this._getSession is not a function while use HttpsProxyAgent

[WhoisUnknown]

Hi, I encounter a bug when I use proxy for requests

TypeError: this._getSession is not a function
    at HttpsProxyAgent.createConnection (node:https:140:26)
    at MockHttpSocket.passthrough (example/node_modules/@mswjs/interceptors/src/interceptors/ClientRequest/MockHttpSocket.ts:160:25)
    at _ClientRequestInterceptor.onRequest (example/node_modules/@mswjs/interceptors/src/interceptors/ClientRequest/index.ts:151:21)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)

Example repo https://github.com/WhoisUnknown/example-interseptor

I used version 0.36.10

[fionawhim]

Seeing this as well, with 0.37.1 and Node v20.12.0. My use case is MSW running in a Vitest test, and trying to access (unmocked) HTTPS endpoints.

I think the code in the Node repo is here: https://github.com/nodejs/node/blob/v20.x/lib/https.js#L163

Possibly a situation in the way that the createConnection method is used here? It gets bound to something without a _getSession method, but an _agentKey is still being passed into options?

[sebws]

interceptors/src/interceptors/ClientRequest/agents.ts

Lines 67 to 82 in c338da8

	public createConnection(options: any, callback: any) {
	const createConnection =
	(this.customAgent instanceof https.Agent &&
	this.customAgent.createConnection) ||
	super.createConnection
	const socket = new MockHttpSocket({
	connectionOptions: options,
	createConnection: createConnection.bind(
	this.customAgent || this,
	options,
	callback
	),
	onRequest: this.onRequest.bind(this),
	onResponse: this.onResponse.bind(this),
	})

Looks like what happens is that this.customAgent is there, but it isn't an instance of https.Agent, so createConnection is taken from super.createConnection. Then when we go to bind at L75-L79, it binds super.createConnection to this.customAgent. No good!

Given that createConnection does exist on the HttpsProxyAgent (this.customAgent), I think it shouldn't be that super.createConnection is now bound to this instead of this.customAgent, instead that the check isn't if this.customAgent is an instance of https.Agent but something else?

I'm not sure of the intent here. Hopefully somebody who knows better what's intended to happen here, might just be @kettanaito