Replace boost::optional with std::optional

src/chain.h

@@ -12,6 +12,7 @@
 #include "tinyformat.h"
 #include "uint256.h"
 
+#include <optional>
 #include <vector>
 
 static const int SPROUT_VALUE_VERSION = 1001400;
@@ -228,7 +229,7 @@ class CBlockIndex
     //! Branch ID corresponding to the consensus rules used to validate this block.
     //! Only cached if block validity is BLOCK_VALID_CONSENSUS.
     //! Persisted at each activation height, memory-only for intervening blocks.
-    boost::optional<uint32_t> nCachedBranchId;
+    std::optional<uint32_t> nCachedBranchId;
 
     //! The anchor for the tree state up to the start of this block
     uint256 hashSproutAnchor;
@@ -237,22 +238,22 @@ class CBlockIndex
     uint256 hashFinalSproutRoot;
 
     //! Change in value held by the Sprout circuit over this block.
-    //! Will be boost::none for older blocks on old nodes until a reindex has taken place.
-    boost::optional<CAmount> nSproutValue;
+    //! Will be std::nullopt for older blocks on old nodes until a reindex has taken place.
+    std::optional<CAmount> nSproutValue;
 
     //! (memory only) Total value held by the Sprout circuit up to and including this block.
-    //! Will be boost::none for on old nodes until a reindex has taken place.
-    //! Will be boost::none if nChainTx is zero.
-    boost::optional<CAmount> nChainSproutValue;
+    //! Will be std::nullopt for on old nodes until a reindex has taken place.
+    //! Will be std::nullopt if nChainTx is zero.
+    std::optional<CAmount> nChainSproutValue;
 
     //! Change in value held by the Sapling circuit over this block.
-    //! Not a boost::optional because this was added before Sapling activated, so we can
+    //! Not a std::optional because this was added before Sapling activated, so we can
     //! rely on the invariant that every block before this was added had nSaplingValue = 0.
     CAmount nSaplingValue;
 
     //! (memory only) Total value held by the Sapling circuit up to and including this block.
-    //! Will be boost::none if nChainTx is zero.
-    boost::optional<CAmount> nChainSaplingValue;
+    //! Will be std::nullopt if nChainTx is zero.
+    std::optional<CAmount> nChainSaplingValue;
 
     //! Root of the Sapling commitment tree as of the end of this block.
     //!
@@ -295,14 +296,14 @@ class CBlockIndex
         nTx = 0;
         nChainTx = 0;
         nStatus = 0;
-        nCachedBranchId = boost::none;
+        nCachedBranchId = std::nullopt;
         hashSproutAnchor = uint256();
         hashFinalSproutRoot = uint256();
         nSequenceId = 0;
-        nSproutValue = boost::none;
-        nChainSproutValue = boost::none;
+        nSproutValue = std::nullopt;
+        nChainSproutValue = std::nullopt;
         nSaplingValue = 0;
-        nChainSaplingValue = boost::none;
+        nChainSaplingValue = std::nullopt;
 
         nVersion       = 0;
         hashMerkleRoot = uint256();

src/chainparams.cpp

@@ -13,6 +13,7 @@
 #include "utilstrencodings.h"
 
 #include <assert.h>
+#include <optional>
 #include <variant>
 
 #include <boost/assign/list_of.hpp>
@@ -104,7 +105,7 @@ class CMainParams : public CChainParams {
         consensus.nPowMaxAdjustUp = 16; // 16% adjustment up
         consensus.nPreBlossomPowTargetSpacing = Consensus::PRE_BLOSSOM_POW_TARGET_SPACING;
         consensus.nPostBlossomPowTargetSpacing = Consensus::POST_BLOSSOM_POW_TARGET_SPACING;
-        consensus.nPowAllowMinDifficultyBlocksAfterHeight = boost::none;
+        consensus.nPowAllowMinDifficultyBlocksAfterHeight = std::nullopt;
         consensus.vUpgrades[Consensus::BASE_SPROUT].nProtocolVersion = 170002;
         consensus.vUpgrades[Consensus::BASE_SPROUT].nActivationHeight =
             Consensus::NetworkUpgrade::ALWAYS_ACTIVE;

