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fuzz: exercise `EmplaceCoinInternalDANGER` calls 

The exception could be triggered during fuzz testing which leaves the accounting in a bad state.
Instead of documenting that, the accounting was fixed in a previous commit and the fuzz test simplified.
Also added `EmplaceCoinInternalDANGER` alternative to fuzzing to exercise that area of te code as well.
This commit is contained in:
Lőrinc 2025-10-07 21:27:14 -05:00
parent 9a1003b2e3
commit a9eb8dfab1
1 changed files with 10 additions and 16 deletions
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26
src/test/fuzz/coins_view.cpp
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@ -59,25 +59,19 @@ void TestCoinsView(FuzzedDataProvider& fuzzed_data_provider, CCoinsView& backend
if (random_coin.IsSpent()) {
return;
}
Coin coin = random_coin;
bool expected_code_path = false;
const bool possible_overwrite = fuzzed_data_provider.ConsumeBool();
try {
coins_view_cache.AddCoin(random_out_point, std::move(coin), possible_overwrite);
expected_code_path = true;
} catch (const std::logic_error& e) {
if (e.what() == std::string{"Attempted to overwrite an unspent coin (when possible_overwrite is false)"}) {
COutPoint outpoint{random_out_point};
Coin coin{random_coin};
if (fuzzed_data_provider.ConsumeBool()) {
const bool possible_overwrite{fuzzed_data_provider.ConsumeBool()};
try {
coins_view_cache.AddCoin(outpoint, std::move(coin), possible_overwrite);
} catch (const std::logic_error& e) {
assert(e.what() == std::string{"Attempted to overwrite an unspent coin (when possible_overwrite is false)"});
assert(!possible_overwrite);
expected_code_path = true;
// AddCoin() decreases cachedCoinsUsage by the memory usage of the old coin at the beginning and
// increases it by the value of the new coin at the end. If it throws in the process, the value
// of cachedCoinsUsage would have been incorrectly decreased, leading to an underflow later on.
// To avoid this, use Flush() to reset the value of cachedCoinsUsage in sync with the cacheCoins
// mapping.
(void)coins_view_cache.Flush();
}
} else {
coins_view_cache.EmplaceCoinInternalDANGER(std::move(outpoint), std::move(coin));
}
assert(expected_code_path);
},
[&] {
(void)coins_view_cache.Flush();