Use get_indices_for_slot and get_block_hash

beacon_chain/state/helpers.py

@@ -18,16 +18,18 @@ def get_signed_parent_hashes(active_state,
                              attestation,
                              config=DEFAULT_CONFIG):
     cycle_length = config['cycle_length']
-    oblique_parent_hashes = attestation.oblique_parent_hashes
 
-    parent_hashes = (
-        active_state.recent_block_hashes[
-            cycle_length + attestation.slot - block.slot_number:
-            cycle_length * 2 + attestation.slot - block.slot_number - len(oblique_parent_hashes)
-        ] +
-        oblique_parent_hashes
+    parent_hashes = [
+        get_block_hash(
+            active_state,
+            block,
+            attestation.slot - cycle_length + i,
+            config,
+        )
+        for i
+        in range(cycle_length - len(attestation.oblique_parent_hashes))
+    ] + attestation.oblique_parent_hashes
 
-    )
     return parent_hashes
 
 
@@ -37,19 +39,20 @@ def get_attestation_indices(crystallized_state,
     last_state_recalc = crystallized_state.last_state_recalc
     cycle_length = config['cycle_length']
     indices_for_slots = crystallized_state.indices_for_slots
-
-    shard_position = list(filter(
-        lambda x: (
-            indices_for_slots[attestation.slot - last_state_recalc + cycle_length][x].shard_id ==
-            attestation.shard_id
-        ),
-        range(len(indices_for_slots[attestation.slot - last_state_recalc + cycle_length]))
-    ))[0]
-    attestation_indices = (
-        indices_for_slots[
-            attestation.slot - last_state_recalc + cycle_length
-        ][shard_position].committee
+    shard_id = attestation.shard_id
+
+    filtered_indices_for_slot = list(
+        filter(
+            lambda x: x.shard_id == shard_id,
+            get_indices_for_slot(
+                crystallized_state,
+                attestation.slot,
+                config=config,
+            )
+        )
     )
+    if filtered_indices_for_slot:
+        attestation_indices = filtered_indices_for_slot[0].committee
 
     return attestation_indices
 

tests/state/helpers.py

@@ -1,6 +1,7 @@
 from beacon_chain.state.config import (
     DEFAULT_CONFIG,
 )
+from beacon_chain.state.block import Block
 from beacon_chain.state.validator_record import (
     ValidatorRecord,
 )
@@ -16,3 +17,18 @@ def mock_validator_record(pubkey, start_dynasty=0, config=DEFAULT_CONFIG):
         start_dynasty=start_dynasty,
         end_dynasty=config['default_end_dynasty']
     )
+
+
+def get_pseudo_chain(length):
+    """Get a pseudo chain, only slot_number and parent_hash are valid.
+    """
+    blocks = []
+    for slot in range(length * 3):
+        blocks.append(
+            Block(
+                slot_number=slot,
+                parent_hash=blocks[slot-1].hash if slot > 0 else b'00'*32
+            )
+        )
+
+    return blocks

tests/state/test_helpers.py

@@ -10,6 +10,10 @@
     get_block_hash,
 )
 
+from tests.state.helpers import(
+    get_pseudo_chain,
+)
+
 
 @pytest.mark.parametrize(
     (
@@ -34,12 +38,6 @@ def test_get_new_shuffling_is_complete(genesis_validators, config):
     )
 
     assert len(shuffling) == config['cycle_length']
-    print([
-        [j.committee 
-        for j in item]
-        for item in shuffling]
-    )
-    print('shuffling: {}'.format(shuffling))
     validators = set()
     shards = set()
     for height_indices in shuffling:
@@ -103,7 +101,7 @@ def test_get_block_hash(
         config):
     cycle_length = config['cycle_length']
 
-    blocks = get_empty_chain(cycle_length * 3)
+    blocks = get_pseudo_chain(cycle_length * 3)
     active_state = ActiveState(
         recent_block_hashes=[block.hash for block in blocks[:cycle_length*2]]
     )
@@ -123,16 +121,3 @@ def test_get_block_hash(
                 slot,
                 config=config,
             )
-
-
-def get_empty_chain(length):
-    blocks = []
-    for slot in range(length * 3):
-        blocks.append(
-            Block(
-                slot_number=slot,
-                parent_hash=blocks[slot-1].hash if slot > 0 else b'00'*32
-            )
-        )
-
-    return blocks