refactor: trim and document assumptions for Get*MN* and friends

src/evo/deterministicmns.cpp

@@ -428,7 +428,7 @@ CDeterministicMNList CDeterministicMNList::ApplyDiff(gsl::not_null<const CBlockI
     for (const auto& id : diff.removedMns) {
         auto dmn = result.GetMNByInternalId(id);
         if (!dmn) {
-            throw(std::runtime_error(strprintf("%s: can't find a removed masternode, id=%d", __func__, id)));
+            throw std::runtime_error(strprintf("%s: can't find a removed masternode, id=%d", __func__, id));
         }
         result.RemoveMN(dmn->proTxHash);
     }
@@ -437,6 +437,9 @@ CDeterministicMNList CDeterministicMNList::ApplyDiff(gsl::not_null<const CBlockI
     }
     for (const auto& p : diff.updatedMNs) {
         auto dmn = result.GetMNByInternalId(p.first);
+        if (!dmn) {
+            throw std::runtime_error(strprintf("%s: can't find an updated masternode, id=%d", __func__, p.first));
+        }
         result.UpdateMN(*dmn, p.second);
     }
 
@@ -818,7 +821,7 @@ bool CDeterministicMNManager::BuildNewListFromBlock(const CBlock& block, gsl::no
                 return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-protx-dup-addr");
             }
 
-            CDeterministicMNCPtr dmn = newList.GetMN(opt_proTx->proTxHash);
+            auto dmn = newList.GetMN(opt_proTx->proTxHash);
             if (!dmn) {
                 return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-protx-hash");
             }
@@ -859,7 +862,7 @@ bool CDeterministicMNManager::BuildNewListFromBlock(const CBlock& block, gsl::no
                 return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-protx-payload");
             }
 
-            CDeterministicMNCPtr dmn = newList.GetMN(opt_proTx->proTxHash);
+            auto dmn = newList.GetMN(opt_proTx->proTxHash);
             if (!dmn) {
                 return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-protx-hash");
             }
@@ -887,7 +890,7 @@ bool CDeterministicMNManager::BuildNewListFromBlock(const CBlock& block, gsl::no
                 return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-protx-payload");
             }
 
-            CDeterministicMNCPtr dmn = newList.GetMN(opt_proTx->proTxHash);
+            auto dmn = newList.GetMN(opt_proTx->proTxHash);
             if (!dmn) {
                 return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-protx-hash");
             }
@@ -947,6 +950,8 @@ bool CDeterministicMNManager::BuildNewListFromBlock(const CBlock& block, gsl::no
     // current block. We still pay that MN one last time, however.
     if (payee && newList.HasMN(payee->proTxHash)) {
         auto dmn = newList.GetMN(payee->proTxHash);
+        // HasMN has reported that GetMN should succeed, enforce that.
+        assert(dmn);
         auto newState = std::make_shared<CDeterministicMNState>(*dmn->pdmnState);
         newState->nLastPaidHeight = nHeight;
         // Starting from v19 and until MNRewardReallocation, EvoNodes will be paid 4 blocks in a row
@@ -962,6 +967,9 @@ bool CDeterministicMNManager::BuildNewListFromBlock(const CBlock& block, gsl::no
         newList.UpdateMN(payee->proTxHash, newState);
         if (debugLogs) {
             dmn = newList.GetMN(payee->proTxHash);
+            // Since the previous GetMN query returned a value, after an update, querying the same
+            // hash *must* give us a result. If it doesn't, that would be a potential logic bug.
+            assert(dmn);
             LogPrint(BCLog::MNPAYMENTS, "CDeterministicMNManager::%s -- MN %s, nConsecutivePayments=%d\n",
                       __func__, dmn->proTxHash.ToString(), dmn->pdmnState->nConsecutivePayments);
         }

