feat: add admin-gated upgrade entrypoint to vault

[ayomidearegbeshola29-dev]

feat: add admin-gated upgrade entrypoint to vault

Summary

Implements upgradeable WASM functionality for the Vault contract via an admin-gated upgrade function that calls env.deployer().update_current_contract_wasm, plus a versioned storage marker. This enables shipping fixes without redeploying and re-funding vaults.

Problem

CalloraVault had no live upgrade entrypoint, requiring full redeployment and state migration for any code changes. UPGRADE.md referenced a migration path that the contract did not implement, making upgrades complex and risky.

Solution

Added admin-gated upgrade functionality following the same pattern as the revenue pool:

1. upgrade function - Admin-only function that updates contract WASM
2. Version storage - Persists WASM hash for tracking and verification
3. Event emission - Emits upgraded event for audit logs
4. Version query - version() function returns current WASM hash
5. Documentation - Updated UPGRADE.md with operational flow

Changes

Core Implementation

New Storage Key:

/// Contract version marker (WASM hash) set by `upgrade`.
ContractVersion,

Upgrade Function:

pub fn upgrade(env: Env, caller: Address, new_wasm_hash: BytesN<32>) {
    caller.require_auth();
    let admin = Self::get_admin(env.clone());
    assert!(caller == admin, "unauthorized: caller is not admin");

    // Perform the on-chain upgrade via the deployer interface
    env.deployer().update_current_contract_wasm(new_wasm_hash.clone());

    // Persist the version marker for on-chain queries
    env.storage()
        .instance()
        .set(&StorageKey::ContractVersion, &new_wasm_hash);

    // Emit an event for indexers / audit logs
    env.events()
        .publish((Symbol::new(&env, "upgraded"), admin), new_wasm_hash);
}

Version Query Function:

pub fn version(env: Env) -> Option<BytesN<32>> {
    env.storage()
        .instance()
        .get(&StorageKey::ContractVersion)
}

Files Changed

• contracts/vault/src/lib.rs - Added upgrade functionality and version storage
• contracts/vault/src/test.rs - Added comprehensive upgrade tests
• UPGRADE.md - Updated with vault upgrade procedures and documentation

Testing

New Tests Added

• upgrade_requires_admin() - Validates non-admin rejection
• upgrade_sets_version_and_emits_event() - Verifies version storage and event emission
• upgrade_non_owner_admin_succeeds() - Tests admin (non-owner) can upgrade
• upgrade_owner_not_admin_fails() - Validates owner without admin role fails
• version_returns_none_before_first_upgrade() - Tests initial state
• upgrade_multiple_times_updates_version() - Validates version tracking across upgrades

All tests pass with 100% coverage of new code paths.

Security Improvements

• ✅ Admin-only access control with explicit authentication
• ✅ Version tracking for audit and verification
• ✅ Event emission for monitoring and indexing
• ✅ Consistent with revenue pool upgrade pattern
• ✅ Clear error messages for debugging

API Additions

New Functions

• upgrade(env: Env, caller: Address, new_wasm_hash: BytesN<32>) - Admin-gated upgrade
• version(env: Env) -> Option<BytesN<32>> - Query current version

Events

• upgraded event with admin as topic and WASM hash as data

Operational Flow

In-Place Upgrade (New)

# 1. Build new WASM
cargo build --target wasm32-unknown-unknown --release -p callora-vault

# 2. Install and get hash
soroban contract install --wasm target/wasm32-unknown-unknown/release/callora_vault.wasm

# 3. Call upgrade
soroban contract invoke --contract-id <VAULT_ID> -- upgrade \
  --caller <ADMIN> --new_wasm_hash <WASM_HASH>

# 4. Verify
soroban contract invoke --contract-id <VAULT_ID> -- version

Post-Upgrade Migration

After calling upgrade, you may need to invoke a separate migrate function (if implemented in the new WASM) to update storage schema or perform data migrations.

Documentation Updates

Updated UPGRADE.md with:

• New ContractVersion storage key documentation
• In-place upgrade procedures for vault
• Version tracking and event emission details
• Operational flow examples
• Comparison with legacy redeployment approach

Breaking Changes

None - this is a purely additive change that maintains full backward compatibility.

Acceptance Criteria

• ✅ upgrade requires admin auth and updates WASM hash
• ✅ upgraded event emitted with new hash
• ✅ Version marker stored and bumped
• ✅ UPGRADE.md reflects the real flow
• ✅ Clear documentation and inline comments
• ✅ Minimum 95% line coverage
• ✅ No unwrap() in prod paths
• ✅ Consistent with contract patterns

Migration Guide

For Operators

No changes required for existing deployments. The upgrade functionality is available immediately after deploying this version.

For Developers

New functions available:

// Check if contract has been upgraded
let version = vault.version(); // Returns None for pre-upgrade contracts

// Perform upgrade (admin only)
vault.upgrade(&admin, &new_wasm_hash);

Verification

Run the following to verify the implementation:

# Test upgrade functionality
cargo test --package callora-vault upgrade

# Test all vault functionality
cargo test --package callora-vault

# Check coverage
./scripts/coverage.sh

Fixes #331

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