From 9edf1cb235cb33ef5eac81bd252fc711dcd929eb Mon Sep 17 00:00:00 2001
From: benesjan <janbenes1234@gmail.com>
Date: Tue, 27 Feb 2024 09:41:04 +0000
Subject: [PATCH] WIP

---
 .../aztec-nr/aztec/src/state_vars.nr          |  2 ++
 .../aztec/src/state_vars/public_immutable.nr  | 27 ++++++++++++-------
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/noir-projects/aztec-nr/aztec/src/state_vars.nr b/noir-projects/aztec-nr/aztec/src/state_vars.nr
index 4201723eb07..f10b2ac487e 100644
--- a/noir-projects/aztec-nr/aztec/src/state_vars.nr
+++ b/noir-projects/aztec-nr/aztec/src/state_vars.nr
@@ -1,6 +1,7 @@
 mod map;
 mod private_immutable;
 mod private_mutable;
+mod public_immutable;
 mod public_mutable;
 mod private_set;
 mod shared_immutable;
@@ -9,6 +10,7 @@ mod storage;
 use crate::state_vars::map::Map;
 use crate::state_vars::private_immutable::PrivateImmutable;
 use crate::state_vars::private_mutable::PrivateMutable;
+use crate::state_vars::public_immutable::PublicImmutable;
 use crate::state_vars::public_mutable::PublicMutable;
 use crate::state_vars::private_set::PrivateSet;
 use crate::state_vars::shared_immutable::SharedImmutable;
diff --git a/noir-projects/aztec-nr/aztec/src/state_vars/public_immutable.nr b/noir-projects/aztec-nr/aztec/src/state_vars/public_immutable.nr
index bbda1e0f509..17dd73efed6 100644
--- a/noir-projects/aztec-nr/aztec/src/state_vars/public_immutable.nr
+++ b/noir-projects/aztec-nr/aztec/src/state_vars/public_immutable.nr
@@ -1,9 +1,5 @@
-use crate::context::{Context};
-use crate::oracle::storage::storage_read;
-use crate::oracle::storage::storage_write;
-use dep::std::option::Option;
-use dep::protocol_types::traits::{Deserialize, Serialize};
-use crate::state_vars::storage::Storage;
+use crate::{context::Context, oracle::{storage::{storage_read, storage_write}}, state_vars::storage::Storage};
+use dep::protocol_types::{constants::INITIALIZATION_SLOT_SEPARATOR, traits::{Deserialize, Serialize}};
 
 // docs:start:public_immutable_struct
 struct PublicImmutable<T> {
@@ -29,10 +25,23 @@ impl<T> PublicImmutable<T> {
     // docs:start:public_immutable_struct_write
     pub fn initialize<T_SERIALIZED_LEN>(self, value: T) where T: Serialize<T_SERIALIZED_LEN> {
         assert(
-            self.context.private.is_none(), "PublicImmutable initialization only supported in public functions"
+            self.context.private.is_none(), "PublicImmutable can only be initialized from public functions"
         );
-        let fields = T::serialize(value);
-        storage_write(self.storage_slot, fields);
+        // TODO(#4738): Uncomment the following assert
+        // assert(
+        //     self.context.public.unwrap_unchecked().is_deployment(), "PublicImmutable can only be initialized during contract deployment"
+        // );
+
+        // We check that the struct is not yet initialized by checking if the initialization slot is 0
+        let initialization_slot = INITIALIZATION_SLOT_SEPARATOR + self.storage_slot;
+        let fields_read: [Field; 1] = storage_read(initialization_slot);
+        assert(fields_read[0] == 0, "PublicImmutable already initialized");
+
+        // We populate the initialization slot with a non-zero value to indicate that the struct is initialized
+        storage_write(initialization_slot, [0xdead]);
+
+        let fields_write = T::serialize(value);
+        storage_write(self.storage_slot, fields_write);
     }
     // docs:end:public_immutable_struct_write