initial pass on genesis slot == 0

specs/core/0_beacon-chain.md

@@ -216,8 +216,8 @@ These configurations are updated for releases, but may be out of sync during `de
 | Name | Value |
 | - | - |
 | `GENESIS_FORK_VERSION` | `int_to_bytes4(0)` |
-| `GENESIS_SLOT` | `2**32` |
+| `GENESIS_SLOT` | `0` |
-| `GENESIS_EPOCH` | `slot_to_epoch(GENESIS_SLOT)` |
+| `GENESIS_EPOCH` | `0` |
 | `GENESIS_START_SHARD` | `0` |
 | `FAR_FUTURE_EPOCH` | `2**64 - 1` |
 | `ZERO_HASH` | `int_to_bytes32(0)` |
@@ -1554,7 +1554,7 @@ def get_genesis_beacon_state(genesis_validator_deposits: List[Deposit],
         # Finality
         previous_epoch_attestations=[],
         current_epoch_attestations=[],
-        previous_justified_epoch=GENESIS_EPOCH - 1,
+        previous_justified_epoch=GENESIS_EPOCH,
         current_justified_epoch=GENESIS_EPOCH,
         previous_justified_root=ZERO_HASH,
         current_justified_root=ZERO_HASH,
@@ -1814,6 +1814,9 @@ Run the following function:
 
 ```python
 def update_justification_and_finalization(state: BeaconState) -> None:
+    if get_current_epoch(state) == GENESIS_EPOCH:
+        return
+
     new_justified_epoch = state.current_justified_epoch
     new_finalized_epoch = state.finalized_epoch
 
@@ -1864,7 +1867,7 @@ Run the following function:
 ```python
 def process_crosslinks(state: BeaconState) -> None:
     current_epoch = get_current_epoch(state)
-    previous_epoch = max(current_epoch - 1, GENESIS_EPOCH)
+    previous_epoch = current_epoch if current_epoch == GENESIS_EPOCH else get_previous_epoch(state)
     next_epoch = current_epoch + 1
     for slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(next_epoch)):
         for crosslink_committee, shard in get_crosslink_committees_at_slot(state, slot):
@@ -1999,6 +2002,9 @@ Run the following:
 
 ```python
 def apply_rewards(state: BeaconState) -> None:
+    if get_current_epoch(state) == GENESIS_EPOCH:
+        return
+
     rewards1, penalties1 = get_justification_and_finalization_deltas(state)
     rewards2, penalties2 = get_crosslink_deltas(state)
     for i in range(len(state.validator_registry)):

tests/phase0/block_processing/test_process_attester_slashing.py

@@ -9,6 +9,7 @@ from build.phase0.spec import (
 )
 from tests.phase0.helpers import (
     get_valid_attester_slashing,
+    next_epoch,
 )
 
 # mark entire file as 'attester_slashing'
@@ -59,6 +60,8 @@ def test_success_double(state):
 
 
 def test_success_surround(state):
+    next_epoch(state)
+    state.current_justified_epoch += 1
     attester_slashing = get_valid_attester_slashing(state)
 
     # set attestion1 to surround attestation 2

tests/phase0/helpers.py

@@ -4,6 +4,9 @@ from py_ecc import bls
 
 import build.phase0.spec as spec
 from build.phase0.utils.minimal_ssz import signing_root
+from build.phase0.state_transition import (
+    state_transition,
+)
 from build.phase0.spec import (
     # constants
     EMPTY_SIGNATURE,
@@ -144,7 +147,7 @@ def build_attestation_data(state, slot, shard):
     if epoch_start_slot == slot:
         epoch_boundary_root = block_root
     else:
-        get_block_root(state, epoch_start_slot)
+        epoch_boundary_root = get_block_root(state, epoch_start_slot)
 
     if slot < epoch_start_slot:
         justified_block_root = state.previous_justified_root
@@ -260,7 +263,7 @@ def get_valid_attester_slashing(state):
 def get_valid_attestation(state, slot=None):
     if slot is None:
         slot = state.slot
-    shard = state.latest_start_shard
+    shard = state.latest_start_shard + slot % spec.SLOTS_PER_EPOCH
     attestation_data = build_attestation_data(state, slot, shard)
 
     crosslink_committee = get_crosslink_committee_for_attestation(state, attestation_data)
@@ -312,3 +315,9 @@ def get_attestation_signature(state, attestation_data, privkey, custody_bit=0b0)
             domain_type=spec.DOMAIN_ATTESTATION,
         )
     )
+
+
+def next_epoch(state):
+    block = build_empty_block_for_next_slot(state)
+    block.slot += spec.SLOTS_PER_EPOCH - (state.slot % spec.SLOTS_PER_EPOCH)
+    state_transition(state, block)