Coming to agreement with geth on RIPEMD touch revert - another alternative solution

[gumb0]

(Alternative solutions were considered in #5652 and #5663)

This is the old issue, originated that time when both Geth and Parity had incorrect revert behavior, and then it was decided to introduce a hack into consensus rules instead of doing huge chain reorg.

The buggy behavior that is now a rule is basically: when precompiled contract with address 0x03 (RIPEMD160) is touched, then exception happens and state changes are reverted, this address should be still considered touched in the end, so that "remove empty touched accounts" rule (EIP-158) deletes it from the state at the end of transaction.

There are several related tests created after this incident:

• GeneralStateTests/stSpecialTest/tx_xcf416c53 - emulates the transaction where this special behavior took place on the main net. Here the gas given to CALL to RIPEMD is not enough, so the CALL itself fails, but then transaction proceeds further till success. RIPEMD stays touched and then is deleted. All clients pass this test (otherwise they wouldn't be able to do full sync)
• GeneralStateTests/stRevertTest/RevertPrecompiledTouch and GeneralStateTests/stRevertTest/RevertPrecompiledTouch_storage - here CALL to RIPEMD succeeds, but later execution runs out of gas. Changes to the state are reverted, but RIPEMD stays touched and then is deleted. In these tests we have different results than geth.

Dimitriy now has regenerated these latter tests via geth, and now aleth doesn't pass them.

In geth all of these cases look to be handled by just one hack https://github.com/ethereum/go-ethereum/blob/7527215a68eaac8a880be83f3f1ded0ed82f6650/core/state/state_object.go#L145-L149

Our current hack covers only the first tx_xcf416c53 case, because for us failing CALL to precompile is a special case, that doesn't invoke any rollback

aleth/libethereum/Executive.cpp

Lines 313 to 318 in 007d89a

	// Empty precompiled contracts need to be deleted even in case of OOG
	// because the bug in both Geth and Parity led to deleting RIPEMD precompiled in this case
	// see https://github.com/ethereum/go-ethereum/pull/3341/files#diff-2433aa143ee4772026454b8abd76b9dd
	// We mark the account as touched here, so that is can be removed among other touched empty accounts (after tx finalization)
	if (m_envInfo.number() >= m_sealEngine.chainParams().EIP158ForkBlock)
	m_s.addBalance(_p.codeAddress, 0);

This PR change this hack to behavior similar to geth, covering both not enough gas passed to CALL and OOG after CALL.

More references:

• Original geth's fix https://github.com/ethereum/go-ethereum/pull/3341/files#diff-2433aa143ee4772026454b8abd76b9dd
• More detailed description Clarification about when touchedness is reverted during state clearance EIPs#716
• Recent mention in AllCoreDevs chat https://gitter.im/ethereum/AllCoreDevs?at=5ce3bd9863dea422b4bc9b91
• Yellow Paper mentions this anomaly in Appendix K https://ethereum.github.io/yellowpaper/paper.pdf

[codecov-io]

Codecov Report

Merging #5664 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #5664      +/-   ##
==========================================
+ Coverage      63%   63.01%   +<.01%     
==========================================
  Files         350      350              
  Lines       29908    29912       +4     
  Branches     3350     3352       +2     
==========================================
+ Hits        18845    18849       +4     
+ Misses       9848     9846       -2     
- Partials     1215     1217       +2

[gumb0]

Updated tests and added changelog item.