Add Python 3.8 testing (take 2)

.circleci/config.yml

@@ -168,6 +168,37 @@ jobs:
         environment:
           TOXENV: py37-lint
 
+  py38-core:
+    <<: *common
+    docker:
+      - image: circleci/python:3.8
+        environment:
+          TOXENV: py38-core
+  py38-database:
+    <<: *common
+    docker:
+      - image: circleci/python:3.8
+        environment:
+          TOXENV: py38-database
+  py38-transactions:
+    <<: *common
+    docker:
+      - image: circleci/python:3.8
+        environment:
+          TOXENV: py38-transactions
+  py38-vm:
+    <<: *common
+    docker:
+      - image: circleci/python:3.8
+        environment:
+          TOXENV: py38-vm
+  py38-lint:
+    <<: *common
+    docker:
+      - image: circleci/python:3.8
+        environment:
+          TOXENV: py38-lint
+
 workflows:
   version: 2
   test:
@@ -184,12 +215,17 @@ workflows:
       - py36-native-blockchain-transition
       - py36-vm
       - py37-vm
+      - py38-vm
       - py36-core
       - py37-core
+      - py38-core
       - py36-transactions
       - py37-transactions
+      - py38-transactions
       - py36-database
       - py37-database
+      - py38-database
       - py36-docs
       - py36-lint
       - py37-lint
+      - py38-lint

eth/_utils/transactions.py

@@ -136,8 +136,8 @@ def calculate_intrinsic_gas(
     else:
         create_cost = 0
     return (
-        gas_schedule.gas_tx +
-        num_zero_bytes * gas_schedule.gas_txdatazero +
-        num_non_zero_bytes * gas_schedule.gas_txdatanonzero +
-        create_cost
+        gas_schedule.gas_tx
+        + num_zero_bytes * gas_schedule.gas_txdatazero
+        + num_non_zero_bytes * gas_schedule.gas_txdatanonzero
+        + create_cost
     )

eth/abc.py

@@ -20,7 +20,6 @@
     TypeVar,
     Union,
 )
-from uuid import UUID
 
 import rlp
 
@@ -886,9 +885,9 @@ def __call__(self, computation: 'ComputationAPI') -> None:
     def as_opcode(cls: Type[T],
                   logic_fn: Callable[['ComputationAPI'], None],
                   mnemonic: str,
-                  gas_cost: int) -> Type[T]:
+                  gas_cost: int) -> T:
         """
-        Class factory method for turning vanilla functions into Opcode classes.
+        Class factory method for turning vanilla functions into Opcodes.
         """
         ...
 
@@ -1769,6 +1768,16 @@ def state_root(self) -> Hash32:
         """
         ...
 
+    @state_root.setter
+    def state_root(self, value: Hash32) -> None:
+        """
+        Force-set the state root hash.
+        """
+        # See: https://github.com/python/mypy/issues/4165
+        # Since we can't also decorate this with abstract method we want to be
+        # sure that the setter doesn't actually get used as a noop.
+        raise NotImplementedError
+
     @abstractmethod
     def has_root(self, state_root: bytes) -> bool:
         """
@@ -1935,6 +1944,22 @@ def commit(self, checkpoint: JournalDBCheckpoint) -> None:
         """
         ...
 
+    @abstractmethod
+    def lock_changes(self) -> None:
+        """
+        Locks in changes across all accounts' storage databases.
+
+        This is typically used at the end of a transaction, to make sure that
+        a revert doesn't roll back through the previous transaction, and to
+        be able to look up the "original" value of any account storage, where
+        "original" is the beginning of a transaction (instead of the beginning
+        of a block).
+
+        See :meth:`eth.abc.AccountStorageDatabaseAPI.lock_changes` for
+        what is called on each account's storage database.
+        """
+        ...
+
     @abstractmethod
     def make_state_root(self) -> Hash32:
         """
@@ -2275,7 +2300,7 @@ def account_is_empty(self, address: Address) -> bool:
     # Access self._chaindb
     #
     @abstractmethod
-    def snapshot(self) -> Tuple[Hash32, UUID]:
+    def snapshot(self) -> Tuple[Hash32, JournalDBCheckpoint]:
         """
         Perform a full snapshot of the current state.
 
