b56607a89b Remove CCoinsViewCache::GetValueIn(...) (practicalswift)
Pull request description:
Remove `CCoinsViewCache::GetValueIn(...)`.
Fixes#18858.
It seems like `GetValueIn` was added in #748 ("Pay-to-script-hash (OP_EVAL replacement)", merged in 2012) and the last use in validation code was removed in #8498 ("Near-Bugfix: Optimization: Minimize the number of times it is checked that no money...", merged in 2017).
`CCoinsViewCache::GetValueIn(…)` performs money summation like this:
```c++
CAmount CCoinsViewCache::GetValueIn(const CTransaction& tx) const
{
if (tx.IsCoinBase())
return 0;
CAmount nResult = 0;
for (unsigned int i = 0; i < tx.vin.size(); i++)
nResult += AccessCoin(tx.vin[i].prevout).out.nValue;
return nResult;
}
```
Note that no check is done to make sure that the resulting `nResult` is such that it stays within the money bounds (`MoneyRange(nResult)`), or that the summation does not trigger a signed integer overflow.
Proof of concept output:
```
coins.cpp:243:17: runtime error: signed integer overflow: 9223200000000000000 + 2100000000000000 cannot be represented in type 'long'
GetValueIn = -9221444073709551616
```
Proof of concept code:
```c++
CMutableTransaction mutable_transaction;
mutable_transaction.vin.resize(4393);
Coin coin;
coin.out.nValue = MAX_MONEY;
assert(MoneyRange(coin.out.nValue));
CCoinsCacheEntry coins_cache_entry;
coins_cache_entry.coin = coin;
coins_cache_entry.flags = CCoinsCacheEntry::DIRTY;
CCoinsView backend_coins_view;
CCoinsViewCache coins_view_cache{&backend_coins_view};
CCoinsMap coins_map;
coins_map.emplace(COutPoint{}, std::move(coins_cache_entry));
coins_view_cache.BatchWrite(coins_map, {});
const CAmount total_value_in = coins_view_cache.GetValueIn(CTransaction{mutable_transaction});
std::cout << "GetValueIn = " << total_value_in << std::endl;
```
ACKs for top commit:
MarcoFalke:
ACK b56607a89b
promag:
Code review ACK b56607a89b.
jb55:
ACK b56607a89b
hebasto:
ACK b56607a89b, I have not tested the code, but I have reviewed it and it looks OK, I agree it can be merged.
Tree-SHA512: 2c8402b5753ec96703d12c57c3eda8eccf999ed3519134a87faaf0838cfe44b94ef384296af2a524c06c8756c0245418d181af9083548e360905fac9d79215e6
74a1152f25