refactor(forks): move verify_signatures body into the spec (Stage 4C, part 1 of #686)

packages/testing/src/consensus_testing/genesis.py

@@ -4,18 +4,12 @@
 from lean_spec.forks.lstar.containers.state import State, Validators
 from lean_spec.forks.lstar.containers.validator import Validator
 from lean_spec.forks.lstar.spec import LstarSpec
-from lean_spec.forks.protocol import ForkProtocol
 from lean_spec.subspecs.ssz.hash import hash_tree_root
 from lean_spec.types import Bytes52, Slot, Uint64, ValidatorIndex
 
 from .keys import XmssKeyManager
 
 _DEFAULT_GENESIS_TIME = Uint64(0)
-_SPEC = LstarSpec()
-"""Active fork spec — stateless, safe to share across all helper invocations."""
-
-_DEFAULT_FORK: ForkProtocol = _SPEC
-"""Stateless fork instance used when callers do not pass one explicitly."""
 
 
 def _build_validators(num_validators: int) -> Validators:
@@ -44,30 +38,30 @@ def _build_validators(num_validators: int) -> Validators:
 
 
 def generate_pre_state(
-    fork: ForkProtocol = _DEFAULT_FORK,
+    fork: LstarSpec | None = None,
     genesis_time: Uint64 = _DEFAULT_GENESIS_TIME,
     num_validators: int = 4,
 ) -> State:
     """Generate a default pre-state for consensus tests.
 
     Args:
-        fork: Fork dispatching genesis construction.
+        fork: Fork dispatching genesis construction. Defaults to a fresh
+            LstarSpec instance.
         genesis_time: The genesis timestamp.
         num_validators: Number of validators to include.
 
     Returns:
         A properly initialized consensus state.
     """
+    fork = fork or LstarSpec()
     validators = _build_validators(num_validators)
-    state = fork.generate_genesis(genesis_time=genesis_time, validators=validators)
-    assert isinstance(state, State)
-    return state
+    return fork.generate_genesis(genesis_time=genesis_time, validators=validators)
 
 
 def build_anchor(
     num_validators: int,
     anchor_slot: Slot,
-    fork: ForkProtocol = _DEFAULT_FORK,
+    fork: LstarSpec | None = None,
     genesis_time: Uint64 = _DEFAULT_GENESIS_TIME,
 ) -> tuple[State, Block]:
     """Build a consistent non-genesis anchor by advancing the genesis state.
@@ -101,6 +95,7 @@ def build_anchor(
             "For a genesis anchor use generate_pre_state instead."
         )
 
+    fork = fork or LstarSpec()
     state = generate_pre_state(fork=fork, genesis_time=genesis_time, num_validators=num_validators)
 
     # Reconstruct the genesis block from the state's latest header.
@@ -124,7 +119,7 @@ def build_anchor(
     for next_slot in range(1, int(anchor_slot) + 1):
         slot = Slot(next_slot)
         proposer_index = ValidatorIndex(int(slot) % int(num_validators_u64))
-        current_block, state, _, _ = _SPEC.build_block(
+        current_block, state, _, _ = fork.build_block(
             state,
             slot=slot,
             proposer_index=proposer_index,

packages/testing/src/consensus_testing/test_fixtures/api_endpoint.py

@@ -53,7 +53,7 @@ def _build_store(num_validators: int, genesis_time: int, anchor_slot: int = 0) -
         )
         block = _make_genesis_block(state)
         # No validator identity — fixture only reads store data, never signs.
-        return Store.from_anchor(state, block, validator_id=None)
+        return fork.create_store(state, block, validator_id=None)
 
     # Walk the chain from genesis through anchor_slot using empty blocks.
     # The returned pair (state, block) is internally consistent with the
@@ -64,7 +64,7 @@ def _build_store(num_validators: int, genesis_time: int, anchor_slot: int = 0) -
         anchor_slot=Slot(anchor_slot),
         genesis_time=Uint64(genesis_time),
     )
-    return Store.from_anchor(state, block, validator_id=None)
+    return fork.create_store(state, block, validator_id=None)
 
 
 def _health_response(_store: Store, _fixture: "ApiEndpointTest") -> dict[str, Any]:
@@ -100,7 +100,7 @@ def _finalized_state_response(store: Store, _fixture: "ApiEndpointTest") -> dict
 
 def _fork_choice_response(store: Store, _fixture: "ApiEndpointTest") -> dict[str, Any]:
     """Fork choice tree: blocks with weights, head, checkpoints, validator count."""
-    weights = store.compute_block_weights()
+    weights = LstarSpec().compute_block_weights(store)
 
