaction_changes = make_internal_transaction_changes(transaction.hash, index, nil)
+      pending_changes = make_internal_transaction_changes(pending.hash, index, nil)
+
+      assert {:ok, _} = run_internal_transactions([transaction_changes, pending_changes])
+
+      assert %InternalTransaction{} =
+               Repo.one(from(i in InternalTransaction, where: i.transaction_hash == ^transaction.hash))
+
+      assert from(i in InternalTransaction, where: i.transaction_hash == ^pending.hash) |> Repo.one() |> is_nil()
+
+      assert is_nil(Repo.get(Transaction, pending.hash).block_hash)
+    end
   end
 
   defp run_internal_transactions(changes_list) when is_list(changes_list) do