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Adding comments to test local_votes_cache_fork and documenting a race (#3937)

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There is a race condition, if the vote arrives before the block then
the vote is wasted and the test fails. We could resend the vote but then
there is a race condition between the vote resending and the election
reaching quorum on node1. The proper fix would be to observe on node2
that both the block and the vote arrived in whatever order.
The real node will do a confirm request if it needs to find a lost vote.
This commit is contained in:
Dimitrios Siganos 2022-09-14 08:29:24 +01:00 • committed by GitHub
commit a4d67891f4
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1 changed files with 30 additions and 9 deletions
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39
nano/core_test/node.cpp
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@ -2492,11 +2492,13 @@ TEST (node, local_votes_cache_fork)
TEST (node, vote_republish)
{
nano::test::system system (2);
auto & node1 (*system.nodes[0]);
auto & node2 (*system.nodes[1]);
auto & node1 = *system.nodes[0];
auto & node2 = *system.nodes[1];
nano::keypair key2;
// by not setting a private key on node1's wallet, it is stopped from voting
// by not setting a private key on node1's wallet for genesis account, it is stopped from voting
system.wallet (1)->insert_adhoc (key2.prv);
// send1 and send2 are forks of each other
nano::send_block_builder builder;
auto send1 = builder.make_block ()
.previous (nano::dev::genesis->hash ())
@ -2512,19 +2514,38 @@ TEST (node, vote_republish)
.sign (nano::dev::genesis_key.prv, nano::dev::genesis_key.pub)
.work (*system.work.generate (nano::dev::genesis->hash ()))
.build_shared ();
// process send1 first, this will make sure send1 goes into the ledger and an election is started
node1.process_active (send1);
ASSERT_TIMELY (5s, node2.block (send1->hash ()));
ASSERT_TIMELY (5s, node1.active.active (*send1));
ASSERT_TIMELY (5s, node2.active.active (*send1));
// now process send2, send2 will not go in the ledger because only the first block of a fork goes in the ledger
node1.process_active (send2);
ASSERT_TIMELY (5s, node1.active.active (*send2));
// send2 cannot be synced because it is not in the ledger of node1, it is only in the election object in RAM on node1
ASSERT_FALSE (node1.block (send2->hash ()));
// the vote causes the election to reach quorum and for the vote (and block?) to be published from node1 to node2
auto vote (std::make_shared<nano::vote> (nano::dev::genesis_key.pub, nano::dev::genesis_key.prv, nano::vote::timestamp_max, nano::vote::duration_max, std::vector<nano::block_hash>{ send2->hash () }));
ASSERT_TRUE (node1.active.active (*send1));
ASSERT_TIMELY (10s, node2.active.active (*send1));
node1.vote_processor.vote (vote, std::make_shared<nano::transport::fake::channel> (node1));
ASSERT_TIMELY (10s, node1.block (send2->hash ()));
ASSERT_TIMELY (10s, node2.block (send2->hash ()));
// FIXME: there is a race condition here, if the vote arrives before the block then the vote is wasted and the test fails
// we could resend the vote but then there is a race condition between the vote resending and the election reaching quorum on node1
// the proper fix would be to observe on node2 that both the block and the vote arrived in whatever order
// the real node will do a confirm request if it needs to find a lost vote
// check that send2 won on both nodes
ASSERT_TIMELY (5s, node1.block_confirmed (send2->hash ()));
ASSERT_TIMELY (5s, node2.block_confirmed (send2->hash ()));
// check that send1 is deleted from the ledger on nodes
ASSERT_FALSE (node1.block (send1->hash ()));
ASSERT_FALSE (node2.block (send1->hash ()));
ASSERT_TIMELY (10s, node2.balance (key2.pub) == node1.config.receive_minimum.number () * 2);
ASSERT_TIMELY (10s, node1.balance (key2.pub) == node1.config.receive_minimum.number () * 2);
ASSERT_TIMELY (5s, node2.balance (key2.pub) == node1.config.receive_minimum.number () * 2);
ASSERT_TIMELY (5s, node1.balance (key2.pub) == node1.config.receive_minimum.number () * 2);
}
TEST (node, vote_by_hash_bundle)