src/governance/governance.cpp

@@ -1601,6 +1601,9 @@ void CGovernanceManager::RemoveInvalidVotes()
     std::vector<COutPoint> changedKeyMNs;
     for (const auto& p : diff.updatedMNs) {
         auto oldDmn = lastMNListForVotingKeys->GetMNByInternalId(p.first);
+        // BuildDiff will construct itself with MNs that we already have knowledge
+        // of, meaning that fetch operations should never fail.
+        assert(oldDmn);
         if ((p.second.fields & CDeterministicMNStateDiff::Field_keyIDVoting) && p.second.state.keyIDVoting != oldDmn->pdmnState->keyIDVoting) {
             changedKeyMNs.emplace_back(oldDmn->collateralOutpoint);
         } else if ((p.second.fields & CDeterministicMNStateDiff::Field_pubKeyOperator) && p.second.state.pubKeyOperator != oldDmn->pdmnState->pubKeyOperator) {
@@ -1609,6 +1612,9 @@ void CGovernanceManager::RemoveInvalidVotes()
     }
     for (const auto& id : diff.removedMns) {
         auto oldDmn = lastMNListForVotingKeys->GetMNByInternalId(id);
+        // BuildDiff will construct itself with MNs that we already have knowledge
+        // of, meaning that fetch operations should never fail.
+        assert(oldDmn);
         changedKeyMNs.emplace_back(oldDmn->collateralOutpoint);
     }
 

src/masternode/node.cpp

@@ -129,7 +129,7 @@ void CActiveMasternodeManager::InitInternal(const CBlockIndex* pindex)
 
     CDeterministicMNList mnList = Assert(m_dmnman)->GetListForBlock(pindex);
 
-    CDeterministicMNCPtr dmn = mnList.GetMNByOperatorKey(m_info.blsPubKeyOperator);
+    auto dmn = mnList.GetMNByOperatorKey(m_info.blsPubKeyOperator);
     if (!dmn) {
         // MN not appeared on the chain yet
         return;
@@ -202,6 +202,9 @@ void CActiveMasternodeManager::UpdatedBlockTip(const CBlockIndex* pindexNew, con
 
         auto oldDmn = oldMNList.GetMN(cur_protx_hash);
         auto newDmn = newMNList.GetMN(cur_protx_hash);
+        if (!oldDmn || !newDmn) {
+            return reset(MasternodeState::SOME_ERROR);
+        }
         if (newDmn->pdmnState->pubKeyOperator != oldDmn->pdmnState->pubKeyOperator) {
             // MN operator key changed or revoked
             return reset(MasternodeState::OPERATOR_KEY_CHANGED);

src/qt/masternodelist.cpp

@@ -354,7 +354,8 @@ CDeterministicMNCPtr MasternodeList::GetSelectedDIP3MN()
     uint256 proTxHash;
     proTxHash.SetHex(strProTxHash);
 
-    return clientModel->getMasternodeList().first.GetMN(proTxHash);;
+    // Caller is responsible for nullptr checking return value
+    return clientModel->getMasternodeList().first.GetMN(proTxHash);
 }
 
 void MasternodeList::extraInfoDIP3_clicked()

src/rpc/evo.cpp

@@ -1635,13 +1635,19 @@ static RPCHelpMan protx_listdiff()
     UniValue jremovedMNs(UniValue::VARR);
     for(const auto& internal_id : mnDiff.removedMns) {
         auto dmn = baseBlockMNList.GetMNByInternalId(internal_id);
+        // BuildDiff will construct itself with MNs that we already have knowledge
+        // of, meaning that fetch operations should never fail.
+        CHECK_NONFATAL(dmn);
         jremovedMNs.push_back(dmn->proTxHash.ToString());
     }
     ret.pushKV("removedMNs", jremovedMNs);
 
