Explicit uint vs int support *everywhere*

beacon_chain/state/attestation_record.py

@@ -10,14 +10,14 @@
 
 class AttestationRecord():
     fields = {
-        'slot': 'int64',
-        'shard_id': 'int16',
+        'slot': 'uint64',
+        'shard_id': 'uint16',
         'oblique_parent_hashes': ['hash32'],
         'shard_block_hash': 'hash32',
         'attester_bitfield': 'bytes',
-        'justified_slot': 'int64',
+        'justified_slot': 'uint64',
         'justified_block_hash': 'hash32',
-        'aggregate_sig': ['int256'],
+        'aggregate_sig': ['uint256'],
     }
     defaults = {
         'slot': 0,

beacon_chain/state/block.py

@@ -20,7 +20,7 @@ class Block():
         # Hash of the parent block
         'parent_hash': 'hash32',
         # Slot number (for the PoS mechanism)
-        'slot_number': 'int64',
+        'slot_number': 'uint64',
         # Randao commitment reveal
         'randao_reveal': 'hash32',
         # Attestations

beacon_chain/state/crosslink_record.py

@@ -7,9 +7,9 @@
 class CrosslinkRecord():
     fields = {
         # What dynasty the crosslink was submitted in
-        'dynasty': 'int64',
+        'dynasty': 'uint64',
         # slot during which crosslink was added
-        'slot': 'int64',
+        'slot': 'uint64',
         # The block hash
         'hash': 'hash32',
     }

beacon_chain/state/crystallized_state.py

@@ -16,25 +16,25 @@ class CrystallizedState():
         # List of validators
         'validators': [ValidatorRecord],
         # Last CrystallizedState recalculation
-        'last_state_recalc': 'int64',
+        'last_state_recalc': 'uint64',
         # What active validators are part of the attester set
         # at what height, and in what shard. Starts at slot
         # last_state_recalc - CYCLE_LENGTH
         'shard_and_committee_for_slots': [[ShardAndCommittee]],
         # The last justified slot
-        'last_justified_slot': 'int64',
+        'last_justified_slot': 'uint64',
         # Number of consecutive justified slots ending at this one
-        'justified_streak': 'int64',
+        'justified_streak': 'uint64',
         # The last finalized slot
-        'last_finalized_slot': 'int64',
+        'last_finalized_slot': 'uint64',
         # The current dynasty
-        'current_dynasty': 'int64',
+        'current_dynasty': 'uint64',
         # Records about the most recent crosslink for each shard
         'crosslink_records': [CrosslinkRecord],
         # Used to select the committees for each shard
         'dynasty_seed': 'hash32',
         # start of the current dynasty
-        'dynasty_start': 'int64',
+        'dynasty_start': 'uint64',
     }
     defaults = {
         'validators': [],

beacon_chain/state/shard_and_committee.py

@@ -7,9 +7,9 @@
 class ShardAndCommittee():
     fields = {
         # The shard ID
-        'shard_id': 'int16',
+        'shard_id': 'uint16',
         # Validator indices
-        'committee': ['int24'],
+        'committee': ['uint24'],
     }
 
     defaults = {

beacon_chain/state/validator_record.py

@@ -7,19 +7,19 @@
 class ValidatorRecord():
     fields = {
         # The validator's public key
-        'pubkey': 'int256',
+        'pubkey': 'uint256',
         # What shard the validator's balance will be sent to after withdrawal
-        'withdrawal_shard': 'int16',
+        'withdrawal_shard': 'uint16',
         # And what address
         'withdrawal_address': 'address',
         # The validator's current RANDAO beacon commitment
         'randao_commitment': 'hash32',
         # Current balance
-        'balance': 'int128',
+        'balance': 'uint128',
         # Dynasty where the validator is inducted
-        'start_dynasty': 'int64',
+        'start_dynasty': 'uint64',
         # Dynasty where the validator leaves
-        'end_dynasty': 'int64'
+        'end_dynasty': 'uint64'
     }
 
     defaults = {

ssz/ssz.py

@@ -9,7 +9,12 @@ def serialize(val, typ=None):
         return val
     elif isinstance(typ, str) and typ[:3] == 'int':
         length = int(typ[3:])
+        assert length % 8 == 0 
+        return val.to_bytes(length // 8, 'big', signed=True)
+    elif isinstance(typ, str) and typ[:4] == 'uint':
+        length = int(typ[4:])
         assert length % 8 == 0
+        assert val >= 0
         return val.to_bytes(length // 8, 'big')
     elif typ == 'bytes':
         return len(val).to_bytes(4, 'big') + val
@@ -34,6 +39,11 @@ def _deserialize(data, start, typ):
         length = int(typ[3:])
         assert length % 8 == 0
         assert len(data) + start >= length // 8
+        return int.from_bytes(data[start: start+length//8], 'big', signed=True), start+length//8
+    elif isinstance(typ, str) and typ[:4] == 'uint':
+        length = int(typ[4:])
+        assert length % 8 == 0
+        assert len(data) + start >= length // 8
         return int.from_bytes(data[start: start+length//8], 'big'), start+length//8
     elif typ == 'bytes':
         length = int.from_bytes(data[start:start+4], 'big')

tests/ssz/test_serialize.py

@@ -30,7 +30,7 @@ def test_basic_serialization(value, typ, data):
         (b'', 'byte'),
         (b'', 'hash16'),
         (0, 0),
-        (-5, 'int32'),
+        (-5, 'uint32'),
     ]
 )
 def test_failed_serialization(value, typ):