vm: Function declarations should use [[Define]] instead of [[Set]] on the global object

• Version: v13.8.0
• Platform: All; tested on Travis CI (Ubuntu 16.04.6 LTS)
• Subsystem: vm

What steps will reproduce the bug?

const vm = require("vm");

let impl = { status: "" };
let ctx = vm.createContext();
Object.defineProperty(ctx, "status", {
	configurable: true,
	enumerable: true,
	get() {
		return impl.status;
	},
	set(v) {
		impl.status = `${v}`;
	},
});

// https://github.com/web-platform-tests/wpt/blob/master/xhr/status-async.htm
vm.runInContext(`
function statusRequest(...args) {
	console.log(args.map(JSON.stringify).join("\t"));
}
function status(code, text, content, type) {
	statusRequest("GET", code, text, content, type);
	statusRequest("HEAD", code, text, content, type);
	statusRequest("CHICKEN", code, text, content, type);
}
status(204, "UNICORNSWIN", "", "")
status(401, "OH HELLO", "Not today.", "")
status(402, "FIVE BUCKS", "<x>402<\/x>", "text/xml")
status(402, "FREE", "Nice!", "text/doesnotmatter")
status(402, "402 TEH AWESOME", "", "")
status(502, "YO", "", "")
status(502, "lowercase", "SWEET POTATO", "text/plain")
status(503, "HOUSTON WE HAVE A", "503", "text/plain")
status(699, "WAY OUTTA RANGE", "699", "text/plain")
`, ctx);

How often does it reproduce? Is there a required condition?

Always.

What is the expected behavior?

The functions get defined using [[DefineOwnProperty]] as specified in ECMA‑262 § 8.1.1.4.18 CreateGlobalFunctionBinding.

"GET"
	
204
	
"UNICORNSWIN"
	
""
	
""
"HEAD"
	
204
	
"UNICORNSWIN"
	
""
	
""
"CHICKEN"
	
204
	
"UNICORNSWIN"
	
""
	
""
"GET"
	
401
	
"OH HELLO"
	
"Not today."
	
""
"HEAD"
	
401
	
"OH HELLO"
	
"Not today."
	
""
"CHICKEN"
	
401
	
"OH HELLO"
	
"Not today."
	
""
"GET"
	
402
	
"FIVE BUCKS"
	
"402"
	
"text/xml"
"HEAD"
	
402
	
"FIVE BUCKS"
	
"402"
	
"text/xml"
"CHICKEN"
	
402
	
"FIVE BUCKS"
	
"402"
	
"text/xml"
"GET"
	
402
	
"FREE"
	
"Nice!"
	
"text/doesnotmatter"
"HEAD"
	
402
	
"FREE"
	
"Nice!"
	
"text/doesnotmatter"
"CHICKEN"
	
402
	
"FREE"
	
"Nice!"
	
"text/doesnotmatter"
"GET"
	
402
	
"402 TEH AWESOME"
	
""
	
""
"HEAD"
	
402
	
"402 TEH AWESOME"
	
""
	
""
"CHICKEN"
	
402
	
"402 TEH AWESOME"
	
""
	
""
"GET"
	
502
	
"YO"
	
""
	
""
"HEAD"
	
502
	
"YO"
	
""
	
""
"CHICKEN"
	
502
	
"YO"
	
""
	
""
"GET"
	
502
	
"lowercase"
	
"SWEET POTATO"
	
"text/plain"
"HEAD"
	
502
	
"lowercase"
	
"SWEET POTATO"
	
"text/plain"
"CHICKEN"
	
502
	
"lowercase"
	
"SWEET POTATO"
	
"text/plain"
"GET"
	
503
	
"HOUSTON WE HAVE A"
	
"503"
	
"text/plain"
"HEAD"
	
503
	
"HOUSTON WE HAVE A"
	
"503"
	
"text/plain"
"CHICKEN"
	
503
	
"HOUSTON WE HAVE A"
	
"503"
	
"text/plain"
"GET"
	
699
	
"WAY OUTTA RANGE"
	
"699"
	
"text/plain"
"HEAD"
	
699
	
"WAY OUTTA RANGE"
	
"699"
	
"text/plain"
"CHICKEN"
	
699
	
"WAY OUTTA RANGE"
	
"699"
	
"text/plain"

What do you see instead?

evalmachine.<anonymous>:10
status(204, "UNICORNSWIN", "", "")
^

Uncaught TypeError: status is not a function
    at evalmachine.<anonymous>:10:1
    at Script.runInContext (vm.js:131:20)
    at Object.runInContext (vm.js:295:6)
    at repl:1:4
    at Script.runInThisContext (vm.js:120:20)
    at REPLServer.defaultEval (repl.js:432:29)
    at bound (domain.js:429:14)
    at REPLServer.runBound [as eval] (domain.js:442:12)
    at REPLServer.onLine (repl.js:759:10)
    at REPLServer.emit (events.js:333:22)

Additional information

Discovered in: https://github.com/jsdom/jsdom/pull/2835#discussion_r379706437

See also

• https://github.com/nodejs/node/issues/38918
• https://issues.chromium.org/issues/42202495

スタックトレースに示された vm.js の箇所から開始し、提供された vm.runInContext の再現コードを実行します。関数宣言がコンテキストのグローバルオブジェクトにインストールされる仕組みを追跡し、その後、関数がアクセサーをトリガーしなくなっていることと、期待されるログ出力が生成されることを確認します。