fix: make initializeNewAccount polymorphic so subclasses get their own runtime type

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [UNRELEASED]
 
+### Bug Fixes
+
+- **`SafeAccountV1_5_0_M_0_3_0.initializeNewAccount` returns the right runtime type.** The subclass factory delegated to `SafeAccountV0_3_0.initializeNewAccount`, which hard-coded `new SafeAccountV0_3_0(...)`, so the returned instance failed `instanceof SafeAccountV1_5_0_M_0_3_0` and lost subclass behavior. The base factory now instantiates polymorphically through `new this(...)`, so any subclass (including consumer-defined ones) gets its own type back. (#116)
+
 ## 0.4.0
 
 ### New Features

src/account/Safe/SafeAccountV0_3_0.ts

@@ -87,17 +87,22 @@ export class SafeAccountV0_3_0 extends SafeAccount {
 	 * The account address is deterministically computed but not yet deployed on-chain.
 	 * The first UserOperation sent will deploy it automatically via factory data.
 	 *
+	 * Instantiates through `new this(...)`, so subclasses calling this
+	 * factory (directly or via `super`) get an instance of the subclass,
+	 * not a plain SafeAccountV0_3_0.
+	 *
 	 * @param owners - Array of owner signers (at least one required)
 	 * @param overrides - Override default initialization values
-	 * @returns A SafeAccountV0_3_0 instance with factory data set for deployment
+	 * @returns An instance of the calling class with factory data set for deployment
 	 *
 	 * @example
 	 * const smartAccount = SafeAccountV0_3_0.initializeNewAccount(["0xOwnerAddress"]);
 	 */
-	public static initializeNewAccount(
+	public static initializeNewAccount<T extends typeof SafeAccountV0_3_0>(
+		this: T,
 		owners: Signer[],
 		overrides: InitCodeOverrides = {},
-	): SafeAccountV0_3_0 {
+	): InstanceType<T> {
 		let isInitWebAuthn = false;
 		let x = 0n;
 		let y = 0n;
@@ -122,7 +127,8 @@ export class SafeAccountV0_3_0 extends SafeAccount {
 				overrides.safeModuleSetupAddress ?? SafeAccountV0_3_0.DEFAULT_SAFE_MODULE_SETUP_ADDRESS,
 			);
 
-		const safe = new SafeAccountV0_3_0(accountAddress, {
+		// biome-ignore lint/complexity/noThisInStatic: polymorphic factory; subclasses must get their own type back
+		const safe: SafeAccountV0_3_0 = new this(accountAddress, {
 			safe4337ModuleAddress: overrides.safe4337ModuleAddress,
 			entrypointAddress: overrides.entrypointAddress,
 			onChainIdentifierParams: overrides.onChainIdentifierParams,
@@ -137,7 +143,7 @@ export class SafeAccountV0_3_0 extends SafeAccount {
 			safe.y = y;
 		}
 
-		return safe;
+		return safe as InstanceType<T>;
 	}
 
 	/**

src/account/Safe/SafeAccountV1_5_0_M_0_3_0.ts

@@ -97,10 +97,11 @@ export class SafeAccountV1_5_0_M_0_3_0 extends SafeAccountV0_3_0 {
 	 * @example
 	 * const smartAccount = SafeAccountV1_5_0_M_0_3_0.initializeNewAccount(["0xOwnerAddress"]);
 	 */
-	public static initializeNewAccount(
+	public static initializeNewAccount<T extends typeof SafeAccountV0_3_0>(
+		this: T,
 		owners: Signer[],
 		overrides: InitCodeOverrides = {},
-	): SafeAccountV1_5_0_M_0_3_0 {
+	): InstanceType<T> {
 		const modOverrides = {
 			...overrides,
 			safeAccountSingleton: overrides.safeAccountSingleton ?? Safe_L2_V1_5_0,
@@ -111,7 +112,11 @@ export class SafeAccountV1_5_0_M_0_3_0 extends SafeAccountV0_3_0 {
 				overrides.eip7212WebAuthnContractVerifierForSharedSigner ??
 				SafeAccountV1_5_0_M_0_3_0.DEFAULT_WEB_AUTHN_CONTRACT_VERIFIER,
 		};
-		return SafeAccountV0_3_0.initializeNewAccount(owners, modOverrides);
+		// `super` keeps `this` bound to the calling class, so the base
+		// factory's `new this(...)` constructs an instance of this class
+		// (SafeAccountV1_5_0_M_0_3_0 or a subclass), not SafeAccountV0_3_0.
+		// biome-ignore lint/complexity/noThisInStatic: polymorphic factory dispatch through super
+		return super.initializeNewAccount(owners, modOverrides) as InstanceType<T>;
 	}
 
 	/**

test/safe/initializeNewAccountRuntimeType.test.js

@@ -0,0 +1,32 @@
+// Unit tests for issue #116: SafeAccountV1_5_0_M_0_3_0.initializeNewAccount
+// must return a SafeAccountV1_5_0_M_0_3_0 instance at runtime, not a plain
+// SafeAccountV0_3_0. No network required.
+
+const ak = require("../../dist/index.cjs");
+
+const OWNER = "0x2222222222222222222222222222222222222222";
+
+describe("initializeNewAccount runtime type (#116)", () => {
+	test("SafeAccountV1_5_0_M_0_3_0.initializeNewAccount returns a SafeAccountV1_5_0_M_0_3_0", () => {
+		const account = ak.SafeAccountV1_5_0_M_0_3_0.initializeNewAccount([OWNER]);
+		expect(account).toBeInstanceOf(ak.SafeAccountV1_5_0_M_0_3_0);
+	});
+
+	test("instance address matches the class's createAccountAddress (v1.5.0 singleton)", () => {
+		const account = ak.SafeAccountV1_5_0_M_0_3_0.initializeNewAccount([OWNER]);
+		expect(account.accountAddress).toBe(ak.SafeAccountV1_5_0_M_0_3_0.createAccountAddress([OWNER]));
+	});
+
+	test("SafeAccountV0_3_0.initializeNewAccount still returns a plain SafeAccountV0_3_0", () => {
+		const account = ak.SafeAccountV0_3_0.initializeNewAccount([OWNER]);
+		expect(account).toBeInstanceOf(ak.SafeAccountV0_3_0);
+		expect(account).not.toBeInstanceOf(ak.SafeAccountV1_5_0_M_0_3_0);
+		expect(account.accountAddress).toBe(ak.SafeAccountV0_3_0.createAccountAddress([OWNER]));
+	});
+
+	test("a consumer subclass inheriting the factory gets its own type back", () => {
+		class CustomSafe extends ak.SafeAccountV0_3_0 {}
+		const account = CustomSafe.initializeNewAccount([OWNER]);
+		expect(account).toBeInstanceOf(CustomSafe);
+	});
+});