ABC,eth/vm/state: replace occurences of UUID with JournalDBCheckpoint.

Silences errors:

    eth/vm/state.py:165: error: Incompatible return value type (got "Tuple[Hash32, JournalDBCheckpoint]", expected "Tuple[Hash32, UUID]")
    eth/vm/state.py:173: error: Argument 1 to "discard" of "AccountDatabaseAPI" has incompatible type "UUID"; expected "JournalDBCheckpoint"
    eth/vm/state.py:177: error: Argument 1 to "commit" of "AccountDatabaseAPI" has incompatible type "UUID"; expected "JournalDBCheckpoint"

Author: veox

eth/abc.py

@@ -20,7 +20,6 @@
     TypeVar,
     Union,
 )
-from uuid import UUID
 
 import rlp
 
@@ -2301,7 +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.
 
@@ -2311,14 +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.

eth/vm/state.py

@@ -4,7 +4,6 @@
     Tuple,
     Type,
 )
-from uuid import UUID
 
 from eth_typing import (
     Address,
@@ -32,6 +31,7 @@
 from eth.constants import (
     MAX_PREV_HEADER_DEPTH,
 )
+from eth.typing import JournalDBCheckpoint
 from eth._utils.datatypes import (
     Configurable,
 )
@@ -161,18 +161,18 @@ def account_is_empty(self, address: Address) -> bool:
     #
     # Access self._chaindb
     #
-    def snapshot(self) -> Tuple[Hash32, UUID]:
+    def snapshot(self) -> Tuple[Hash32, JournalDBCheckpoint]:
         return self.state_root, self._account_db.record()
 
-    def revert(self, snapshot: Tuple[Hash32, UUID]) -> None:
+    def revert(self, snapshot: Tuple[Hash32, JournalDBCheckpoint]) -> None:
         state_root, account_snapshot = snapshot
 
         # first revert the database state root.
         self._account_db.state_root = state_root
         # now roll the underlying database back
         self._account_db.discard(account_snapshot)
 
-    def commit(self, snapshot: Tuple[Hash32, UUID]) -> None:
+    def commit(self, snapshot: Tuple[Hash32, JournalDBCheckpoint]) -> None:
         _, account_snapshot = snapshot
         self._account_db.commit(account_snapshot)