ProcessSpecialTxsInBlock should respect fJustCheck

[UdjinM6]

We should NOT update internal state in any way (evodb included) when ConnectBlock is called to check block validity only.

Also invoke it after subsidy/payee checks since it could be a heavy one.

[PastaPastaPasta]

makes sense utACK

[codablock]

@UdjinM6 I'm wondering why this was needed? The idea with CEvoDb is that it's poor-mans-db-transactions based and in case we only want to check for correctness we simply roll back the db-transaction after we're done, making all changes done to CEvoDb non-persistent.

Look at

dash/src/validation.cpp

Line 3596 in 0acfbf6

auto dbTx = evoDb->BeginTransaction();

for example, it starts the DB transaction but never commits it, which results in rollback when leaving the scope of the method.

[UdjinM6]

Hmmm..... I would rather not write anything if I know I'm going to drop/rollback it the very next moment but I guess you are right and touching evodb is actually ok-ish (won't it produce some db garbage like storing non-commited txes in some cache btw? 🤔 ).

As for the rest, CDeterministicMNManager::ProcessBlock also triggers NotifyMasternodeListChanged (which deals with governance objects and votes) and CleanupCache and I'm not sure if calling these on block validity test is safe, should probably avoid it.

[codablock]

@UdjinM6 the DB transactions are in-memory, so there is no load on the disk until commitment. Rolling back simply means discarding the in-memory change-set.

But yeah, triggering NotifyMasternodeListChanged and CleanupCache should probably not happen when fJustCheck==true

[codablock]

utACK