Add total_validator_count field to ShardCommittee

Author: hwwhww

eth/beacon/helpers.py

@@ -232,14 +232,16 @@ def get_active_validator_indices(validators: Sequence['ValidatorRecord']) -> Tup
 def _get_shards_and_committees_for_shard_indices(
         shard_indices: Sequence[Sequence[int]],
         start_shard: int,
+        total_validator_count: int,
         shard_count: int) -> Iterable[ShardCommittee]:
     """
     Returns filled [ShardCommittee] tuple.
     """
     for index, indices in enumerate(shard_indices):
         yield ShardCommittee(
             shard=(start_shard + index) % shard_count,
-            committee=indices
+            committee=indices,
+            total_validator_count=total_validator_count,
         )
 
 
@@ -312,6 +314,7 @@ def get_new_shuffling(*,
         yield _get_shards_and_committees_for_shard_indices(
             shard_indices,
             start_shard,
+            active_validators_size,
             shard_count,
         )
 

eth/beacon/types/shard_committees.py

@@ -22,15 +22,17 @@ class ShardCommittee(rlp.Serializable):
         ('shard', uint64),
         # Validator indices
         ('committee', CountableList(uint24)),
+        # Total validator count (for proofs of custody)
+        ('total_validator_count', uint64),
     ]
 
     def __init__(self,
                  shard: int,
-                 committee: Sequence[int])-> None:
-        if committee is None:
-            committee = ()
+                 committee: Sequence[int],
+                 total_validator_count: int)-> None:
 
         super().__init__(
             shard=shard,
             committee=committee,
+            total_validator_count=total_validator_count,
         )

tests/beacon/conftest.py

@@ -188,6 +188,7 @@ def sample_shard_committee_params():
     return {
         'shard': 10,
         'committee': (1, 3, 5),
+        'total_validator_count': 100
     }
 
 

tests/beacon/types/test_shard_committee.py

@@ -7,3 +7,4 @@ def test_defaults(sample_shard_committee_params):
     shard_committee = ShardCommittee(**sample_shard_committee_params)
     assert shard_committee.shard == sample_shard_committee_params['shard']
     assert shard_committee.committee == sample_shard_committee_params['committee']
+    assert shard_committee.total_validator_count == sample_shard_committee_params['total_validator_count']