Workarounds for building with Clang on Ubuntu 22

This commit introduces workarounds for building Concord-BFT with Clang
after the Ubuntu 22 upgrade.

These workarounds include:
- Changing usage of std::optional<::rocksdb::PinnableSlice> to
  std::unique_ptr<::rocksdb::PinnableSlice>, as Clang generates an error
  with this particular template instantiation.
- Removal of the local variable totalVal from the function
  libutt::Factory::randomWallets, as this variable is unused and (with
  -Werror) Clang generates an error for that.

kvbc/include/categorization/blockchain.h

@@ -83,7 +83,7 @@ class Blockchain {
   }
 
   bool hasBlock(BlockId block_id) const {
-    return native_client_->getSlice(detail::BLOCKS_CF, Block::generateKey(block_id)).has_value();
+    return (bool)native_client_->getSlice(detail::BLOCKS_CF, Block::generateKey(block_id));
   }
 
   /////////////////////// State transfer Block chain ///////////////////////
@@ -152,7 +152,7 @@ class Blockchain {
     }
 
     bool hasBlock(BlockId block_id) const {
-      return native_client_->getSlice(detail::ST_CHAIN_CF, Block::generateKey(block_id)).has_value();
+      return (bool)native_client_->getSlice(detail::ST_CHAIN_CF, Block::generateKey(block_id));
     }
 
     void updateLastId(const BlockId id) {

kvbc/src/categorization/block_merkle_category.cpp

@@ -724,7 +724,7 @@ void BlockMerkleCategory::deleteStaleData(uint64_t tree_version, detail::LocalWr
 
   // Create a batch to delete stale keys for this tree version
   auto ser_stale = db_->getSlice(BLOCK_MERKLE_STALE_CF, serialize(TreeVersion{tree_version}));
-  ConcordAssert(ser_stale.has_value());
+  ConcordAssert((bool)ser_stale);
   addStaleKeysToDeleteBatch(*ser_stale, tree_version, batch);
   putLastDeletedTreeVersion(tree_version, batch);
 }
@@ -747,7 +747,7 @@ MerkleBlockValue BlockMerkleCategory::computeRootHash(BlockId block_id,
     // Calculate a new root hash for all keys in the block
     auto versioned_key = serialize(VersionedKey{key, block_id});
     auto value = db_->getSlice(BLOCK_MERKLE_KEYS_CF, versioned_key);
-    ConcordAssert(value.has_value());
+    ConcordAssert((bool)value);
     auto val_hash = hash(*value);
     hasher.update(key.value.data(), key.value.size());
     hasher.update(val_hash.data(), val_hash.size());

kvbc/src/v4blockchain/detail/blockchain.cpp

@@ -265,7 +265,7 @@ bool Blockchain::hasBlock(BlockId block_id) const {
   if ((block_id > last_reachable_block_id_) || (block_id < genesis_block_id_)) {
     return false;
   }
-  return native_client_->getSlice(v4blockchain::detail::BLOCKS_CF, generateKey(block_id)).has_value();
+  return (bool)native_client_->getSlice(v4blockchain::detail::BLOCKS_CF, generateKey(block_id));
 }
 
 }  // namespace concord::kvbc::v4blockchain::detail

kvbc/src/v4blockchain/detail/st_chain.cpp

@@ -34,9 +34,8 @@ StChain::StChain(const std::shared_ptr<concord::storage::rocksdb::NativeClient>&
 /////////// BLOCKS/////////////////////////
 bool StChain::hasBlock(BlockId block_id) const {
   if (last_block_id_ < block_id) return false;
-  return native_client_
-      ->getSlice(v4blockchain::detail::ST_CHAIN_CF, v4blockchain::detail::Blockchain::generateKey(block_id))
-      .has_value();
+  return (bool)native_client_
+      ->getSlice(v4blockchain::detail::ST_CHAIN_CF, v4blockchain::detail::Blockchain::generateKey(block_id));
 }
 
