feat: add initializer chain_id

cairo_zero/kakarot/kakarot.cairo

@@ -70,6 +70,16 @@ func unpause{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}()
     return ();
 }
 
+// @notice chain_id initializer
+@external
+func initialize_chain_id{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(
+    chain_id: felt
+) {
+    Ownable.assert_only_owner();
+    Kakarot.initialize_chain_id(chain_id);
+    return ();
+}
+
 // Constructor
 @constructor
 func constructor{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(

cairo_zero/kakarot/library.cairo

@@ -414,4 +414,17 @@ namespace Kakarot {
             0, l1_sender, to, 2100000000, 1, value_u256, data_len, data, 0, access_list
         );
     }
+
+    // @notice Initialize the chain ID
+    // @param chain_id The chain ID
+    func initialize_chain_id{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}(
+        chain_id: felt
+    ) {
+        with_attr error_message("Kakarot: chain_id already initialized") {
+            let (current_chain_id) = Kakarot_chain_id.read();
+            assert current_chain_id = 0;
+        }
+        Kakarot_chain_id.write(chain_id);
+        return ();
+    }
 }

cairo_zero/tests/src/kakarot/test_kakarot.cairo

@@ -23,6 +23,7 @@ from kakarot.kakarot import (
     handle_l1_message,
     pause,
     unpause,
+    initialize_chain_id,
 )
 from kakarot.model import model
 from kakarot.account import Account
@@ -280,3 +281,10 @@ func test__unpause{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_p
     unpause();
     return ();
 }
+
+func test__initialize_chain_id{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr}() {
+    tempvar chain_id;
+    %{ ids.chain_id = program_input["chain_id"] %}
+    initialize_chain_id(chain_id);
+    return ();
+}

cairo_zero/tests/src/kakarot/test_kakarot.py

@@ -97,7 +97,6 @@ def test_should_pause(self, cairo_run):
             )
 
     class TestUnpause:
-
         @SyscallHandler.patch("Ownable_owner", 0xDEAD)
         def test_should_assert_only_owner(self, cairo_run):
             with cairo_error(message="Ownable: caller is not the owner"):
@@ -185,6 +184,31 @@ def test_should_set_prev_randao(self, cairo_run):
                 value=prev_randao,
             )
 
+    class TestInitializeChainId:
+        @SyscallHandler.patch("Ownable_owner", 0xDEAD)
+        def test_should_assert_only_owner(self, cairo_run):
+            with cairo_error(message="Ownable: caller is not the owner"):
+                cairo_run("test__initialize_chain_id", chain_id=0xABC)
+
+        @SyscallHandler.patch("Ownable_owner", SyscallHandler.caller_address)
+        def test_should_initialize_chain_id(self, cairo_run):
+            chain_id = 0x123
+
+            cairo_run("test__initialize_chain_id", chain_id=chain_id)
+            SyscallHandler.mock_storage.assert_any_call(
+                address=get_storage_var_address("Kakarot_chain_id"),
+                value=chain_id,
+            )
+
+        @SyscallHandler.patch("Ownable_owner", SyscallHandler.caller_address)
+        def test_should_fail_initialize_chain_id_twice(self, cairo_run):
+            chain_id = 0x123
+            with (
+                cairo_error(message="Kakarot: chain_id already initialized"),
+                SyscallHandler.patch("Kakarot_chain_id", chain_id),
+            ):
+                cairo_run("test__initialize_chain_id", chain_id=chain_id)
+
     class TestBlockGasLimit:
         @SyscallHandler.patch("Ownable_owner", 0xDEAD)
         def test_should_assert_only_owner(self, cairo_run):