Move mainnet DAO fork config into mainnet configuration (#1433)

* Move mainnet DAO fork config into mainnet configuration

* make explicit configuration of dao fork required

* make dao_fork_block_number property private

Author: pipermerriam

eth/chains/mainnet/__init__.py

@@ -13,6 +13,7 @@
     HOMESTEAD_MAINNET_BLOCK,
     SPURIOUS_DRAGON_MAINNET_BLOCK,
     DAO_FORK_MAINNET_EXTRA_DATA,
+    DAO_FORK_MAINNET_BLOCK,
 )
 from eth import constants as eth_constants
 
@@ -39,7 +40,8 @@ def validate_header(cls, header, previous_header, check_seal=True):
         super().validate_header(header, previous_header, check_seal)  # type: ignore
 
         # The special extra_data is set on the ten headers starting at the fork
-        extra_data_block_nums = range(cls.dao_fork_block_number, cls.dao_fork_block_number + 10)
+        dao_fork_at = cls.get_dao_fork_block_number()
+        extra_data_block_nums = range(dao_fork_at, dao_fork_at + 10)
 
         if header.block_number in extra_data_block_nums:
             if cls.support_dao_fork and header.extra_data != DAO_FORK_MAINNET_EXTRA_DATA:
@@ -60,7 +62,7 @@ def validate_header(cls, header, previous_header, check_seal=True):
 
 
 class MainnetHomesteadVM(MainnetDAOValidatorVM, HomesteadVM):
-    pass
+    _dao_fork_block_number = DAO_FORK_MAINNET_BLOCK
 
 
 MAINNET_FORK_BLOCKS = (

eth/chains/mainnet/constants.py

@@ -1,3 +1,6 @@
+from eth_typing import BlockNumber
+
+
 # https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md
 MAINNET_CHAIN_ID = 1
 
@@ -13,7 +16,7 @@
 #
 # DAO Block
 #
-DAO_FORK_MAINNET_BLOCK = 1920000
+DAO_FORK_MAINNET_BLOCK = BlockNumber(1920000)
 
 DAO_FORK_MAINNET_EXTRA_DATA = b'dao-hard-fork'
 

eth/chains/tester/__init__.py

@@ -120,10 +120,10 @@ def _generate_vm_configuration(*fork_start_blocks: ForkStartBlocks,
             if dao_start_block is False:
                 yield (start_block, vm_class.configure(support_dao_fork=False))
             elif dao_start_block is None:
-                yield (start_block, vm_class.configure(dao_fork_block_number=start_block))
+                yield (start_block, vm_class.configure(_dao_fork_block_number=start_block))
             elif isinstance(dao_start_block, int):
                 validate_gte(dao_start_block, start_block)
-                yield (start_block, vm_class.configure(dao_fork_block_number=dao_start_block))
+                yield (start_block, vm_class.configure(_dao_fork_block_number=dao_start_block))
             else:
                 raise Exception("Invariant: unreachable code path")
         else:

eth/tools/builder/chain/builders.py

@@ -186,20 +186,20 @@ def disable_dao_fork(chain_class: BaseChain) -> type:
 
 
 @to_tuple
-def _set_vm_dao_fork_block_number(dao_fork_block_number: int,
+def _set_vm_dao_fork_block_number(dao_fork_block_number: BlockNumber,
                                   vm_configuration: VMConfiguration) -> VMConfiguration:
     for fork_block, vm_class in vm_configuration:
         if _is_homestead(vm_class):
             yield fork_block, vm_class.configure(
                 support_dao_fork=True,
-                dao_fork_block_number=dao_fork_block_number,
+                _dao_fork_block_number=dao_fork_block_number,
             )
         else:
             yield fork_block, vm_class
 