src/consensus/funding.cpp

@@ -48,9 +48,9 @@ std::set<FundingStreamElement> GetActiveFundingStreamElements(
         // in the definition of vFundingStreams.
         auto fs = params.vFundingStreams[idx];
         // Funding period is [startHeight, endHeight)
-        if (fs && nHeight >= fs.get().GetStartHeight() && nHeight < fs.get().GetEndHeight()) {
+        if (fs && nHeight >= fs.value().GetStartHeight() && nHeight < fs.value().GetEndHeight()) {
             requiredElements.insert(std::make_pair(
-                fs.get().RecipientAddress(params, nHeight),
+                fs.value().RecipientAddress(params, nHeight),
                 FundingStreamInfo[idx].Value(blockSubsidy)));
         }
     }
@@ -64,7 +64,7 @@ std::vector<FSInfo> GetActiveFundingStreams(
     std::vector<FSInfo> activeStreams;
     for (uint32_t idx = Consensus::FIRST_FUNDING_STREAM; idx < Consensus::MAX_FUNDING_STREAMS; idx++) {
         auto fs = params.vFundingStreams[idx];
-        if (fs && nHeight >= fs.get().GetStartHeight() && nHeight < fs.get().GetEndHeight()) {
+        if (fs && nHeight >= fs.value().GetStartHeight() && nHeight < fs.value().GetEndHeight()) {
             activeStreams.push_back(FundingStreamInfo[idx]);
         }
     }

src/consensus/params.h

@@ -11,10 +11,9 @@
 #include "key_constants.h"
 #include <zcash/address/sapling.hpp>
 
+#include <optional>
 #include <variant>
 
-#include <boost/optional.hpp>
-
 namespace Consensus {
 
 // Early declaration to ensure it is accessible.
@@ -80,7 +79,7 @@ struct NetworkUpgrade {
      * scrutiny than regular releases. nMinimumChainWork MUST be set to at least the chain
      * work of this block, otherwise this detection will have false positives.
      */
-    boost::optional<uint256> hashActivationBlock;
+    std::optional<uint256> hashActivationBlock;
 };
 
 typedef std::variant<libzcash::SaplingPaymentAddress, CScript> FundingStreamAddress;
@@ -211,7 +210,7 @@ struct Params {
     NetworkUpgrade vUpgrades[MAX_NETWORK_UPGRADES];
 
     int nFundingPeriodLength;
-    boost::optional<FundingStream> vFundingStreams[MAX_FUNDING_STREAMS];
+    std::optional<FundingStream> vFundingStreams[MAX_FUNDING_STREAMS];
     void AddZIP207FundingStream(
         const KeyConstants& keyConstants,
         FundingStreamIndex idx,
@@ -263,7 +262,7 @@ struct Params {
     unsigned int nEquihashN = 0;
     unsigned int nEquihashK = 0;
     uint256 powLimit;
-    boost::optional<uint32_t> nPowAllowMinDifficultyBlocksAfterHeight;
+    std::optional<uint32_t> nPowAllowMinDifficultyBlocksAfterHeight;
     int64_t nPowAveragingWindow;
     int64_t nPowMaxAdjustDown;
     int64_t nPowMaxAdjustUp;

src/consensus/upgrades.cpp

@@ -140,9 +140,9 @@ bool IsActivationHeightForAnyUpgrade(
     return false;
 }
 
-boost::optional<int> NextEpoch(int nHeight, const Consensus::Params& params) {
+std::optional<int> NextEpoch(int nHeight, const Consensus::Params& params) {
     if (nHeight < 0) {
-        return boost::none;
+        return std::nullopt;
     }
 
     // Sprout is never pending
@@ -152,16 +152,16 @@ boost::optional<int> NextEpoch(int nHeight, const Consensus::Params& params) {
         }
     }
 