     # Only post-finalization blocks are relevant to head selection.
     nodes = [

packages/testing/src/consensus_testing/test_fixtures/fork_choice.py

@@ -11,7 +11,6 @@
 
 from pydantic import Field, model_validator
 
-from lean_spec.forks.lstar import Store
 from lean_spec.forks.lstar.containers.block import (
     Block,
     BlockBody,
@@ -38,9 +37,6 @@
 )
 from .base import BaseConsensusFixture
 
-_SPEC = LstarSpec()
-"""Active fork spec — stateless, safe to share across all fixture invocations."""
-
 
 class ForkChoiceTest(BaseConsensusFixture):
     """
@@ -190,6 +186,8 @@ def make_fixture(self) -> Self:
         assert self.anchor_block is not None, "anchor block must be set before making fixture"
         assert self.max_slot is not None, "max slot must be set before making fixture"
 
+        spec = LstarSpec()
+
         # Expected anchor-init failure path.
         #
         # When anchor_valid is False, the test asserts that Store.from_anchor
@@ -202,7 +200,7 @@ def make_fixture(self) -> Self:
                 "Store.from_anchor is expected to fail before any step can run"
             )
             try:
-                Store.from_anchor(
+                spec.create_store(
                     self.anchor_state,
                     self.anchor_block,
                     validator_id=ValidatorIndex(0),
@@ -257,7 +255,7 @@ def make_fixture(self) -> Self:
         #
         # The Store is the node's local view of the chain.
         # It starts from a trusted anchor (usually genesis).
-        store = Store.from_anchor(
+        store = spec.create_store(
             self.anchor_state,
             self.anchor_block,
             validator_id=ValidatorIndex(0),
@@ -293,7 +291,7 @@ def make_fixture(self) -> Self:
                             target_interval = Interval.from_unix_time(
                                 Uint64(step.time), store.config.genesis_time
                             )
-                        store, _ = _SPEC.on_tick(
+                        store, _ = spec.on_tick(
                             store,
                             target_interval,
                             has_proposal=step.has_proposal,
@@ -326,13 +324,13 @@ def make_fixture(self) -> Self:
                         # This tick includes a block (has proposal).
                         # Always act as aggregator to ensure gossip signatures are aggregated
                         target_interval = Interval.from_slot(block.slot)
-                        store, _ = _SPEC.on_tick(
+                        store, _ = spec.on_tick(
                             store, target_interval, has_proposal=True, is_aggregator=True
                         )
 
                         # Process the block through Store.
                         # This validates, applies state transition, and updates the store's head.
-                        store = _SPEC.on_block(
+                        store = spec.on_block(
                             store,
                             signed_block,
                             scheme=LEAN_ENV_TO_SCHEMES[self.lean_env],
@@ -350,7 +348,7 @@ def make_fixture(self) -> Self:
                             step.valid,
                         )
                         step._filled_attestation = signed_attestation
-                        store = _SPEC.on_gossip_attestation(
+                        store = spec.on_gossip_attestation(
                             store,
                             signed_attestation,
                             scheme=LEAN_ENV_TO_SCHEMES[self.lean_env],
@@ -364,7 +362,7 @@ def make_fixture(self) -> Self:
                             key_manager,
                         )
                         step._filled_attestation = signed_aggregated
-                        store = _SPEC.on_gossip_aggregated_attestation(store, signed_aggregated)
+                        store = spec.on_gossip_aggregated_attestation(store, signed_aggregated)
 
                     case _:
                         raise ValueError(f"Step {i}: unknown step type {type(step).__name__}")

packages/testing/src/consensus_testing/test_fixtures/state_transition.py

@@ -17,9 +17,6 @@
 from ..test_types import AggregatedAttestationSpec, BlockSpec, StateExpectation
 from .base import BaseConsensusFixture
 
-_SPEC = LstarSpec()
-"""Active fork spec — stateless, safe to share across all fixture invocations."""
-
 
 class StateTransitionTest(BaseConsensusFixture):
     """
@@ -113,6 +110,7 @@ def make_fixture(self) -> "StateTransitionTest":
         """
         actual_post_state: State | None = None
         exception_raised: Exception | None = None
+        spec = LstarSpec()
 
