dev: add append_logs util (#773)

cairo/ethereum/cancun/vm/instructions/block.cairo

@@ -5,12 +5,14 @@ from starkware.cairo.common.math_cmp import is_nn, is_in_range
 
 from ethereum_types.numeric import U256, U256Struct, Uint
 from ethereum.cancun.vm import Evm, EvmImpl
+from ethereum.cancun.blocks import TupleLog, TupleLogStruct
 from ethereum.exceptions import EthereumException
 from ethereum.cancun.vm.gas import charge_gas, GasConstants
 from ethereum.cancun.vm.stack import Stack, pop, push
 from ethereum.utils.numeric import U256_from_be_bytes32
 from legacy.utils.bytes import felt_to_bytes20_little
 from legacy.utils.utils import Helpers
+from starkware.cairo.common.memcpy import memcpy
 
 // @notice Get the hash of one of the 256 most recent complete blocks
 func block_hash{
@@ -303,3 +305,16 @@ namespace Internals {
         return ok;
     }
 }
+
+func _append_logs{logs: TupleLog}(new_logs: TupleLog) {
+    let src_len = new_logs.value.len;
+    if (src_len == 0) {
+        return ();
+    }
+    let len = logs.value.len;
+    let dst = logs.value.data + len;
+    let src = new_logs.value.data;
+    memcpy(dst, src, src_len);
+    tempvar logs = TupleLog(new TupleLogStruct(data=logs.value.data, len=len + src_len));
+    return ();
+}

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

@@ -1,3 +1,6 @@
+from typing import Tuple
+
+from ethereum.cancun.blocks import Log
 from ethereum.cancun.state import TransientStorage
 from ethereum.cancun.vm import Environment, Evm
 from ethereum.cancun.vm.instructions.block import (
@@ -152,3 +155,19 @@ def test_chain_id(self, cairo_run, evm: Evm):
 
         chain_id(evm)
         assert evm == cairo_result
+
+
+class TestUtils:
+    @given(logs=..., new_logs=...)
+    def test_append_logs(
+        self, cairo_run, logs: Tuple[Log, ...], new_logs: Tuple[Log, ...]
+    ):
+        try:
+            cairo_result = cairo_run("_append_logs", logs, new_logs)
+        except EthereumException as cairo_error:
+            with strict_raises(type(cairo_error)):
+                logs += new_logs
+            return
+
+        logs += new_logs
+        assert logs == cairo_result

cairo/tests/utils/strategies.py

@@ -514,7 +514,7 @@ def register_type_strategies():
     st.register_type_strategy(Account, account_strategy)
     st.register_type_strategy(Withdrawal, st.builds(Withdrawal))
     st.register_type_strategy(Header, st.builds(Header))
-    st.register_type_strategy(Log, st.builds(Log))
+    st.register_type_strategy(Log, st.builds(Log, data=small_bytes))
     st.register_type_strategy(Receipt, st.builds(Receipt))
     st.register_type_strategy(
         LegacyTransaction, st.builds(LegacyTransaction, data=small_bytes)