@@ -2285,14 +2310,14 @@ def snapshot(self) -> Tuple[Hash32, UUID]:
         ...
 
     @abstractmethod
-    def revert(self, snapshot: Tuple[Hash32, UUID]) -> None:
+    def revert(self, snapshot: Tuple[Hash32, JournalDBCheckpoint]) -> None:
         """
         Revert the VM to the state at the snapshot
         """
         ...
 
     @abstractmethod
-    def commit(self, snapshot: Tuple[Hash32, UUID]) -> None:
+    def commit(self, snapshot: Tuple[Hash32, JournalDBCheckpoint]) -> None:
         """
         Commit the journal to the point where the snapshot was taken.  This
         merges in any changes that were recorded since the snapshot.
@@ -2481,6 +2506,7 @@ class VirtualMachineAPI(ConfigurableAPI):
     def __init__(self,
                  header: BlockHeaderAPI,
                  chaindb: ChainDatabaseAPI,
+                 chain_context: ChainContextAPI,
                  consensus_context: ConsensusContextAPI) -> None:
         """
         Initialize the virtual machine.

eth/chains/base.py

@@ -244,8 +244,8 @@ def from_genesis(cls,
             # the computed state from the initialized state database.
             raise ValidationError(
                 "The provided genesis state root does not match the computed "
-                f"genesis state root.  Got {state.state_root}.  "
-                f"Expected {genesis_params['state_root']}"
+                f"genesis state root.  Got {state.state_root!r}.  "
+                f"Expected {genesis_params['state_root']!r}"
             )
 
         genesis_header = BlockHeader(**genesis_params)
@@ -463,8 +463,8 @@ def import_block(self,
         except HeaderNotFound:
             raise ValidationError(
                 f"Attempt to import block #{block.number}.  "
-                f"Cannot import block {block.hash} before importing "
-                f"its parent block at {block.header.parent_hash}"
+                f"Cannot import block {block.hash!r} before importing "
+                f"its parent block at {block.header.parent_hash!r}"
             )
 
         base_header_for_import = self.create_header_from_parent(parent_header)

eth/consensus/clique/_utils.py

@@ -139,10 +139,10 @@ def validate_header_integrity(header: BlockHeaderAPI, epoch_length: int) -> None
         )
 
     if header.nonce != NONCE_AUTH and header.nonce != NONCE_DROP:
-        raise ValidationError(f"Invalid nonce: {header.nonce}")
+        raise ValidationError(f"Invalid nonce: {header.nonce!r}")
 
     if at_checkpoint and header.nonce != NONCE_DROP:
-        raise ValidationError(f"Invalid checkpoint nonce: {header.nonce}")
+        raise ValidationError(f"Invalid checkpoint nonce: {header.nonce!r}")
 
     if len(header.extra_data) < VANITY_LENGTH:
         raise ValidationError("Missing vanity bytes in extra data")
@@ -159,7 +159,7 @@ def validate_header_integrity(header: BlockHeaderAPI, epoch_length: int) -> None
         raise ValidationError("Checkpoint header must contain list of signers")
 
     if header.mix_hash != ZERO_HASH32:
-        raise ValidationError(f"Invalid mix hash: {header.mix_hash}")
+        raise ValidationError(f"Invalid mix hash: {header.mix_hash!r}")
 
     if header.uncles_hash != EMPTY_UNCLE_HASH:
         raise ValidationError(f"Invalid uncle hash: {header.uncle_hash}")

eth/consensus/clique/datatypes.py

@@ -46,7 +46,7 @@ def validate_for(self,
         if not signer_is_kicked and not signer_is_nominated:
             raise ValidationError(
                 "Must either kick an existing signer or nominate a new signer"
-                f"Subject: {subject} Current signers: {signers}"
+                f"Subject: {subject!r} Current signers: {signers}"
             )
 
