Merge #18859: Remove CCoinsViewCache::GetValueIn(...)

b56607a89ba112083f2b0a7b64ab18d66b26e2be 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 b56607a89ba112083f2b0a7b64ab18d66b26e2be
  promag:
    Code review ACK b56607a89ba112083f2b0a7b64ab18d66b26e2be.
  jb55:
    ACK b56607a89ba112083f2b0a7b64ab18d66b26e2be
  hebasto:
    ACK b56607a89ba112083f2b0a7b64ab18d66b26e2be, I have not tested the code, but I have reviewed it and it looks OK, I agree it can be merged.

Tree-SHA512: 2c8402b5753ec96703d12c57c3eda8eccf999ed3519134a87faaf0838cfe44b94ef384296af2a524c06c8756c0245418d181af9083548e360905fac9d79215e6

1 files changed, 0 insertions, 1 deletions

diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index 9d0ae56c3f..ddbc68f8e2 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -305,7 +305,6 @@ BOOST_AUTO_TEST_CASE(test_Get)
     t1.vout[0].scriptPubKey << OP_1;
 
     BOOST_CHECK(AreInputsStandard(CTransaction(t1), coins));
-    BOOST_CHECK_EQUAL(coins.GetValueIn(CTransaction(t1)), (50+21+22)*CENT);
 }
 
 static void CreateCreditAndSpend(const FillableSigningProvider& keystore, const CScript& outscript, CTransactionRef& output, CMutableTransaction& input, bool success = true)