nodejs / nodejs/node

Missing import trace from error stack when loading a module throws an error

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#46,992 30 commenti 11 reazioni 0 assegnatari Vedi su GitHub

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esm feature request
Lingua principale
JavaScript
Stelle
122k
Fork
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Merge medio
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PR unite (30g)
283

Descrizione

Version

v16.16.0

Platform

Linux 5.4.0-139-generic #156-Ubuntu SM x86_64 GNU/Linux

Subsystem

modules

What steps will reproduce the bug?

Consider:

// foo.mjs
import './bar.mjs';
// bar.mjs
throw new Error('bar failed');

Run node foo.mjs.

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

Always.

What is the expected behavior?

The stack trace from the error should include a reference to foo.mjs line 1 showing where bar was imported from.

What do you see instead?
file:///.../bar.mjs:1
throw new Error('bar failed');
      ^

Error: bar failed
    at file:///.../bar.mjs:1:7
    at ModuleJob.run (node:internal/modules/esm/module_job:198:25)
    at async Promise.all (index 0)
    at async ESMLoader.import (node:internal/modules/esm/loader:385:24)
    at async loadESM (node:internal/process/esm_loader:88:5)
    at async handleMainPromise (node:internal/modules/run_main:61:12)

Note that the stack trace does not mention foo anywhere. This is not helpful, especially if the error is specifically about how and when bar is imported. For example, it might be a singleton and you're mistakenly creating a duplicate by loading it from both import and require, or it might need something else to be set up on the global first and you're loading it in the wrong order.

The above stack is from node 16. Node 18 produces a shorter but similarly lacking stack:

file:///.../bar.mjs:1
throw new Error('bar failed');
      ^

Error: bar failed
    at file:///.../bar.mjs:1:7
    at ModuleJob.run (node:internal/modules/esm/module_job:194:25)
Additional information

I am aware that import() and top-level await complicates this, since modules may be effectively loading in parallel (asynchronously behind the scenes). However, it is absolutely essential that this information is made available somehow.

If the output ends up being a list of all modules trying to load the offending module then great, as long as this list is in the order the imports were encountered then that should allow debugging this kind of thing.

At the moment when this occurs it's simply impossible to debug. Since import gets hoisted by the language you can't even add console.log statements around the place to trace what's happening like you can with require. Literally the only option to debug this is to comment out all the imports and re-enable one-by-one (recursively) until you locate the problem. And in practice this inevitably breaks something else, so it's completely unworkable.

Guida per i contributori

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Come iniziare

  1. Leggi tutta la issue e poi la guida ai contributi del progetto.
  2. Commenta sulla issue per dire che te ne occupi tu — evita che due persone facciano lo stesso lavoro.
  3. Fai un fork del repository e lavora su un branch.
  4. Apri una pull request che faccia riferimento al numero della issue.

Direzione di ricerca

Inizia riproducendo il problema con i moduli foo.mjs e bar.mjs usando node foo.mjs, quindi esamina il sottosistema dei moduli coinvolto nel caricamento di ESM. Traccia il modo in cui gli errori si propagano attraverso il percorso di importazione e caricamento dei moduli. Il lavoro è completato quando le informazioni risultanti dello stack identificano la riga 1 di foo.mjs, tenendo conto dei casi di importazione asincrona descritti.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Valutazione

Stack tecnologico
javascript
Ambito
backend
Tipo di issue
Bug
Difficoltà
4/5
Tempo stimato
3-5 giorni
Stato di attività
Tranquilla
Chiarezza
Abbastanza chiara
Idoneità per principianti
45/100

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