Move and reuse StaticMethod helper tighten type support

Author: cburgdorf

eth/chains/base.py

@@ -20,6 +20,8 @@
     Type,
     TYPE_CHECKING,
     Union,
+    TypeVar,
+    Generic,
 )
 
 import logging
@@ -72,8 +74,9 @@
     BaseUnsignedTransaction,
 )
 
-from eth.typing import (
+from eth.typing import (  # noqa: F401
     AccountState,
+    StaticMethod,
 )
 
 from eth.utils.spoof import (
@@ -99,7 +102,7 @@
     validate_vm_configuration,
 )
 from eth.vm.computation import BaseComputation
-from eth.vm.state import BaseState      # noqa: F401
+from eth.vm.state import BaseState  # noqa: F401
 
 from eth._warnings import catch_and_ignore_import_warning
 with catch_and_ignore_import_warning():
@@ -335,7 +338,7 @@ class Chain(BaseChain):
     current block number.
     """
     logger = logging.getLogger("eth.chain.chain.Chain")
-    gas_estimator = None  # type: Callable[[BaseState, BaseTransaction], int]
+    gas_estimator = None  # type: StaticMethod[Callable[[BaseState, Union[BaseTransaction, SpoofTransaction]], int]]  # noqa: E501
 
     chaindb_class = ChainDB  # type: Type[BaseChainDB]
 
@@ -349,8 +352,8 @@ def __init__(self, base_db: BaseAtomicDB) -> None:
 
         self.chaindb = self.get_chaindb_class()(base_db)
         self.headerdb = HeaderDB(base_db)
-        if self.gas_estimator is None:                  # type: ignore
-            self.gas_estimator = get_gas_estimator()    # type: ignore
+        if self.gas_estimator is None:
+            self.gas_estimator = get_gas_estimator()
 
     #
     # Helpers
@@ -648,7 +651,7 @@ def estimate_gas(
         if at_header is None:
             at_header = self.get_canonical_head()
         with self.get_vm(at_header).state_in_temp_block() as state:
-            return self.gas_estimator(state, transaction)   # type: ignore
+            return self.gas_estimator(state, transaction)
 
     def import_block(self,
                      block: BaseBlock,

eth/estimators/__init__.py

@@ -1,19 +1,30 @@
 import os
 from typing import (
     Callable,
-    cast
+    cast,
+    Union,
 )
 
-
-from eth_utils import import_string
-
-from eth.rlp.transactions import BaseTransaction
-from eth.vm.state import BaseState
+from eth.rlp.transactions import (
+    BaseTransaction,
+)
+from eth.utils.module_loading import (
+    import_string,
+)
+from eth.utils.spoof import (
+    SpoofTransaction,
+)
+from eth.vm.state import (
+    BaseState,
+)
 
 
-def get_gas_estimator() -> Callable[[BaseState, BaseTransaction], int]:
+def get_gas_estimator() -> Callable[[BaseState, Union[BaseTransaction, SpoofTransaction]], int]:
     import_path = os.environ.get(
         'GAS_ESTIMATOR_BACKEND_FUNC',
         'eth.estimators.gas.binary_gas_search_intrinsic_tolerance',
     )
-    return cast(Callable[[BaseState, BaseTransaction], int], import_string(import_path))
+    return cast(
+        Callable[[BaseState, Union[BaseTransaction, SpoofTransaction]], int],
+        import_string(import_path)
+    )

eth/typing.py

@@ -2,11 +2,13 @@
     Any,
     Callable,
     Dict,
+    Generic,
     Iterable,
     List,
     NewType,
     Tuple,
     Union,
+    TypeVar,
 )
 
 from eth_typing import (
@@ -52,3 +54,18 @@
 VRS = NewType("VRS", Tuple[int, int, int])
 
 IntConvertible = Union[int, bytes, HexStr, str]
+
+
+TFunc = TypeVar('TFunc')
+
+
+class StaticMethod(Generic[TFunc]):
+    """
+    A property class purely to convince mypy to let us assign a function to an
+    instance variable. See more at: https://github.com/python/mypy/issues/708#issuecomment-405812141
+    """
+    def __get__(self, oself: Any, owner: Any) -> TFunc:
+        return self._func
+
+    def __set__(self, oself: Any, value: TFunc) -> None:
+        self._func = value

trinity/utils/datastructures.py

@@ -44,29 +44,20 @@
     pipe,
 )
 
+from eth.typing import (
+    StaticMethod,
+)
+
 from trinity.utils.queues import (
     queue_get_batch,
     queue_get_nowait,
 )
 
-TFunc = TypeVar('TFunc')
 TPrerequisite = TypeVar('TPrerequisite', bound=Enum)
 TTask = TypeVar('TTask')
 TTaskID = TypeVar('TTaskID')
 
 
-class StaticMethod(Generic[TFunc]):
-    """
-    A property class purely to convince mypy to let us assign a function to an
-    instance variable. See more at: https://github.com/python/mypy/issues/708#issuecomment-405812141
-    """
-    def __get__(self, oself: Any, owner: Any) -> TFunc:
-        return self._func
-
-    def __set__(self, oself: Any, value: TFunc) -> None:
-        self._func = value
-
-
 @total_ordering
 class SortableTask(Generic[TTask]):
     _order_fn: StaticMethod[Callable[[TTask], Any]] = None