fix: original storage tries arg gen (#471)

Co-authored-by: Oba <obatirou@gmail.com>

cairo/tests/ethereum/cancun/vm/instructions/test_block.py

@@ -19,6 +19,7 @@
     BLOCK_HASHES_LIST,
     address,
     bytes32,
+    empty_state,
     uint,
     uint64,
     uint256,
@@ -53,7 +54,7 @@
         gas_price=st.just(Uint(0)),
         time=uint256,
         prev_randao=bytes32,
-        state=st.just(State()),
+        state=empty_state,
         chain_id=uint64,
         excess_blob_gas=st.just(U64(0)),
         blob_versioned_hashes=st.just(()),

cairo/tests/utils/args_gen.py

@@ -620,7 +620,11 @@ def _gen_arg(
             # In case of a Trie, we need to put the original_storage_tries (state._snapshots[0][1]) in a
             # special field of the State. We want easy access / overrides to this specific snapshot in
             # Cairo, as each `sstore` performs an update of this original trie.
-            data.append(data[1])
+            # The state strategy should always generate a valid snapshots[0], corresponding to the initial state.
+            snapshots_ptr = segments.memory.get(data[2])
+            snapshots0_ptr = segments.memory.get(snapshots_ptr)
+            snapshots0_storage_tries_ptr = segments.memory.get(snapshots0_ptr + 1)
+            data.append(snapshots0_storage_tries_ptr)
 
         segments.load_data(struct_ptr, data)
 

cairo/tests/utils/evm_builder.py

@@ -2,11 +2,12 @@
 from ethereum_types.numeric import U64, U256, Bytes32, Uint
 from hypothesis import strategies as st
 
-from ethereum.cancun.state import State, TransientStorage
+from ethereum.cancun.state import TransientStorage
 from ethereum.exceptions import EthereumException
 from tests.utils.args_gen import Environment, Evm, Message, Stack
 from tests.utils.strategies import (
     Memory,
+    empty_state,
     environment_lite,
     gas_left,
     memory_lite,
@@ -31,7 +32,7 @@
     gas_price=st.just(Uint(0)),
     time=st.just(U256(0)),
     prev_randao=st.just(Bytes32(b"\x00" * 32)),
-    state=st.just(State()),
+    state=empty_state,
     chain_id=st.just(U64(0)),
     excess_blob_gas=st.just(U64(0)),
     blob_versioned_hashes=st.just(()),

cairo/tests/utils/strategies.py

@@ -354,6 +354,20 @@ def tuple_strategy(thing):
 
 
 # Fork
+# A strategy for an empty state - the tries have no data.
+empty_state = st.builds(
+    State,
+    _main_trie=st.just(
+        Trie[Address, Optional[Account]](secured=True, default=None, _data={})
+    ),
+    _storage_tries=st.just({}),
+    _snapshots=st.just(
+        [(Trie[Address, Optional[Account]](secured=True, default=None, _data={}), {})]
+    ),
+    created_accounts=st.just(set()),
+)
+
+
 state = st.lists(address, max_size=MAX_ADDRESS_SET_SIZE, unique=True).flatmap(
     lambda addresses: st.builds(
         State,