errors: strange position name in error stack

[vsemozhetbyt]

• Version: 8.5.0, master (9.0.0 2017 09 12)
• Platform: Windows 7 x64
• Subsystem: errors

Compare these 3 async IIFEs and their error stacks (different code lines and corresponded stack position names are marked by // NB string):

'use strict';

function promiseFunc(arg) {
  return new Promise(function promiseHandlers(resolve, reject) {
    if (arg) resolve(`Got ${arg}`);
    else reject(new Error(`Got ${arg}`));
  });
}

(async function asyncFunc() {                // NB
  try {
    const result = await promiseFunc(true);
    console.log(`Result: ${result}`);

    await promiseFunc(false);
    console.log('This is not logged.');
  } catch (err) {
    console.error(err);
  }
}());

(async function () {                         // NB
  try {
    const result = await promiseFunc(true);
    console.log(`Result: ${result}`);

    await promiseFunc(false);
    console.log('This is not logged.');
  } catch (err) {
    console.error(err);
  }
}());

(async () => {                               // NB
  try {
    const result = await promiseFunc(true);
    console.log(`Result: ${result}`);

    await promiseFunc(false);
    console.log('This is not logged.');
  } catch (err) {
    console.error(err);
  }
})();

Result: Got true
Result: Got true
Result: Got true
Error: Got false
    at promiseHandlers (e:\DOC\prg\js\node\-test\test.js:6:17)
    at Promise (<anonymous>)
    at promiseFunc (e:\DOC\prg\js\node\-test\test.js:4:10)
    at asyncFunc (e:\DOC\prg\js\node\-test\test.js:15:11)                // NB
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
    at Function.Module.runMain (module.js:667:11)
    at startup (bootstrap_node.js:201:16)
    at bootstrap_node.js:626:3
Error: Got false
    at promiseHandlers (e:\DOC\prg\js\node\-test\test.js:6:17)
    at Promise (<anonymous>)
    at promiseFunc (e:\DOC\prg\js\node\-test\test.js:4:10)
    at e:\DOC\prg\js\node\-test\test.js:27:11                            // NB
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
    at Function.Module.runMain (module.js:667:11)
    at startup (bootstrap_node.js:201:16)
    at bootstrap_node.js:626:3
Error: Got false
    at promiseHandlers (e:\DOC\prg\js\node\-test\test.js:6:17)
    at Promise (<anonymous>)
    at promiseFunc (e:\DOC\prg\js\node\-test\test.js:4:10)
    at __dirname (e:\DOC\prg\js\node\-test\test.js:39:11)                // NB
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
    at Function.Module.runMain (module.js:667:11)
    at startup (bootstrap_node.js:201:16)
    at bootstrap_node.js:626:3

Is __dirname position name in the last stack intended?

[targos]

I think it's a bug. Here is the output with d8:

Result: Got true
Result: Got true
Result: Got true
Error: Got false
    at promiseHandlers (/home/mzasso/test/stack.js:6:17)
    at Promise (<anonymous>)
    at promiseFunc (/home/mzasso/test/stack.js:4:10)
    at asyncFunc (/home/mzasso/test/stack.js:15:11)
    at <anonymous>
Error: Got false
    at promiseHandlers (/home/mzasso/test/stack.js:6:17)
    at Promise (<anonymous>)
    at promiseFunc (/home/mzasso/test/stack.js:4:10)
    at /home/mzasso/test/stack.js:27:11
    at <anonymous>
Error: Got false
    at promiseHandlers (/home/mzasso/test/stack.js:6:17)
    at Promise (<anonymous>)
    at promiseFunc (/home/mzasso/test/stack.js:4:10)
    at /home/mzasso/test/stack.js:39:11
    at <anonymous>

[targos]

OK this is a V8 bug. Repro for d8:

(function (param1) {

  (async () => {
    try {
      await Promise.reject(new Error('boom'));
    } catch (err) {
      console.error(err.stack);
    }
  })();

})();

Error: boom
    at param1 (problem.js:5:28)
    at problem.js:9:5
    at problem.js:11:3

/cc @nodejs/v8

[targos]

It does not have to be an async function btw:

(function (param1) {

  (() => {
    try {
      throw new Error('boom');
    } catch (err) {
      console.error(err.stack);
    }
  })();

})();

Error: boom
    at param1 (problem.js:5:13)
    at problem.js:9:5
    at problem.js:11:3

[vsemozhetbyt]

@targos So is the output in the OP somehow connected with module wrapper last argument?

[targos]

Exactly. The bug is that the stack trace uses the name of the last argument of the outer function in place of the name of the function, when that function is a arrow function.

[vsemozhetbyt]

@targos Do you plan to post upstream or should I try to?

[targos]

You're welcome to do it: https://bugs.chromium.org/p/v8/issues/entry?template=Node.js+upstream+bug

[vsemozhetbyt]

Hopefully done. Should we close this issue or should it remain open till upstream fix?

[targos]

Let's keep it open until we know if the fix can be backported

[vsemozhetbyt]

FWIW, the output from maintained branches (Node.js v6 with v8 5.1 seems concerned in a different way):

'use strict';

(function (param1) {

  (() => {
    try {
      throw new Error('boom');
    } catch (err) {
      console.error(err.stack);
    }
  })();

})();

> node.4.8.4.v8-4.5.exe test.js
Error: boom
    at e:\DOC\prg\js\node\-test\test.js:7:13
    at e:\DOC\prg\js\node\-test\test.js:11:5
    at Object.<anonymous> (e:\DOC\prg\js\node\-test\test.js:13:3)
    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.6.11.3.v8-5.1.exe test.js
Error: boom
    at err (e:\DOC\prg\js\node\-test\test.js:7:13)
    at e:\DOC\prg\js\node\-test\test.js:11:5
    at Object.<anonymous> (e:\DOC\prg\js\node\-test\test.js:13:3)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Module.runMain (module.js:604:10)
    at run (bootstrap_node.js:389:7)

> node.8.5.0.v8-6.0.exe test.js
Error: boom
    at param1 (e:\DOC\prg\js\node\-test\test.js:7:13)
    at e:\DOC\prg\js\node\-test\test.js:11:5
    at Object.<anonymous> (e:\DOC\prg\js\node\-test\test.js:13:3)
    at Module._compile (module.js:624:30)
    at Object.Module._extensions..js (module.js:635:10)
    at Module.load (module.js:545:32)
    at tryModuleLoad (module.js:508:12)
    at Function.Module._load (module.js:500:3)
    at Function.Module.runMain (module.js:665:10)
    at startup (bootstrap_node.js:201:16)