     UniValue jupdatedMNs(UniValue::VARR);
     for(const auto& [internal_id, stateDiff] : mnDiff.updatedMNs) {
         auto dmn = baseBlockMNList.GetMNByInternalId(internal_id);
+        // BuildDiff will construct itself with MNs that we already have knowledge
+        // of, meaning that fetch operations should never fail.
+        CHECK_NONFATAL(dmn);
         UniValue obj(UniValue::VOBJ);
         obj.pushKV(dmn->proTxHash.ToString(), stateDiff.ToJson(dmn->nType));
         jupdatedMNs.push_back(obj);

src/rpc/masternode.cpp

@@ -229,7 +229,7 @@ static RPCHelpMan masternode_status()
     // keep compatibility with legacy status for now (might get deprecated/removed later)
     mnObj.pushKV("outpoint", node.mn_activeman->GetOutPoint().ToStringShort());
     mnObj.pushKV("service", node.mn_activeman->GetService().ToStringAddrPort());
-    CDeterministicMNCPtr dmn = CHECK_NONFATAL(node.dmnman)->GetListAtChainTip().GetMN(node.mn_activeman->GetProTxHash());
+    auto dmn = CHECK_NONFATAL(node.dmnman)->GetListAtChainTip().GetMN(node.mn_activeman->GetProTxHash());
     if (dmn) {
         mnObj.pushKV("proTxHash", dmn->proTxHash.ToString());
         mnObj.pushKV("type", std::string(GetMnType(dmn->nType).description));
@@ -322,9 +322,11 @@ static RPCHelpMan masternode_winners()
     for (int h = nStartHeight; h <= nChainTipHeight; h++) {
         const CBlockIndex* pIndex = pindexTip->GetAncestor(h - 1);
         auto payee = node.dmnman->GetListForBlock(pIndex).GetMNPayee(pIndex);
-        std::string strPayments = GetRequiredPaymentsString(*CHECK_NONFATAL(node.govman), tip_mn_list, h, payee);
-        if (strFilter != "" && strPayments.find(strFilter) == std::string::npos) continue;
-        obj.pushKV(strprintf("%d", h), strPayments);
+        if (payee) {
+            std::string strPayments = GetRequiredPaymentsString(*CHECK_NONFATAL(node.govman), tip_mn_list, h, payee);
+            if (strFilter != "" && strPayments.find(strFilter) == std::string::npos) continue;
+            obj.pushKV(strprintf("%d", h), strPayments);
+        }
     }
 
     auto projection = node.dmnman->GetListForBlock(pindexTip).GetProjectedMNPayees(pindexTip, 20);

src/test/evo_deterministicmns_tests.cpp

@@ -467,6 +467,7 @@ void FuncDIP3Protx(TestChainSetup& setup)
     // check MN reward payments
     for (size_t i = 0; i < 20; i++) {
         auto dmnExpectedPayee = dmnman.GetListAtChainTip().GetMNPayee(chainman.ActiveChain().Tip());
+        BOOST_ASSERT(dmnExpectedPayee);
 
         CBlock block = setup.CreateAndProcessBlock({}, setup.coinbaseKey);
         dmnman.UpdatedBlockTip(chainman.ActiveChain().Tip());
@@ -525,7 +526,7 @@ void FuncDIP3Protx(TestChainSetup& setup)
     // test that the revoked MN does not get paid anymore
     for (size_t i = 0; i < 20; i++) {
         auto dmnExpectedPayee = dmnman.GetListAtChainTip().GetMNPayee(chainman.ActiveChain().Tip());
-        BOOST_REQUIRE(dmnExpectedPayee->proTxHash != dmnHashes[0]);
+        BOOST_REQUIRE(dmnExpectedPayee && dmnExpectedPayee->proTxHash != dmnHashes[0]);
 
         CBlock block = setup.CreateAndProcessBlock({}, setup.coinbaseKey);
         dmnman.UpdatedBlockTip(chainman.ActiveChain().Tip());
@@ -575,6 +576,7 @@ void FuncDIP3Protx(TestChainSetup& setup)
     bool foundRevived = false;
     for (size_t i = 0; i < 20; i++) {
         auto dmnExpectedPayee = dmnman.GetListAtChainTip().GetMNPayee(chainman.ActiveChain().Tip());
+        BOOST_ASSERT(dmnExpectedPayee);
         if (dmnExpectedPayee->proTxHash == dmnHashes[0]) {
             foundRevived = true;
         }