fix(cors): defer parameter resolution in https callables and requests

[inlined]

Description

Fixes an issue where passing a parameterized CORS origin (Expression) to HTTPS functions attempts to evaluate the parameter at global module definition time rather than request runtime. This also updates V1 https.onRequest to accept an options object (HttpsOptions) supporting custom cors configuration, aligning with V2.

Scenarios Tested

• Added unit tests in spec/common/providers/https.spec.ts verifying that resolveCorsOrigin successfully extracts runtime values from StringParam and ListParam Expressions.
• Added unit tests in spec/v1/providers/https.spec.ts verifying V1 onRequest correctly enforces custom CORS options and does not crash when passed an Expression.
• Added unit tests in spec/v2/providers/https.spec.ts verifying passing Expressions to onRequest and onCall CORS options does not cause definition-time crashes.
• Ran the full npm test suite to ensure no regressions.

[gemini-code-assist]

Code Review

This pull request adds support for configuring CORS options using parameter expressions (such as defineString and defineList) in both v1 and v2 HTTPS and callable functions. It introduces a resolveCorsOrigin helper to dynamically resolve these expressions per request and includes comprehensive unit tests. The review feedback highlights a critical bug in src/v1/function-builder.ts where arguments is incorrectly used inside an arrow function, which will cause runtime failures. Additionally, it is recommended to use typeof checks instead of arguments.length in src/v1/providers/https.ts for better robustness and consistency.

[gemini-code-assist]

Using arguments inside an arrow function is a critical bug. Arrow functions do not bind their own arguments object; instead, they inherit it from the enclosing scope (in this case, the get https() getter, which has 0 arguments). Consequently, arguments.length === 1 will always evaluate to false, causing the function to incorrectly treat a single handler argument as options and leaving the actual handler undefined, leading to runtime crashes when requests are received.

To fix this, check typeof optsOrHandler === "function" instead of relying on arguments.length.

Suggested change

	onRequest: (
	optsOrHandler:
	| https.HttpsOptions
	| ((req: https.Request, resp: express.Response) => void | Promise<void>),
	handler?: (req: https.Request, resp: express.Response) => void | Promise<void>
	) => {
	let opts: https.HttpsOptions;
	let userHandler: (req: https.Request, resp: express.Response) => void | Promise<void>;
	if (arguments.length === 1) {
	opts = {};
	userHandler = optsOrHandler as any;
	} else {
	opts = optsOrHandler as https.HttpsOptions;
	userHandler = handler!;
	}
	return https._onRequestWithOptions(userHandler, { ...this.options, ...opts } as any);
	},
	onRequest: (
	optsOrHandler:
	| https.HttpsOptions
	| ((req: https.Request, resp: express.Response) => void | Promise<void>),
	handler?: (req: https.Request, resp: express.Response) => void | Promise<void>
	) => {
	let opts: https.HttpsOptions;
	let userHandler: (req: https.Request, resp: express.Response) => void | Promise<void>;
	if (typeof optsOrHandler === "function") {
	opts = {};
	userHandler = optsOrHandler;
	} else {
	opts = optsOrHandler as https.HttpsOptions;
	userHandler = handler!;
	}
	return https._onRequestWithOptions(userHandler, { ...this.options, ...opts } as any);
	},

[gemini-code-assist]

For consistency and robustness, it is highly recommended to check typeof optsOrHandler === "function" instead of relying on arguments.length. This avoids potential issues if the function is refactored into an arrow function in the future and aligns with modern TypeScript practices.

Suggested change

	export function onRequest(
	handler: (req: Request, resp: express.Response) => void | Promise<void>
	optsOrHandler:
	| HttpsOptions
	| ((req: Request, resp: express.Response) => void | Promise<void>),
	handler?: (req: Request, resp: express.Response) => void | Promise<void>
	): HttpsFunction {
	return _onRequestWithOptions(handler, {});
	let opts: HttpsOptions;
	let userHandler: (req: Request, resp: express.Response) => void | Promise<void>;
	if (arguments.length === 1) {
	opts = {};
	userHandler = optsOrHandler as any;
	} else {
	opts = optsOrHandler as HttpsOptions;
	userHandler = handler!;
	}
	return _onRequestWithOptions(userHandler, opts as DeploymentOptions);
	}
	export function onRequest(
	optsOrHandler:
	| HttpsOptions
	| ((req: Request, resp: express.Response) => void | Promise<void>),
	handler?: (req: Request, resp: express.Response) => void | Promise<void>
	): HttpsFunction {
	let opts: HttpsOptions;
	let userHandler: (req: Request, resp: express.Response) => void | Promise<void>;
	if (typeof optsOrHandler === "function") {
	opts = {};
	userHandler = optsOrHandler;
	} else {
	opts = optsOrHandler as HttpsOptions;
	userHandler = handler!;
	}
	return _onRequestWithOptions(userHandler, opts as DeploymentOptions);
	}