fix: adjust GetPaymentsLimit to work correctly with historical blocks…

…, adjust sb params on regtest, tweak tests (#5641)

## Issue being fixed or feature implemented
Noticed a couple of things while I was trying to figure out if an
[issue](#5627 (comment))
@knst mentioned in #5627 could actually exist:
1. `GetPaymentsLimit()` won't work correctly with historical blocks rn.
We don't use it that way internally but it could be done via rpc and it
should provide correct results.
2. superblock params on regtest are too small to test them properly
3. because of (2) and a huge v20 activation window (comparing to sb
params) `feature_governance.py` doesn't test v20 switching states.
There's also no "sb on v20 activation block" test.

~NOTE: based on #5639 atm~

## What was done?
fix it, pls see individual commits

## How Has This Been Tested?
run tests

## Breaking Changes
n/a

## Checklist:
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [ ] I have added or updated relevant unit/integration/functional/e2e
tests
- [ ] I have made corresponding changes to the documentation
- [x] I have assigned this pull request to a milestone _(for repository
code-owners and collaborators only)_

src/chainparams.cpp

@@ -219,6 +219,7 @@ class CMainParams : public CChainParams {
         consensus.vDeployments[Consensus::DEPLOYMENT_MN_RR].bit = 10;
         consensus.vDeployments[Consensus::DEPLOYMENT_MN_RR].nStartTime = 19999999999;   // TODO: To be determined later
         consensus.vDeployments[Consensus::DEPLOYMENT_MN_RR].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+        // NOTE: nWindowSize for MN_RR __MUST__ be greater than or equal to nSuperblockMaturityWindow for CSuperblock::GetPaymentsLimit() to work correctly
         consensus.vDeployments[Consensus::DEPLOYMENT_MN_RR].nWindowSize = 4032; // TODO to be determined before v20 release: choose nWindowSize/nThresholdStart/nThresholdMin
         consensus.vDeployments[Consensus::DEPLOYMENT_MN_RR].nThresholdStart = 3226;     // 80% of 4032
         consensus.vDeployments[Consensus::DEPLOYMENT_MN_RR].nThresholdMin = 2420;       // 60% of 4032
@@ -794,8 +795,8 @@ class CRegTestParams : public CChainParams {
         consensus.nBudgetPaymentsWindowBlocks = 10;
         consensus.nSuperblockStartBlock = 1500;
         consensus.nSuperblockStartHash = uint256(); // do not check this on regtest
-        consensus.nSuperblockCycle = 10;
-        consensus.nSuperblockMaturityWindow = 2;
+        consensus.nSuperblockCycle = 20;
+        consensus.nSuperblockMaturityWindow = 10;
         consensus.nGovernanceMinQuorum = 1;
         consensus.nGovernanceFilterElements = 100;
         consensus.nMasternodeMinimumConfirmations = 1;

src/governance/classes.cpp

@@ -494,14 +494,16 @@ CAmount CSuperblock::GetPaymentsLimit(int nBlockHeight)
         return 0;
     }
 
-    const CBlockIndex* tipIndex = ::ChainActive().Tip();
-    const auto v20_state = llmq::utils::GetV20State(tipIndex);
+    const CBlockIndex* pindex = ::ChainActive().Tip();
+    if (pindex->nHeight > nBlockHeight) pindex = pindex->GetAncestor(nBlockHeight);
+
+    const auto v20_state = llmq::utils::GetV20State(pindex);
     bool fV20Active{v20_state == ThresholdState::ACTIVE};
-    if (!fV20Active && nBlockHeight > tipIndex->nHeight) {
+    if (!fV20Active && nBlockHeight > pindex->nHeight) {
         // If fV20Active isn't active yet and nBlockHeight refers to a future SuperBlock
         // then we need to check if the fork is locked_in and see if it will be active by the time of the future SuperBlock
         if (v20_state == ThresholdState::LOCKED_IN) {
-            int activation_height = llmq::utils::GetV20Since(tipIndex) + static_cast<int>(Params().GetConsensus().vDeployments[Consensus::DEPLOYMENT_V20].nWindowSize);
+            int activation_height = llmq::utils::GetV20Since(pindex) + static_cast<int>(Params().GetConsensus().vDeployments[Consensus::DEPLOYMENT_V20].nWindowSize);
             if (nBlockHeight >= activation_height) {
                 fV20Active = true;
             }

src/test/block_reward_reallocation_tests.cpp

@@ -214,7 +214,7 @@ BOOST_FIXTURE_TEST_CASE(block_reward_reallocation, TestChainBRRBeforeActivationS
         BOOST_CHECK_EQUAL(pblocktemplate->voutMasternodePayments[0].nValue, masternode_payment);
     }
 
