fix proofHash related sporadic concurrency bug

[stenolog]

• fixes proofsForTransactions in UtxoStateReader can modify the underlying tree #1387
• fixes Fix unstable "concurrent applyModifier() and proofsForTransactions()" test #1023

Testing

This needs a long-running stress-test outside of the CI.

See branch:

https://github.com/stenolog/ergo/tree/i1387-i1023-repro-and-fix

for the fix incl. the reproducer and documentation.

Quick Examples

# with fix
cd ~
mkdir proofhash
cd proofhash
git clone -b i1387-i1023-repro-and-fix https://github.com/stenolog/ergo.git
cd ergo
sbt compile && time while [ $? -eq 0 ]; do sbt "testOnly *UtxoStateSpecification -- -z looper"; done

in another window

# without fix, should fail in around 10 min.
cd ~/proofhash
git clone -b i1387-i1023-repro-and-fix https://github.com/stenolog/ergo.git ergofail
cd ergofail
git checkout HEAD~1 # disable fix (last commit)
sbt compile && time while [ $? -eq 0 ]; do sbt "testOnly *UtxoStateSpecification -- -z looper"; done

[kushti]

awesome work!

Please send me your reward address to [email protected] or PM over Discord to get attached bounty paid!

[stenolog]

awesome work!

Thank you. Email send!