         # Initialize filled_blocks list that will be populated as we process blocks
         filled_blocks: list[Block] = []
@@ -140,9 +138,9 @@ def make_fixture(self) -> "StateTransitionTest":
                 if cached_state is not None:
                     state = cached_state
                 elif getattr(block_spec, "skip_slot_processing", False):
-                    state = _SPEC.process_block(state, block)
+                    state = spec.process_block(state, block)
                 else:
-                    state = _SPEC.state_transition(
+                    state = spec.state_transition(
                         state,
                         block=block,
                         valid_signatures=True,
@@ -217,7 +215,7 @@ def _build_block_from_spec(
         # Advance slots unless the spec intentionally skips slot processing.
         slot_advanced_state: State | None = None
         if not spec.skip_slot_processing:
-            slot_advanced_state = _SPEC.process_slots(state, spec.slot)
+            slot_advanced_state = LstarSpec().process_slots(state, spec.slot)
 
         # Resolve the parent root.
         # Default: latest block header from the slot-advanced state.
@@ -260,7 +258,7 @@ def _build_block_from_spec(
 
             known_block_roots = frozenset(hash_tree_root(b) for b in block_registry.values())
 
-            block, post_state, _, _ = _SPEC.build_block(
+            block, post_state, _, _ = LstarSpec().build_block(
                 state,
                 slot=spec.slot,
                 proposer_index=proposer_index,
@@ -295,8 +293,8 @@ def _build_block_from_spec(
             # The body changed, so re-run the transition to get the correct
             # post-state and state root.
             if post_state is not None:
-                post_state = _SPEC.process_slots(state, spec.slot)
-                post_state = _SPEC.process_block(post_state, block)
+                post_state = LstarSpec().process_slots(state, spec.slot)
+                post_state = LstarSpec().process_block(post_state, block)
                 block = block.model_copy(update={"state_root": hash_tree_root(post_state)})
 
         return block, post_state

packages/testing/src/consensus_testing/test_fixtures/verify_signatures.py

@@ -22,9 +22,6 @@
 from ..test_types import BlockSpec
 from .base import BaseConsensusFixture
 
-_SPEC = LstarSpec()
-"""Active fork spec — stateless, safe to share across all fixture invocations."""
-
 
 class VerifySignaturesTest(BaseConsensusFixture):
     """
@@ -115,7 +112,7 @@ def make_fixture(self) -> VerifySignaturesTest:
 
         # Verify signatures
         try:
-            _SPEC.verify_signatures(signed_block, self.anchor_state.validators)
+            LstarSpec().verify_signatures(signed_block, self.anchor_state.validators)
         except AssertionError as e:
             exception_raised = e
             # If we expect an exception, this is fine

packages/testing/src/consensus_testing/test_types/block_spec.py

@@ -32,9 +32,6 @@
 from ..keys import LEAN_ENV_TO_SCHEMES, XmssKeyManager, create_dummy_signature
 from .aggregated_attestation_spec import AggregatedAttestationSpec
 
-_SPEC = LstarSpec()
-"""Active fork spec — stateless, safe to share across all spec invocations."""
-
 
 class BlockSpec(CamelModel):
     """
@@ -294,6 +291,7 @@ def build_signed_block(
         Returns:
             Complete signed block with all attestation and proposer signatures.
         """
+        spec = LstarSpec()
         proposer_index = self.resolve_proposer_index(len(state.validators))
 
         # Build a genesis block registry so attestation specs can resolve labels.
@@ -308,7 +306,7 @@ def build_signed_block(
 
         # Resolve the parent root.
         # The default is the latest block header from the slot-advanced state.
-        parent_state = _SPEC.process_slots(state, self.slot)
+        parent_state = spec.process_slots(state, self.slot)
         parent_root = self.resolve_parent_root(
             block_registry,
             default_root=hash_tree_root(parent_state.latest_block_header),
@@ -364,7 +362,7 @@ def build_signed_block(
             for agg_att, proof in zip(aggregated_attestations, attestation_sigs.data, strict=True)
         }
 