 void StChain::addBlock(const BlockId id, const char* block, const uint32_t blockSize) {

storage/include/rocksdb/native_client.h

@@ -85,9 +85,9 @@ class NativeClient : public std::enable_shared_from_this<NativeClient> {
   std::optional<std::string> get(const std::string &cFamily, const KeySpan &key) const;
   template <typename KeySpan>
   std::optional<std::string> get(const std::string &cFamily, const KeySpan &key, ::rocksdb::ReadOptions ro) const;
-  // Returns nullopt if the key is not found.
+  // Returns null if the key is not found.
   template <typename KeySpan>
-  std::optional<::rocksdb::PinnableSlice> getSlice(const std::string &cFamily, const KeySpan &key) const;
+  std::unique_ptr<::rocksdb::PinnableSlice> getSlice(const std::string &cFamily, const KeySpan &key) const;
   // Deleting a key that doesn't exist is not an error.
   template <typename KeySpan>
   void del(const std::string &cFamily, const KeySpan &key);
@@ -98,9 +98,9 @@ class NativeClient : public std::enable_shared_from_this<NativeClient> {
   // Returns nullopt if the key is not found.
   template <typename KeySpan>
   std::optional<std::string> get(const KeySpan &key) const;
-  // Returns nullopt if the key is not found.
+  // Returns null if the key is not found.
   template <typename KeySpan>
-  std::optional<::rocksdb::PinnableSlice> getSlice(const KeySpan &key) const;
+  std::unique_ptr<::rocksdb::PinnableSlice> getSlice(const KeySpan &key) const;
   // Deleting a key that doesn't exist is not an error.
   template <typename KeySpan>
   void del(const KeySpan &key);

storage/include/rocksdb/native_client.ipp

@@ -107,15 +107,16 @@ std::optional<std::string> NativeClient::get(const std::string &cFamily,
 }
 
 template <typename KeySpan>
-std::optional<::rocksdb::PinnableSlice> NativeClient::getSlice(const std::string &cFamily, const KeySpan &key) const {
-  auto slice = ::rocksdb::PinnableSlice{};
+std::unique_ptr<::rocksdb::PinnableSlice> NativeClient::getSlice(const std::string &cFamily, const KeySpan &key) const {
+  auto slice = std::make_unique<::rocksdb::PinnableSlice>();
   auto s =
-      client_->dbInstance_->Get(::rocksdb::ReadOptions{}, columnFamilyHandle(cFamily), detail::toSlice(key), &slice);
+      client_->dbInstance_->Get(::rocksdb::ReadOptions{}, columnFamilyHandle(cFamily), detail::toSlice(key),
+      slice.get());
   if (s.IsNotFound()) {
-    return std::nullopt;
+    return std::unique_ptr<::rocksdb::PinnableSlice>(nullptr);
   }
   detail::throwOnError("get() failed"sv, std::move(s));
-  return std::move(slice);
+  return slice;
 }
 
 template <typename KeySpan>
@@ -135,7 +136,7 @@ std::optional<std::string> NativeClient::get(const KeySpan &key) const {
 }
 
 template <typename KeySpan>
-std::optional<::rocksdb::PinnableSlice> NativeClient::getSlice(const KeySpan &key) const {
+std::unique_ptr<::rocksdb::PinnableSlice> NativeClient::getSlice(const KeySpan &key) const {
   return getSlice(defaultColumnFamily(), key);
 }
 

utt/libutt/include/utt/Factory.h

@@ -76,11 +76,9 @@ class Factory {
 
       // issue some random 'normal' coins to this user
       Coin prevCoin;
-      size_t totalVal = 0;
       for (size_t k = 0; k < numCoins; k++) {
         // ...of value less than or equal to the allowed max coin value
         size_t val = static_cast<size_t>(rand()) % maxDenom + 1;
-        totalVal += val;
 
         // ...and everything else random
         Coin c = Factory::mintRandomCoin(Coin::NormalType(), val, ask);