 
 @curry
-def dao_fork_at(dao_fork_block_number: int, chain_class: BaseChain) -> type:
+def dao_fork_at(dao_fork_block_number: BlockNumber, chain_class: BaseChain) -> type:
     """
     Set the block number on which the DAO fork will happen.  Requires that a
     version of the :class:`~eth.vm.forks.homestead.HomesteadVM` is present in

eth/tools/fixtures/helpers.py

@@ -115,7 +115,7 @@ def chain_vm_configuration(fixture):
     elif network == 'HomesteadToDaoAt5':
         HomesteadVM = BaseHomesteadVM.configure(
             support_dao_fork=True,
-            dao_fork_block_number=5,
+            _dao_fork_block_number=5,
         )
         return (
             (0, HomesteadVM),

eth/vm/forks/homestead/__init__.py

@@ -1,10 +1,9 @@
-from typing import Type  # noqa: F401
+from typing import Optional, Type  # noqa: F401
 from eth.rlp.blocks import BaseBlock  # noqa: F401
 from eth.vm.state import BaseState  # noqa: F401
 
-from eth.chains.mainnet.constants import (
-    DAO_FORK_MAINNET_BLOCK
-)
+from eth_typing import BlockNumber
+
 from eth.vm.forks.frontier import FrontierVM
 
 from .blocks import HomesteadBlock
@@ -18,7 +17,13 @@
 
 class MetaHomesteadVM(FrontierVM):
     support_dao_fork = True
-    dao_fork_block_number = DAO_FORK_MAINNET_BLOCK
+    _dao_fork_block_number = None  # type: Optional[BlockNumber]
+
+    @classmethod
+    def get_dao_fork_block_number(cls) -> BlockNumber:
+        if cls._dao_fork_block_number is None:
+            raise TypeError("HomesteadVM must be configured with a valid `_dao_fork_block_number`")
+        return cls._dao_fork_block_number
 
 
 class HomesteadVM(MetaHomesteadVM):

eth/vm/forks/homestead/headers.py

@@ -75,7 +75,7 @@ def configure_homestead_header(vm, **header_params):
         # get to that. Another alternative would be to do it in Block.mine(), but
         # there we'd need to manually instantiate the State and update
         # header.state_root after we're done.
-        if vm.support_dao_fork and changeset.block_number == vm.dao_fork_block_number:
+        if vm.support_dao_fork and changeset.block_number == vm.get_dao_fork_block_number():
             state = vm.state
 
             for account in dao_drain_list:

tests/core/chain-object/test_chain_reorganization.py

@@ -7,9 +7,14 @@
 
 @pytest.fixture(params=api.mainnet_fork_at_fns)
 def base_chain(request):
+    if request.param is api.homestead_at:
+        fork_fns = (request.param(0), api.dao_fork_at(0))
+    else:
+        fork_fns = (request.param(0),)
+
     chain = api.build(
         MiningChain,
-        request.param(0),
+        *fork_fns,
         api.disable_pow_check(),
         api.genesis(),
     )

tests/core/tester/test_generate_vm_configuration.py

@@ -129,10 +129,10 @@ def test_generate_vm_configuration(args, kwargs, expected):
                 assert left_vm.support_dao_fork is False
             elif dao_start_block is None:
                 assert left_vm.support_dao_fork is True
-                assert left_vm.dao_fork_block_number == right_block
+                assert left_vm.get_dao_fork_block_number() == right_block
             else:
                 assert left_vm.support_dao_fork is True
-                assert left_vm.dao_fork_block_number == dao_start_block
+                assert left_vm.get_dao_fork_block_number() == dao_start_block
         elif right_vm == Forks.TangerineWhistle:
             assert 'TangerineWhistle' in left_vm.__name__
         elif right_vm == Forks.SpuriousDragon:

tests/trinity/json-fixtures-over-rpc/test_rpc_fixtures.py

@@ -389,7 +389,7 @@ async def test_rpc_against_fixtures(chain, ipc_server, chain_fixture, fixture_da
     rpc = RPCServer(MainnetFullChain(None))
 
     setup_result, setup_error = await call_rpc(rpc, 'evm_resetToGenesisFixture', [chain_fixture])
-    assert setup_error is None and setup_result is True, "cannot load chain for %r" % fixture_data
+    assert setup_error is None and setup_result is True, "cannot load chain for {0}".format(fixture_data)  # noqa: E501
 
     await validate_accounts(rpc, chain_fixture['pre'])