Duplicated stack trace

[advanceddeveloper]

• Version: 9.11.1
• Platform: windo 10
• Subsystem: stack trace?

Hello. Im working on a project and experiencing weird bug. Our stack trace is duplicated, I mean it displays two times functions that I called only once. My project is very big, so we did our best to reduce it as much as we could. Here is minimal repro

"use strict";

var util = require("util");

var v1 = "example";
var v2 = [];
var v3 = null;

var closure = getClosure(v3);
var value = closure("func")(v1);
console.log(v2.length);

function getClosure(v1) {
  if(v1 === "example")
    return v1;

  try {
    v1 = `${v1.length}`;
  } catch(v2) {
    v1 = util.inspect(v2);
    v3 = v2;
  }

  var f = v2 => {
    if(v2 === "func") return f.func(v2);
    return f.obj[v1];
  };
  f.func = a => f(a && v3);
  f.obj =  {
    [v1](v2) {
      return v2.obj.length;
    }
  };

  return f;
}

It reproduces 100% of times. we tried to remove some parts of the code, but then it dont rreproduces issue.
I know this code throws error, this is because of obj is not a defined property, so it is undefined and therefore cannot read length of property obj, but it is not reason to print duplicated stack trace

My apologies for bad formatting, not very familiar with github markdown

[AyushG3112]

Can you post what stack trace you get?

[vsemozhetbyt]

This is what I get from all actual versions.

Stacks:

> node.04.09.0.v8-4.5.exe test.js
test.js:31
      return v2.obj.length;
                   ^

TypeError: Cannot read property 'length' of undefined
    at f.func.f.obj.v2 (test.js:31:20)
    at Object.<anonymous> (test.js:10:28)
    at Module._compile (module.js:409:26)
    at Object.Module._extensions..js (module.js:416:10)
    at Module.load (module.js:343:32)
    at Function.Module._load (module.js:300:12)
    at Function.Module.runMain (module.js:441:10)
    at startup (node.js:140:18)
    at node.js:1043:3

> node.06.14.0.v8-5.1.exe test.js
test.js:31
      return v2.obj.length;
                   ^

TypeError: Cannot read property 'length' of undefined
    at TypeError: Cannot read property 'length' of null
    at getClosure (test.js:18:15)
    at Object.<anonymous> (test.js:9:15)
    at Module._compile (module.js:577:32)
    at Object.Module._extensions..js (module.js:586:10)
    at Module.load (module.js:494:32)
    at tryModuleLoad (module.js:453:12)
    at Function.Module._load (module.js:445:3)
    at Module.runMain (module.js:611:10)
    at run (bootstrap_node.js:387:7)
    at startup (bootstrap_node.js:153:9) (test.js:31:20)
    at Object.<anonymous> (test.js:10:28)
    at Module._compile (module.js:577:32)
    at Object.Module._extensions..js (module.js:586:10)
    at Module.load (module.js:494:32)
    at tryModuleLoad (module.js:453:12)
    at Function.Module._load (module.js:445:3)
    at Module.runMain (module.js:611:10)
    at run (bootstrap_node.js:387:7)
    at startup (bootstrap_node.js:153:9)

> node.08.11.0.v8-6.2.exe test.js
test.js:31
      return v2.obj.length;
                    ^

TypeError: Cannot read property 'length' of undefined
    at TypeError: Cannot read property 'length' of null
    at getClosure (test.js:18:16)
    at Object.<anonymous> (test.js:9:15)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
    at tryModuleLoad (module.js:505:12)
    at Function.Module._load (module.js:497:3)
    at Function.Module.runMain (module.js:693:10)
    at startup (bootstrap_node.js:188:16)
    at bootstrap_node.js:609:3 (test.js:31:21)
    at Object.<anonymous> (test.js:10:28)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
    at tryModuleLoad (module.js:505:12)
    at Function.Module._load (module.js:497:3)
    at Function.Module.runMain (module.js:693:10)
    at startup (bootstrap_node.js:188:16)
    at bootstrap_node.js:609:3

> node.09.11.1.v8-6.2.exe test.js
test.js:31
      return v2.obj.length;
                    ^

TypeError: Cannot read property 'length' of undefined
    at TypeError: Cannot read property 'length' of null
    at getClosure (test.js:18:16)
    at Object.<anonymous> (test.js:9:15)
    at Module._compile (internal/modules/cjs/loader.js:654:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:665:10)
    at Module.load (internal/modules/cjs/loader.js:566:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:506:12)
    at Function.Module._load (internal/modules/cjs/loader.js:498:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:695:10)
    at startup (internal/bootstrap/node.js:201:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:516:3) (test.js:31:21)
    at Object.<anonymous> (test.js:10:28)
    at Module._compile (internal/modules/cjs/loader.js:654:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:665:10)
    at Module.load (internal/modules/cjs/loader.js:566:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:506:12)
    at Function.Module._load (internal/modules/cjs/loader.js:498:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:695:10)
    at startup (internal/bootstrap/node.js:201:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:516:3)

> node.10.0.0.v8-6.6.2018-04-12.nightly.exe test.js
test.js:31
      return v2.obj.length;
                    ^

TypeError: Cannot read property 'length' of undefined
    at TypeError: Cannot read property 'length' of null
    at getClosure (test.js:18:16)
    at Object.<anonymous> (test.js:9:15)
    at Module._compile (internal/modules/cjs/loader.js:678:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:689:10)
    at Module.load (internal/modules/cjs/loader.js:589:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:528:12)
    at Function.Module._load (internal/modules/cjs/loader.js:520:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:719:10)
    at startup (internal/bootstrap/node.js:228:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:575:3) (test.js:31:21)
    at Object.<anonymous> (test.js:10:28)
    at Module._compile (internal/modules/cjs/loader.js:678:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:689:10)
    at Module.load (internal/modules/cjs/loader.js:589:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:528:12)
    at Function.Module._load (internal/modules/cjs/loader.js:520:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:719:10)
    at startup (internal/bootstrap/node.js:228:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:575:3)

> node.10.0.0.v8-6.7.2018-04-11.v8-canary.exe test.js
test.js:31
      return v2.obj.length;
                    ^

TypeError: Cannot read property 'length' of undefined
    at TypeError: Cannot read property 'length' of null
    at getClosure (test.js:18:16)
    at Object.<anonymous> (test.js:9:15)
    at Module._compile (internal/modules/cjs/loader.js:678:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:689:10)
    at Module.load (internal/modules/cjs/loader.js:589:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:528:12)
    at Function.Module._load (internal/modules/cjs/loader.js:520:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:719:10)
    at startup (internal/bootstrap/node.js:228:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:575:3) (test.js:31:21)
    at Object.<anonymous> (test.js:10:28)
    at Module._compile (internal/modules/cjs/loader.js:678:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:689:10)
    at Module.load (internal/modules/cjs/loader.js:589:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:528:12)
    at Function.Module._load (internal/modules/cjs/loader.js:520:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:719:10)
    at startup (internal/bootstrap/node.js:228:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:575:3)

[apapirovski]

It's basically calling toString on your v2 while printing the stack trace which is now a string of the full error due to util.inspect. That's why eventually you get a line that goes something like:

at bootstrapNodeJSCore (internal/bootstrap/node.js:516:3) (/Users/apapirovski/Web/nodejs/test.js:32:21)

This would be better suited to https://github.com/nodejs/help/issues since there's no bugs or issues with Node.js core.

[bnoordhuis]

Answered, closing.