 

eth/consensus/clique/snapshot_manager.py

@@ -182,7 +182,7 @@ def create_snapshot_for(self,
             try:
                 new_snapshot = self.get_snapshot(
                     current_header.block_number, current_header.parent_hash)
-            except SnapshotNotFound as e:
+            except SnapshotNotFound:
                 current_header = self._lookup_header(current_header.parent_hash, cached_parents)
 
                 if is_checkpoint(current_header.block_number, self._epoch_length):
@@ -225,16 +225,16 @@ def get_snapshot(self, block_number: int, block_hash: Hash32) -> Snapshot:
                 # Otherwise, we can retrieve it on the fly
                 header = self._chain_db.get_block_header_by_hash(block_hash)
             except HeaderNotFound:
-                raise SnapshotNotFound(f"Can not get snapshot for {block_hash} at {block_number}")
+                raise SnapshotNotFound(f"Can not get snapshot for {block_hash!r} at {block_number}")
             else:
                 if header.block_number != block_number:
                     raise SnapshotNotFound(
-                        f"Can not get snapshot for {block_hash} at {block_number}"
+                        f"Can not get snapshot for {block_hash!r} at {block_number}"
                     )
                 else:
                     return self._create_snapshot_from_checkpoint_header(header)
 
-        raise SnapshotNotFound(f"Can not get snapshot for {block_hash} at {block_number}")
+        raise SnapshotNotFound(f"Can not get snapshot for {block_hash!r} at {block_number}")
 
     def add_snapshot(self, mutable_snapshot: MutableSnapshot) -> Snapshot:
         """
@@ -261,8 +261,8 @@ def get_snapshot_from_db(self, block_hash: Hash32) -> Snapshot:
             encoded_key = self._chain_db.db[key]
         except KeyError as e:
             raise SnapshotNotFound(
-                f"Can not get on-disk snapshot for {block_hash}"
-            )
+                f"Can not get on-disk snapshot for {block_hash!r}"
+            ) from e
         else:
             return decode_snapshot(encoded_key)
 

eth/db/chain.py

@@ -86,7 +86,7 @@ def get_block_uncles(self, uncles_hash: Hash32) -> Tuple[BlockHeaderAPI, ...]:
             encoded_uncles = self.db[uncles_hash]
         except KeyError:
             raise HeaderNotFound(
-                f"No uncles found for hash {uncles_hash}"
+                f"No uncles found for hash {uncles_hash!r}"
             )
         else:
             return tuple(rlp.decode(encoded_uncles, sedes=rlp.sedes.CountableList(BlockHeader)))
@@ -141,16 +141,16 @@ def persist_unexecuted_block(self,
 
         if tx_root_hash != block.header.transaction_root:
             raise ValidationError(
-                f"Block's transaction_root ({block.header.transaction_root}) "
-                f"does not match expected value: {tx_root_hash}"
+                f"Block's transaction_root ({block.header.transaction_root!r}) "
+                f"does not match expected value: {tx_root_hash!r}"
             )
 
         receipt_root_hash, receipt_kv_nodes = make_trie_root_and_nodes(receipts)
 
         if receipt_root_hash != block.header.receipt_root:
             raise ValidationError(
-                f"Block's receipt_root ({block.header.receipt_root}) "
-                f"does not match expected value: {receipt_root_hash}"
+                f"Block's receipt_root ({block.header.receipt_root!r}) "
+                f"does not match expected value: {receipt_root_hash!r}"
             )
 
         with self.db.atomic_batch() as db:

eth/db/header.py

@@ -79,22 +79,23 @@ def _update_header_chain_gaps(
             cls,
             db: DatabaseAPI,
             persisted_header: BlockHeaderAPI,
-            base_gaps: ChainGaps = None) -> GapInfo:
+            base_gaps: ChainGaps = None
+    ) -> GapInfo:
 
