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integration-tests/src/tests/client/features/wallet_contract.rs

@@ -66,6 +66,7 @@ fn view_request(env: &TestEnv, request: QueryRequest) -> QueryResponse {
         .unwrap()
 }
 
+/// Tests that ETH-implicit account is created correctly, with Wallet Contract hash.
 #[test]
 fn test_eth_implicit_account_creation() {
     if !checked_feature!("stable", EthImplicitAccounts, PROTOCOL_VERSION) {
@@ -97,7 +98,8 @@ fn test_eth_implicit_account_creation() {
 
     let magic_bytes = wallet_contract_magic_bytes();
 
-    // Verify the ETH-implicit account has zero balance, wallet contract hash, and its storage fits within zero balance account limit.
+    // Verify the ETH-implicit account has zero balance and appropriate code hash.
+    // Check that the account storage fits within zero balance account limit.
     let request = QueryRequest::ViewAccount { account_id: eth_implicit_account_id.clone() };
     match view_request(&env, request).kind {
         QueryResponseKind::ViewAccount(view) => {

runtime/near-wallet-contract/README.md

@@ -4,8 +4,8 @@ See https://github.com/near/NEPs/issues/518.
 
 Must not use in production!
 
-To use the contract you need to make sure that this crate was compiled.
-The contract is built via `build.rs` and WASM file is generated to the `./res` directory.
-
 If you want to use the contract from nearcore, add this crate as a dependency
 to the Cargo.toml and use `near_wallet_contract::wallet_contract()`.
+
+The contract can be rebuilt by `build.rs` if you run `cargo build` with `--features build_wallet_contract` flag.
+It would generate WASM file and save it to the `./res` directory.

runtime/runtime/src/actions.rs

@@ -56,9 +56,8 @@ fn get_contract_code(
     if checked_feature!("stable", EthImplicitAccounts, protocol_version)
         && account_id.get_account_type() == AccountType::EthImplicitAccount
     {
-        let contract = wallet_contract();
         debug_assert!(code_hash == *wallet_contract_magic_bytes().hash());
-        return Ok(Some(contract));
+        return Ok(Some(wallet_contract()));
     }
     runtime_ext.get_code(code_hash).map(|option| option.map(Arc::new))
 }
@@ -500,17 +499,17 @@ pub(crate) fn action_implicit_account_creation_transfer(
         // It holds because in the only calling site, we've checked the permissions before.
         AccountType::EthImplicitAccount => {
             if checked_feature!("stable", EthImplicitAccounts, current_protocol_version) {
-                // near[wallet contract hash]
+                // We deploy "near[wallet contract hash]" magic bytes as the contract code,
+                // to mark that this is a neard-defined contract. It will not be used on a function call.
+                // Instead, neard-defined Wallet Contract implementation will be used.
                 let magic_bytes = wallet_contract_magic_bytes();
 
                 let storage_usage = fee_config.storage_usage_config.num_bytes_account
                     + magic_bytes.code().len() as u64
                     + fee_config.storage_usage_config.num_extra_bytes_record;
 
-                // We do not literally deploy `Wallet Contract`, just store a reference to the contract.
                 *account =
                     Some(Account::new(transfer.deposit, 0, *magic_bytes.hash(), storage_usage));
-
                 set_code(state_update, account_id.clone(), &magic_bytes);
 
                 // Precompile Wallet Contract and store result (compiled code or error) in the database.