bitcoin/src/test/validationinterface_tests.cpp

// Copyright (c) 2020 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <boost/test/unit_test.hpp>

#include <consensus/validation.h>
#include <primitives/block.h>
#include <scheduler.h>
#include <util/check.h>
#include <validationinterface.h>

BOOST_AUTO_TEST_SUITE(validationinterface_tests)

class TestInterface : public CValidationInterface
{
public:
    TestInterface(std::function<void()> on_call = nullptr, std::function<void()> on_destroy = nullptr)
        : m_on_call(std::move(on_call)), m_on_destroy(std::move(on_destroy))
    {
    }
    virtual ~TestInterface()
    {
        if (m_on_destroy) m_on_destroy();
    }
    void BlockChecked(const CBlock& block, const BlockValidationState& state) override
    {
        if (m_on_call) m_on_call();
    }
    static void Call()
    {
        CBlock block;
        BlockValidationState state;
        GetMainSignals().BlockChecked(block, state);
    }
    std::function<void()> m_on_call;
    std::function<void()> m_on_destroy;
};

// Regression test to ensure UnregisterAllValidationInterfaces calls don't
// destroy a validation interface while it is being called. Bug:
// https://github.com/bitcoin/bitcoin/pull/18551
BOOST_AUTO_TEST_CASE(unregister_all_during_call)
{
    bool destroyed = false;

    CScheduler scheduler;
    GetMainSignals().RegisterBackgroundSignalScheduler(scheduler);
    RegisterSharedValidationInterface(std::make_shared<TestInterface>(
        [&] {
            // First call should decrements reference count 2 -> 1
            UnregisterAllValidationInterfaces();
            BOOST_CHECK(!destroyed);
            // Second call should not decrement reference count 1 -> 0
            UnregisterAllValidationInterfaces();
            BOOST_CHECK(!destroyed);
        },
        [&] { destroyed = true; }));
    TestInterface::Call();
    BOOST_CHECK(destroyed);
}

BOOST_AUTO_TEST_SUITE_END()