-            # If we make many updates in a row, we can avoid reloading the integrity info by
-            # continuously caching it and providing it as a parameter to this API
-            if base_gaps is None:
-                base_gaps = cls._get_header_chain_gaps(db)
+        # If we make many updates in a row, we can avoid reloading the integrity info by
+        # continuously caching it and providing it as a parameter to this API
+        if base_gaps is None:
+            base_gaps = cls._get_header_chain_gaps(db)
 
-            gap_change, gaps = fill_gap(persisted_header.block_number, base_gaps)
+        gap_change, gaps = fill_gap(persisted_header.block_number, base_gaps)
 
-            if gap_change is not GapChange.NoChange:
-                db.set(
-                    SchemaV1.make_header_chain_gaps_lookup_key(),
-                    rlp.encode(gaps, sedes=chain_gaps)
-                )
+        if gap_change is not GapChange.NoChange:
+            db.set(
+                SchemaV1.make_header_chain_gaps_lookup_key(),
+                rlp.encode(gaps, sedes=chain_gaps)
+            )
 
-            return gap_change, gaps
+        return gap_change, gaps
 
     #
     # Canonical Chain API
@@ -260,7 +261,7 @@ def _persist_checkpoint_header(
                     # True parent should have already been canonicalized during
                     #   _set_as_canonical_chain_head()
                     raise ValidationError(
-                        f"Why was a non-matching parent header {parent_hash} left as canonical "
+                        f"Why was a non-matching parent header {parent_hash!r} left as canonical "
                         f"after _set_as_canonical_chain_head() and {true_parent} is available?"
                     )
 

eth/precompiles/modexp.py

@@ -34,8 +34,8 @@ def _compute_adjusted_exponent_length(exponent_length: int,
     else:
         first_32_bytes_as_int = big_endian_to_int(first_32_exponent_bytes)
         return (
-            8 * (exponent_length - 32) +
-            get_highest_bit_index(first_32_bytes_as_int)
+            8 * (exponent_length - 32)
+            + get_highest_bit_index(first_32_bytes_as_int)
         )
 
 
@@ -78,9 +78,9 @@ def _compute_modexp_gas_fee(data: bytes) -> int:
     complexity = _compute_complexity(max(modulus_length, base_length))
 
     gas_fee = (
-        complexity *
-        max(adjusted_exponent_length, 1) //
-        constants.GAS_MOD_EXP_QUADRATIC_DENOMINATOR
+        complexity
+        * max(adjusted_exponent_length, 1)
+        // constants.GAS_MOD_EXP_QUADRATIC_DENOMINATOR
     )
     return gas_fee
 

eth/tools/fixtures/helpers.py

@@ -76,13 +76,13 @@ def verify_state(expected_state: AccountState, state: StateAPI) -> None:
             if field == 'balance':
                 error_messages.append(
                     f"{to_normalized_address(account)}(balance) | "
-                    f"Actual: {actual_value} | Expected: {expected_value} | "
+                    f"Actual: {actual_value!r} | Expected: {expected_value!r} | "
                     f"Delta: {cast(int, actual_value) - cast(int, expected_value)}"
                 )
             else:
                 error_messages.append(
                     f"{to_normalized_address(account)}({field}) | "
-                    f"Actual: {actual_value} | Expected: {expected_value}"
+                    f"Actual: {actual_value!r} | Expected: {expected_value!r}"
                 )
         raise AssertionError(
             f"State DB did not match expected state on {len(error_messages)} values:{new_line}"

eth/validation.py

@@ -111,7 +111,7 @@ def validate_lt(value: int, maximum: int, title: str="Value") -> None:
 def validate_canonical_address(value: Address, title: str="Value") -> None:
     if not isinstance(value, bytes) or not len(value) == 20:
         raise ValidationError(
-            f"{title} {value} is not a valid canonical address"
+            f"{title} {value!r} is not a valid canonical address"
         )