Chain builder tool (#1209)

* start building chain builder

* move docs to docstrings

* PR feedback

* pr feedback

* fix doctests

* fix chain_split and docs

Author: pipermerriam

docs/api/eth/api.tools.rst

@@ -7,4 +7,5 @@ Tools
    :name: toc-eth-api-tools
    :caption: Tools
 
+   tools/api.tools.builders
    tools/api.tools.fixtures

docs/api/eth/tools/api.tools.builders.rst

@@ -0,0 +1,72 @@
+Builders
+========
+
+
+Chain Builder
+-------------
+
+The chain builder utils are intended to reduce common boilerplace for both
+construction of chain classes as well as building up some desired chain state.
+
+.. note:: These tools are best used in conjunction with ``cytoolz.pipe``.
+
+
+Constructing Chain Classes
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The following utilities are provided to assist with constructing a chain class.
+
+
+.. autofunction:: eth.tools.builder.chain.fork_at
+
+
+.. autofunction:: eth.tools.builder.chain.dao_fork_at
+
+
+.. autofunction:: eth.tools.builder.chain.disable_dao_fork
+
+
+.. autofunction:: eth.tools.builder.chain.enable_pow_mining
+
+
+.. autofunction:: eth.tools.builder.chain.disable_pow_check
+
+
+.. autofunction:: eth.tools.builder.chain.name
+
+
+Initializing Chains
+~~~~~~~~~~~~~~~~~~~
+
+The following utilities are provided to assist with initializing a chain into
+the genesis state.
+
+.. autofunction:: eth.tools.builder.chain.genesis
+
+
+Building Chains
+~~~~~~~~~~~~~~~
+
+The following utilities are provided to assist with building out chains of
+blocks.
+
+
+.. autofunction:: eth.tools.builder.chain.copy
+
+
+.. autofunction:: eth.tools.builder.chain.import_block
+
+
+.. autofunction:: eth.tools.builder.chain.import_blocks
+
+
+.. autofunction:: eth.tools.builder.chain.mine_block
+
+
+.. autofunction:: eth.tools.builder.chain.mine_blocks
+
+
+.. autofunction:: eth.tools.builder.chain.chain_split
+
+
+.. autofunction:: eth.tools.builder.chain.at_block_number

docs/api/eth/tools/api.tools.fixtures.rst

@@ -155,8 +155,9 @@ sequence of functions.
     support only a single expectation with no specified network and no transaction (here, its role is
     played by :func:`~eth.tools.fixtures.fillers.execution`).
 
-    * ``post_state`` is a list of state definition in the same form as expected by `pre_state`. State items
-      that are not set explicitly default to their pre state.
+    * ``post_state`` is a list of state definition in the same form as expected
+      by :func:`~eth.tools.fixtures.fillers.pre_state`. State items that are
+      not set explicitly default to their pre state.
 
     * ``networks`` defines the forks under which the expectation is applicable. It should be a sublist of
       the following identifiers (also available in `ALL_FORKS`):

eth/chains/base.py

@@ -849,7 +849,7 @@ def mine_block(self, *args: Any, **kwargs: Any) -> BaseBlock:
         self.validate_block(mined_block)
 
         self.chaindb.persist_block(mined_block)
-        self.header = self.ensure_header()
+        self.header = self.create_header_from_parent(mined_block.header)
         return mined_block
 
     def get_vm(self, at_header: BlockHeader=None) -> 'BaseVM':

eth/chains/mainnet/__init__.py

@@ -62,14 +62,22 @@ class MainnetHomesteadVM(MainnetDAOValidatorVM, HomesteadVM):
     pass
 
 
-MAINNET_VM_CONFIGURATION = (
-    (0, FrontierVM),
-    (HOMESTEAD_MAINNET_BLOCK, MainnetHomesteadVM),
-    (TANGERINE_WHISTLE_MAINNET_BLOCK, TangerineWhistleVM),
-    (SPURIOUS_DRAGON_MAINNET_BLOCK, SpuriousDragonVM),
-    (BYZANTIUM_MAINNET_BLOCK, ByzantiumVM),
+MAINNET_FORK_BLOCKS = (
+    0,
+    HOMESTEAD_MAINNET_BLOCK,
+    TANGERINE_WHISTLE_MAINNET_BLOCK,
+    SPURIOUS_DRAGON_MAINNET_BLOCK,
+    BYZANTIUM_MAINNET_BLOCK,
+)
+MAINNET_VMS = (
+    FrontierVM,
+    MainnetHomesteadVM,
+    TangerineWhistleVM,
+    SpuriousDragonVM,
+    ByzantiumVM,
 )
 
+MAINNET_VM_CONFIGURATION = tuple(zip(MAINNET_FORK_BLOCKS, MAINNET_VMS))
 
 MAINNET_NETWORK_ID = 1
 

eth/tools/builder/__init__.py

@@ -0,0 +1,89 @@
+from .builders import (  # noqa: F401
+    at_block_number,
+    build,
+    chain_split,
+    copy,
+    dao_fork_at,
+    disable_dao_fork,
+    disable_pow_check,
+    enable_pow_mining,
+    fork_at,
+    genesis,
+    import_block,
+    import_blocks,
+    mine_block,
+    mine_blocks,
+    name,
+)
+from .builders import (  # noqa: F401
+    byzantium_at,
+    frontier_at,
+    homestead_at,
+    spurious_dragon_at,
+    tangerine_whistle_at,
+    constantinople_at,
+)
+
+
+mainnet_fork_at_fns = (
+    byzantium_at,
+    frontier_at,
+    homestead_at,
+    spurious_dragon_at,
+    tangerine_whistle_at,
+    constantinople_at,
+)
+
+
+class API:
+    #
+    # Chain Class Construction
+    #
+
+    # Primary wrapper function
+    build = staticmethod(build)
+
+    # Configure chain vm_configuration
+    fork_at = staticmethod(fork_at)
+
+    # Mainnet Forks
+    frontier_at = staticmethod(frontier_at)
+    homestead_at = staticmethod(homestead_at)
+    tangerine_whistle_at = staticmethod(tangerine_whistle_at)
+    spurious_dragon_at = staticmethod(spurious_dragon_at)
+    byzantium_at = staticmethod(byzantium_at)
+    constantinople_at = staticmethod(constantinople_at)
+
+    # iterable of the fork specific functions
+    mainnet_fork_at_fns = staticmethod(mainnet_fork_at_fns)
+
+    # DAO Fork specific
+    dao_fork_at = staticmethod(dao_fork_at)
+    disable_dao_fork = staticmethod(disable_dao_fork)
+
+    # Chain Mining config
+    enable_pow_mining = staticmethod(enable_pow_mining)
+    disable_pow_check = staticmethod(disable_pow_check)
+
+    #
+    # Chain Instance Initialization
+    #
+    name = staticmethod(name)
+    genesis = staticmethod(genesis)
+
+    #
+    # Chain Building
+    #
+    copy = staticmethod(copy)
+
+    import_block = staticmethod(import_block)
+    import_blocks = staticmethod(import_blocks)
+
+    mine_block = staticmethod(mine_block)
+    mine_blocks = staticmethod(mine_blocks)
+
+    chain_split = staticmethod(chain_split)
+    at_block_number = staticmethod(at_block_number)
+
+
+api = API()