-    return boost::none;
+    return std::nullopt;
 }
 
-boost::optional<int> NextActivationHeight(
+std::optional<int> NextActivationHeight(
     int nHeight,
     const Consensus::Params& params)
 {
     auto idx = NextEpoch(nHeight, params);
     if (idx) {
-        return params.vUpgrades[idx.get()].nActivationHeight;
+        return params.vUpgrades[idx.value()].nActivationHeight;
     }
-    return boost::none;
+    return std::nullopt;
 }

src/consensus/upgrades.h

@@ -7,7 +7,7 @@
 
 #include "consensus/params.h"
 
-#include <boost/optional.hpp>
+#include <optional>
 
 enum UpgradeState {
     UPGRADE_DISABLED,
@@ -83,15 +83,15 @@ bool IsActivationHeightForAnyUpgrade(
 
 /**
  * Returns the index of the next upgrade after the given block height, or
- * boost::none if there are no more known upgrades.
+ * std::nullopt if there are no more known upgrades.
  */
-boost::optional<int> NextEpoch(int nHeight, const Consensus::Params& params);
+std::optional<int> NextEpoch(int nHeight, const Consensus::Params& params);
 
 /**
  * Returns the activation height for the next upgrade after the given block height,
- * or boost::none if there are no more known upgrades.
+ * or std::nullopt if there are no more known upgrades.
  */
-boost::optional<int> NextActivationHeight(
+std::optional<int> NextActivationHeight(
     int nHeight,
     const Consensus::Params& params);
 

src/crypto/equihash.cpp

@@ -24,10 +24,9 @@
 
 #include <algorithm>
 #include <iostream>
+#include <optional>
 #include <stdexcept>
 
-#include <boost/optional.hpp>
-
 static EhSolverCancelledException solver_cancelled;
 
 eh_HashState::eh_HashState(
@@ -657,7 +656,7 @@ bool Equihash<N,K>::OptimisedSolve(const eh_HashState& base_state,
         size_t hashLen;
         size_t lenIndices;
         unsigned char tmpHash[HashOutput];
-        std::vector<boost::optional<std::vector<FullStepRow<FinalFullWidth>>>> X;
+        std::vector<std::optional<std::vector<FullStepRow<FinalFullWidth>>>> X;
         X.reserve(K+1);
 
         // 3) Repeat steps 1 and 2 for each partial index
@@ -675,7 +674,7 @@ bool Equihash<N,K>::OptimisedSolve(const eh_HashState& base_state,
                                  N/8, HashLength, CollisionBitLength, newIndex);
                 if (cancelled(PartialGeneration)) throw solver_cancelled;
             }
-            boost::optional<std::vector<FullStepRow<FinalFullWidth>>> ic = icv;
+            std::optional<std::vector<FullStepRow<FinalFullWidth>>> ic = icv;
 
             // 2a) For each pair of lists:
             hashLen = HashLength;
@@ -700,7 +699,7 @@ bool Equihash<N,K>::OptimisedSolve(const eh_HashState& base_state,
                         if (ic->size() == 0)
                             goto invalidsolution;
 
-                        X[r] = boost::none;
+                        X[r] = std::nullopt;
                         hashLen -= CollisionByteLength;
                         lenIndices *= 2;
                         rti = lti;

src/experimental_features.cpp

@@ -12,7 +12,7 @@ bool fExperimentalPaymentDisclosure = false;
 bool fExperimentalInsightExplorer = false;
 bool fExperimentalLightWalletd = false;
 
-boost::optional<std::string> InitExperimentalMode()
+std::optional<std::string> InitExperimentalMode()
 {
     auto fExperimentalMode = GetBoolArg("-experimentalfeatures", false);
     fExperimentalDeveloperEncryptWallet = GetBoolArg("-developerencryptwallet", false);
@@ -35,7 +35,7 @@ boost::optional<std::string> InitExperimentalMode()
             return _("Light Walletd requires -experimentalfeatures.");
         }
     }
-    return boost::none;
+    return std::nullopt;
 }
 
 std::vector<std::string> GetExperimentalFeatures()

src/experimental_features.h

@@ -2,15 +2,15 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or https://www.opensource.org/licenses/mit-license.php .
 