-    for ([[maybe_unused]] auto _ : irange::range(9)) {
+    for ([[maybe_unused]] auto _ : irange::range(consensus_params.nSuperblockCycle - 1)) {
         CreateAndProcessBlock({}, coinbaseKey);
     }
 
@@ -234,7 +234,7 @@ BOOST_FIXTURE_TEST_CASE(block_reward_reallocation, TestChainBRRBeforeActivationS
     // there will be 19 adjustments, 3 superblocks long each
     for ([[maybe_unused]] auto i : irange::range(19)) {
         for ([[maybe_unused]] auto j : irange::range(3)) {
-            for ([[maybe_unused]] auto k : irange::range(10)) {
+            for ([[maybe_unused]] auto k : irange::range(consensus_params.nSuperblockCycle)) {
                 CreateAndProcessBlock({}, coinbaseKey);
             }
             LOCK(cs_main);
@@ -256,15 +256,15 @@ BOOST_FIXTURE_TEST_CASE(block_reward_reallocation, TestChainBRRBeforeActivationS
         const CAmount block_subsidy = GetBlockSubsidyInner(tip->nBits, tip->nHeight, consensus_params, isV20Active);
         const CAmount block_subsidy_sb = GetSuperblockSubsidyInner(tip->nBits, tip->nHeight, consensus_params, isV20Active);
         CAmount block_subsidy_potential = block_subsidy + block_subsidy_sb;
-        BOOST_CHECK_EQUAL(block_subsidy_potential, 113573330);
+        BOOST_CHECK_EQUAL(block_subsidy_potential, 84437941);
         CAmount expected_block_reward = block_subsidy_potential - block_subsidy_potential / 5;
 
         const CAmount masternode_payment = GetMasternodePayment(tip->nHeight, block_subsidy, isV20Active);
         const auto pblocktemplate = BlockAssembler(*sporkManager, *governance, *m_node.llmq_ctx, *m_node.evodb, m_node.chainman->ActiveChainstate(), *m_node.mempool, Params()).CreateNewBlock(coinbasePubKey);
         BOOST_CHECK_EQUAL(pblocktemplate->block.vtx[0]->GetValueOut(), expected_block_reward);
-        BOOST_CHECK_EQUAL(pblocktemplate->block.vtx[0]->GetValueOut(), 90858664);
+        BOOST_CHECK_EQUAL(pblocktemplate->block.vtx[0]->GetValueOut(), 67550353);
         BOOST_CHECK_EQUAL(pblocktemplate->voutMasternodePayments[0].nValue, masternode_payment);
-        BOOST_CHECK_EQUAL(pblocktemplate->voutMasternodePayments[0].nValue, 68143998); // 0.75
+        BOOST_CHECK_EQUAL(pblocktemplate->voutMasternodePayments[0].nValue, 50662764); // 0.75
     }
     BOOST_CHECK(!llmq::utils::IsMNRewardReallocationActive(m_node.chainman->ActiveChain().Tip()));
 
@@ -274,7 +274,7 @@ BOOST_FIXTURE_TEST_CASE(block_reward_reallocation, TestChainBRRBeforeActivationS
     // Reward split should stay ~75/25 after reallocation is done,
     // check 10 next superblocks
     for ([[maybe_unused]] auto i : irange::range(10)) {
-        for ([[maybe_unused]] auto k : irange::range(10)) {
+        for ([[maybe_unused]] auto k : irange::range(consensus_params.nSuperblockCycle)) {
             CreateAndProcessBlock({}, coinbaseKey);
         }
         LOCK(cs_main);
@@ -307,9 +307,9 @@ BOOST_FIXTURE_TEST_CASE(block_reward_reallocation, TestChainBRRBeforeActivationS
         masternode_payment -= platform_payment;
         const auto pblocktemplate = BlockAssembler(*sporkManager, *governance, *m_node.llmq_ctx, *m_node.evodb, m_node.chainman->ActiveChainstate(), *m_node.mempool, Params()).CreateNewBlock(coinbasePubKey);
 
-        // At this height (3178) the block subsidy is 105460950.
         CAmount block_subsidy_potential = block_subsidy + block_subsidy_sb;
-        BOOST_CHECK_EQUAL(block_subsidy_potential, 105460950);
+        BOOST_CHECK_EQUAL(tip->nHeight, 3858);
+        BOOST_CHECK_EQUAL(block_subsidy_potential, 78406660);
         // Treasury is 20% since MNRewardReallocation
         CAmount expected_block_reward = block_subsidy_potential - block_subsidy_potential / 5;
         // Since MNRewardReallocation, MN reward share is 75% of the block reward