fix: custom toml parsing of Option values

z2/src/chain.rs

@@ -165,9 +165,7 @@ impl Chain {
             Self::Zq2ProtoTestnet => ContractUpgradesBlockHeights {
                 deposit_v3: Some(8406000),
             },
-            _ => ContractUpgradesBlockHeights {
-                deposit_v3: Some(0),
-            },
+            _ => ContractUpgradesBlockHeights::default(),
         }
     }
 

z2/src/chain/node.rs

@@ -612,8 +612,7 @@ impl ChainNode {
         );
         ctx.insert(
             "contract_upgrade_block_heights",
-            &serde_json::from_value::<toml::Value>(json!(contract_upgrade_block_heights))?
-                .to_string(),
+            &contract_upgrade_block_heights.to_toml().to_string(),
         );
         // convert json to toml formatting
         let toml_servers: toml::Value = serde_json::from_value(api_servers)?;

zilliqa/src/cfg.rs

@@ -5,6 +5,7 @@ use anyhow::{anyhow, Result};
 use libp2p::{Multiaddr, PeerId};
 use rand::{distributions::Alphanumeric, Rng};
 use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
+use serde_json::json;
 
 use crate::{
     crypto::{Hash, NodePublicKey},
@@ -536,3 +537,24 @@ pub fn total_native_token_supply_default() -> Amount {
 pub struct ContractUpgradesBlockHeights {
     pub deposit_v3: Option<u64>,
 }
+
+impl ContractUpgradesBlockHeights {
+    // toml doesnt like Option types. Map items in struct and remove keys for None values
+    pub fn to_toml(&self) -> toml::Value {
+        toml::Value::Table(
+            json!(self)
+                .as_object()
+                .unwrap()
+                .clone()
+                .into_iter()
+                .filter_map(|(k, v)| {
+                    if v.is_null() {
+                        None // Skip null values
+                    } else {
+                        Some((k, toml::Value::Integer(v.as_u64().unwrap() as i64)))
+                    }
+                })
+                .collect(),
+        )
+    }
+}