+#include <optional>
 #include <string>
 #include <vector>
-#include <boost/optional.hpp>
 
 extern bool fExperimentalDeveloperEncryptWallet;
 extern bool fExperimentalDeveloperSetPoolSizeZero;
 extern bool fExperimentalPaymentDisclosure;
 extern bool fExperimentalInsightExplorer;
 extern bool fExperimentalLightWalletd;
 
-boost::optional<std::string> InitExperimentalMode();
+std::optional<std::string> InitExperimentalMode();
 std::vector<std::string> GetExperimentalFeatures();

src/gtest/test_checktransaction.cpp

@@ -1138,7 +1138,7 @@ TEST(ChecktransactionTests, HeartwoodAcceptsShieldedCoinbase) {
     auto output = OutputDescriptionInfo(ovk, note, {{0xF6}});
 
     auto ctx = librustzcash_sapling_proving_ctx_init();
-    auto odesc = output.Build(ctx).get();
+    auto odesc = output.Build(ctx).value();
     librustzcash_sapling_proving_ctx_free(ctx);
 
     CMutableTransaction mtx = GetValidTransaction();
@@ -1244,7 +1244,7 @@ TEST(ChecktransactionTests, HeartwoodEnforcesSaplingRulesOnShieldedCoinbase) {
 
     // Add a Sapling output.
     auto ctx = librustzcash_sapling_proving_ctx_init();
-    auto odesc = output.Build(ctx).get();
+    auto odesc = output.Build(ctx).value();
     librustzcash_sapling_proving_ctx_free(ctx);
     mtx.vShieldedOutput.push_back(odesc);
 

src/gtest/test_foundersreward.cpp

@@ -105,8 +105,8 @@ void checkNumberOfUniqueAddresses(int nUnique) {
 int GetMaxFundingStreamHeight(const Consensus::Params& params) {
     int result = 0;
     for (auto fs : params.vFundingStreams) {
-        if (fs && result < fs.get().GetEndHeight() - 1) {
-            result = fs.get().GetEndHeight() - 1;
+        if (fs && result < fs.value().GetEndHeight() - 1) {
+            result = fs.value().GetEndHeight() - 1;
         }
     }
 

src/gtest/test_mempoollimit.cpp

@@ -94,13 +94,13 @@ TEST(MempoolLimitTests, WeightedTxTreeCheckSizeAfterDropping)
         tree.add(WeightedTxInfo(TX_ID2, TxWeight(MIN_TX_COST, MIN_TX_COST)));
         EXPECT_EQ(8000, tree.getTotalWeight().cost);
         EXPECT_EQ(8000, tree.getTotalWeight().evictionWeight);
-        EXPECT_FALSE(tree.maybeDropRandom().is_initialized());
+        EXPECT_FALSE(tree.maybeDropRandom().has_value());
         tree.add(WeightedTxInfo(TX_ID3, TxWeight(MIN_TX_COST, MIN_TX_COST + LOW_FEE_PENALTY)));
         EXPECT_EQ(12000, tree.getTotalWeight().cost);
         EXPECT_EQ(12000 + LOW_FEE_PENALTY, tree.getTotalWeight().evictionWeight);
-        boost::optional<uint256> drop = tree.maybeDropRandom();
-        ASSERT_TRUE(drop.is_initialized());
-        uint256 txid = drop.get();
+        auto drop = tree.maybeDropRandom();
+        ASSERT_TRUE(drop.has_value());
+        uint256 txid = drop.value();
         testedDropping.insert(txid);
         // Do not continue to test if a particular trial fails
         ASSERT_EQ(8000, tree.getTotalWeight().cost);