From 63d984b2ffe2d64851628e7dfd4f58e316650b8b Mon Sep 17 00:00:00 2001
From: Marvin Michael Nkut <marvinnkut@gmail.com>
Date: Thu, 28 May 2026 05:00:49 +0000
Subject: [PATCH] feat: implement WASM upgradeable contract pattern (#34)
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- Import BytesN from soroban_sdk
- Add admin_key() storage helper (instance storage)
- Add initialize(admin) — sets admin once, panics if called again
- Add upgrade(new_wasm_hash) — requires admin auth, calls update_current_contract_wasm
- Tests: initialize_twice_panics, upgrade_preserves_storage, upgrade_requires_admin_auth
- All 10 tests pass, clippy clean

Closes #34
---
 contracts/split/src/lib.rs  | 27 ++++++++++++++-
 contracts/split/src/test.rs | 68 +++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+), 1 deletion(-)

diff --git a/contracts/split/src/lib.rs b/contracts/split/src/lib.rs
index 9bf6632..9652e95 100644
--- a/contracts/split/src/lib.rs
+++ b/contracts/split/src/lib.rs
@@ -12,7 +12,7 @@ mod types;
 #[cfg(test)]
 mod test;
 
-use soroban_sdk::{contract, contractimpl, symbol_short, token, Address, Env, Symbol, Vec};
+use soroban_sdk::{contract, contractimpl, symbol_short, token, Address, BytesN, Env, Symbol, Vec};
 use types::{Invoice, InvoiceStatus, Payment};
 
 // ---------------------------------------------------------------------------
@@ -24,6 +24,11 @@ fn counter_key() -> Symbol {
     symbol_short!("counter")
 }
 
+/// Storage key for the contract admin address.
+fn admin_key() -> Symbol {
+    symbol_short!("admin")
+}
+
 /// Composite storage key for an invoice: (symbol, id).
 fn invoice_key(id: u64) -> (Symbol, u64) {
     (symbol_short!("inv"), id)
@@ -51,6 +56,26 @@ pub struct SplitContract;
 
 #[contractimpl]
 impl SplitContract {
+    /// Set the contract admin. Can only be called once.
+    pub fn initialize(env: Env, admin: Address) {
+        assert!(
+            !env.storage().instance().has(&admin_key()),
+            "already initialized"
+        );
+        env.storage().instance().set(&admin_key(), &admin);
+    }
+
+    /// Upgrade the contract WASM. Requires admin auth.
+    pub fn upgrade(env: Env, new_wasm_hash: BytesN<32>) {
+        let admin: Address = env
+            .storage()
+            .instance()
+            .get(&admin_key())
+            .expect("not initialized");
+        admin.require_auth();
+        env.deployer().update_current_contract_wasm(new_wasm_hash);
+    }
+
     /// Create a new invoice.
     ///
     /// # Arguments
diff --git a/contracts/split/src/test.rs b/contracts/split/src/test.rs
index 7d326a2..cf16d73 100644
--- a/contracts/split/src/test.rs
+++ b/contracts/split/src/test.rs
@@ -250,3 +250,71 @@ fn test_multi_recipient_release() {
     assert_eq!(tk.balance(&r2), 200);
     assert_eq!(tk.balance(&r3), 300);
 }
+
+// Use a real wasm fixture for upgrade tests.
+const TEST_WASM: &[u8] = include_bytes!(
+    "/home/codespace/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/soroban-sdk-22.0.11/test_wasms/test_contract_data.wasm"
+);
+
+#[test]
+#[should_panic(expected = "already initialized")]
+fn test_initialize_twice_panics() {
+    let (env, contract_id, _token_id) = setup();
+    let c = client(&env, &contract_id);
+    let admin = Address::generate(&env);
+    c.initialize(&admin);
+    c.initialize(&admin);
+}
+
+#[test]
+fn test_upgrade_preserves_storage() {
+    let (env, contract_id, token_id) = setup();
+    let c = client(&env, &contract_id);
+
+    let admin = Address::generate(&env);
+    c.initialize(&admin);
+
+    // Create an invoice so there's state to preserve.
+    let creator = Address::generate(&env);
+    let recipient = Address::generate(&env);
+    let mut recipients = Vec::new(&env);
+    recipients.push_back(recipient.clone());
+    let mut amounts = Vec::new(&env);
+    amounts.push_back(100_i128);
+    env.ledger().set_timestamp(1_000);
+    let id = c.create_invoice(&creator, &recipients, &amounts, &token_id, &9_999_u64);
+
+    // Verify invoice exists before upgrade.
+    let invoice_before = c.get_invoice(&id);
+    assert_eq!(invoice_before.status, InvoiceStatus::Pending);
+
+    // Upload a wasm blob and upgrade — storage keys survive the wasm swap.
+    let new_wasm_hash = env
+        .deployer()
+        .upload_contract_wasm(soroban_sdk::Bytes::from_slice(&env, TEST_WASM));
+    c.upgrade(&new_wasm_hash);
+
+    // Verify the invoice storage key is still present after the upgrade.
+    let storage_key = (soroban_sdk::symbol_short!("inv"), id);
+    assert!(env.as_contract(&contract_id, || {
+        env.storage().persistent().has(&storage_key)
+    }));
+}
+
+#[test]
+#[should_panic]
+fn test_upgrade_requires_admin_auth() {
+    let (env, contract_id, _token_id) = setup();
+    let c = client(&env, &contract_id);
+
+    let admin = Address::generate(&env);
+    c.initialize(&admin);
+
+    let new_wasm_hash = env
+        .deployer()
+        .upload_contract_wasm(soroban_sdk::Bytes::from_slice(&env, TEST_WASM));
+
+    // Disable mock auths — upgrade should panic because admin auth is not provided.
+    env.set_auths(&[]);
+    c.upgrade(&new_wasm_hash);
+}