Merge is_genesis_trigger into get_genesis_state

specs/core/0_beacon-chain.md

@@ -94,7 +94,6 @@
             - [`initiate_validator_exit`](#initiate_validator_exit)
             - [`slash_validator`](#slash_validator)
     - [Genesis](#genesis)
-        - [Genesis trigger](#genesis-trigger)
         - [Genesis state](#genesis-state)
         - [Genesis block](#genesis-block)
     - [Beacon chain state transition function](#beacon-chain-state-transition-function)
@@ -190,7 +189,7 @@ The following values are (non-configurable) constants used throughout the specif
 | `MIN_PER_EPOCH_CHURN_LIMIT` | `2**2` (= 4) |
 | `CHURN_LIMIT_QUOTIENT` | `2**16` (= 65,536) |
 | `SHUFFLE_ROUND_COUNT` | `90` |
-| `GENESIS_ACTIVE_VALIDATOR_COUNT` | `2**16` (= 65,536) |
+| `MIN_GENESIS_ACTIVE_VALIDATOR_COUNT` | `2**16` (= 65,536) |
 | `MIN_GENESIS_TIME` | `1578009600` (Jan 3, 2020) |
 | `JUSTIFICATION_BITS_LENGTH` | `4` |
 
@@ -1091,35 +1090,28 @@ def slash_validator(state: BeaconState,
 
 ## Genesis
 
-### Genesis trigger
+### Genesis state
 
-Before genesis has been triggered and for every Ethereum 1.0 block call `is_genesis_trigger(deposits: Sequence[Deposit], timestamp: uint64) -> bool` where:
+Before the Ethereum 2.0 genesis has been triggered and for every Ethereum 1.0 block, call `get_genesis_beacon_state(eth1_block_hash, eth1_timestamp, deposits)` where:
 
-* `deposits` is the sequence of all deposits, ordered chronologically, up to and including the deposit triggering the latest `Deposit` log
+* `eth1_block_hash` is the hash of the Ethereum 1.0 block
-* `timestamp` is the Unix timestamp in the Ethereum 1.0 block that emitted the latest `Deposit` log
+* `eth1_timestamp` is the Unix timestamp corresponding to `eth1_block_hash`
+* `deposits` is the sequence of all deposits, ordered chronologically, up to the block with hash `eth1_block_hash`
 
-When `is_genesis_trigger(deposits, timestamp) is True` for the first time, let:
+The genesis state `genesis_state` is defined as the return value of the first call to `get_genesis_beacon_state` that does not trigger an `assert`.
 
-* `genesis_deposits = deposits`
+*Note*: The two constants `MIN_GENESIS_TIME` and `MIN_GENESIS_ACTIVE_VALIDATOR_COUNT` in `get_genesis_beacon_state` have yet to be agreed upon by the community, and can be updated as necessary.
-* `genesis_time = timestamp - timestamp % SECONDS_PER_DAY + 2 * SECONDS_PER_DAY`
-* `genesis_eth1_block_hash` is the Ethereum 1.0 block hash that emitted the log for the last deposit in `deposits`
-
-*Note*: The function `is_genesis_trigger` has yet to be agreed upon by the community, and can be updated as necessary. We define the following testing placeholder:
 
 ```python
-def is_genesis_trigger(deposits: Sequence[Deposit], timestamp: uint64) -> bool:
+def get_genesis_beacon_state(eth1_block_hash: Hash, eth1_timestamp: int, deposits: Sequence[Deposit]) -> BeaconState:
-    # Do not deploy too early
+    state = BeaconState(
-    if timestamp - timestamp % SECONDS_PER_DAY + 2 * SECONDS_PER_DAY < MIN_GENESIS_TIME:
+        genesis_time=timestamp - timestamp % SECONDS_PER_DAY + 2 * SECONDS_PER_DAY,
-        return False
+        eth1_data=Eth1Data(block_hash=genesis_eth1_block_hash),
-    # Process genesis deposits
+        latest_block_header=BeaconBlockHeader(body_root=hash_tree_root(BeaconBlockBody())),
-    state = BeaconState()
+    )
-    process_genesis_deposits(state, deposits)
+    assert state.genesis_time >= MIN_GENESIS_TIME
-    # Check active validator count
-    return len(get_active_validator_indices(state, GENESIS_EPOCH)) >= GENESIS_ACTIVE_VALIDATOR_COUNT
-```
 
-```python
+    # Process deposits
-def process_genesis_deposits(state: BeaconState, deposits: Sequence[Deposit]) -> None:
     leaves = list(map(lambda deposit: deposit.data, deposits))
     for deposit_index, deposit in enumerate(deposits):
         state.eth1_data.deposit_root = hash_tree_root(
@@ -1133,23 +1125,7 @@ def process_genesis_deposits(state: BeaconState, deposits: Sequence[Deposit]) ->
         if validator.effective_balance == MAX_EFFECTIVE_BALANCE:
             validator.activation_eligibility_epoch = GENESIS_EPOCH
             validator.activation_epoch = GENESIS_EPOCH
-```
+    assert len(get_active_validator_indices(state, GENESIS_EPOCH)) >= MIN_GENESIS_ACTIVE_VALIDATOR_COUNT
-
-### Genesis state
-
-Let `genesis_state = get_genesis_beacon_state(genesis_deposits, genesis_time, genesis_eth1_block_hash)`.
-
-```python
-def get_genesis_beacon_state(deposits: Sequence[Deposit],
-                             genesis_time: int,
-                             genesis_eth1_block_hash: Hash) -> BeaconState:
-    # Process genesis deposits
-    state = BeaconState(
-        genesis_time=genesis_time,
-        eth1_data=Eth1Data(block_hash=genesis_eth1_block_hash),
-        latest_block_header=BeaconBlockHeader(body_root=hash_tree_root(BeaconBlockBody())),
-    )
-    process_genesis_deposits(state, deposits)
 
     # Populate active_index_roots
     genesis_active_index_root = hash_tree_root(