-        final_block, _, _, aggregated_signatures = _SPEC.build_block(
+        final_block, _, _, aggregated_signatures = spec.build_block(
             state,
             slot=self.slot,
             proposer_index=proposer_index,
@@ -405,6 +403,7 @@ def build_signed_block_with_store(
         Returns:
             Complete signed block ready for Store processing.
         """
+        spec = LstarSpec()
         proposer_index = self.resolve_proposer_index(len(store.states[store.head].validators))
 
         # Resolve parent block.
@@ -429,7 +428,7 @@ def build_signed_block_with_store(
         # check rejects votes whose slot has not yet started locally.
         block_slot_interval = Interval.from_slot(self.slot)
         if store.time < block_slot_interval:
-            store, _ = _SPEC.on_tick(
+            store, _ = spec.on_tick(
                 store, block_slot_interval, has_proposal=True, is_aggregator=True
             )
 
@@ -442,7 +441,7 @@ def build_signed_block_with_store(
                 or (signature := sigs_for_data.get(attestation.validator_id)) is None
             ):
                 continue
-            store = _SPEC.on_gossip_attestation(
+            store = spec.on_gossip_attestation(
                 store,
                 SignedAttestation(
                     validator_id=attestation.validator_id,
@@ -454,11 +453,11 @@ def build_signed_block_with_store(
             )
 
         # Trigger Store aggregation to merge gossip signatures into known payloads.
-        aggregation_store, _ = store.aggregate()
-        merged_store = aggregation_store.accept_new_attestations()
+        aggregation_store, _ = spec.aggregate(store)
+        merged_store = spec.accept_new_attestations(aggregation_store)
 
         # Build the block through the spec's State.build_block().
-        final_block, _, _, block_proofs = _SPEC.build_block(
+        final_block, _, _, block_proofs = spec.build_block(
             parent_state,
             slot=self.slot,
             proposer_index=proposer_index,
@@ -470,9 +469,9 @@ def build_signed_block_with_store(
         # Append forced attestations that bypass the builder's MAX cap.
         # Each entry is signed and aggregated so the block carries valid proofs.
         if self.forced_attestations:
-            for spec in self.forced_attestations:
-                att_data = spec.build_attestation_data(block_registry, parent_state)
-                proof = key_manager.sign_and_aggregate(spec.validator_ids, att_data)
+            for att_spec in self.forced_attestations:
+                att_data = att_spec.build_attestation_data(block_registry, parent_state)
+                proof = key_manager.sign_and_aggregate(att_spec.validator_ids, att_data)
                 block_proofs.append(proof)
                 final_block = final_block.model_copy(
                     update={
@@ -483,7 +482,7 @@ def build_signed_block_with_store(
                                         *final_block.body.attestations.data,
                                         AggregatedAttestation(
                                             aggregation_bits=ValidatorIndices(
-                                                data=spec.validator_ids,
+                                                data=att_spec.validator_ids,
                                             ).to_aggregation_bits(),
                                             data=att_data,
                                         ),
@@ -495,8 +494,8 @@ def build_signed_block_with_store(
                 )
 
             # Recompute state root with the modified body.
-            post_state = _SPEC.process_slots(parent_state, self.slot)
-            post_state = _SPEC.process_block(post_state, final_block)
+            post_state = spec.process_slots(parent_state, self.slot)
+            post_state = spec.process_block(post_state, final_block)
             final_block = final_block.model_copy(update={"state_root": hash_tree_root(post_state)})
 
         return self._sign_block(final_block, block_proofs, proposer_index, key_manager)

packages/testing/src/consensus_testing/test_types/gossip_attestation_spec.py

@@ -12,9 +12,6 @@
 from ..keys import XmssKeyManager, create_dummy_signature
 from .utils import resolve_checkpoint
 
-_SPEC = LstarSpec()
-"""Active fork spec — stateless, safe to share across all spec invocations."""
-
 
 class GossipAttestationSpec(CamelModel):
     """
@@ -204,7 +201,7 @@ def build_signed(
             attestation_data = self.build_attestation_data(block_registry, anchor_block)
         else:
             # Honest path: use the Store's own attestation data production.
-            attestation_data = _SPEC.produce_attestation_data(store, self.slot)
+            attestation_data = LstarSpec().produce_attestation_data(store, self.slot)
 
         signature = (
             key_manager.sign_attestation_data(self.validator_id, attestation_data)