1773882 - setter & getter of an array are displayed as undefined

Status: RESOLVED FIXED

(DevTools :: Shared Components, defect, P3)

Description

[Krischna]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:101.0) Gecko/20100101 Firefox/101.0

Steps to reproduce:

1. Go into the console.
2. Execute this snippet:

var arr1=[],obj1={}
Object.defineProperty(arr1,0,{get: ()=>"Value"})
Object.defineProperty(obj1,"a",{get: ()=>"Value"})
var arr2=[],obj2={}
Object.defineProperty(arr2,0,{get: ()=>"Value", enumerable: true})
Object.defineProperty(obj2,"a",{get: ()=>"Value", enumerable: true})
console.log(arr1,obj1)
console.log(arr2,obj2)
console.log([...arr1],{...obj1})
console.log([...arr2],{...obj2})

Getters may also be replaced with setters. It has the same effect.

Actual results:

The getter in the arrays are displayed as undefined. Though they behave like getters.
Array [ undefined ] Object { … }
Array [ undefined ] Object { a: Getter }
Array [ "Value" ] Object { }
Array [ "Value" ] Object { a: "Value" }

Expected results:

The setter in the array should be displayed as such.
NodeJS, as an example, gets it right:
[ [Setter] ] {}
[ [Setter] ] { a: [Setter] }
[ undefined ] {}
[ undefined ] { a: undefined }

Comment 1

[Krischna]

Edit:
copypasted the wrong output from NodeJS and I can't seem to be able to edit the post.
Here the correct output from NodeJS:

[ [Getter] ] {}
[ [Getter] ] { a: [Getter] }
[ 'Value' ] {}
[ 'Value' ] { a: 'Value' }

Comment 2

[Tooru Fujisawa [:arai]]

The formatting is done in DevTools, grip-array.js and accessor.js

Comment 3

[Tooru Fujisawa [:arai]]

The undefined comes from the following:

https://searchfox.org/mozilla-central/rev/a8bdd0feeb7ae596a202333ee324a68153f9f4c4/devtools/server/actors/object/previewers.js#197-198,213-214,221-222,226,228-229

Array: [
  function({ obj, hooks }, grip) {
...
    for (let i = 0; i < length; ++i) {
      if (raw && !isWorker) {
...
        const desc = Object.getOwnPropertyDescriptor(Cu.waiveXrays(raw), i);
        if (desc && !desc.get && !desc.set) {
...
        } else if (!desc) {
...
        } else {
          items.push(hooks.createValueGrip(undefined));

Comment 4

[Tooru Fujisawa [:arai]]

Attachment: Bug 1773882 - Show getter/setter in array element. r?nchevobbe!

Comment 5

[Tooru Fujisawa [:arai]]

Attachment: Bug 1773882 - Part 2: Add more testcase. r?nchevobbe!

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0646b8bb3ec5
Show getter/setter in array element. r=nchevobbe
https://hg.mozilla.org/integration/autoland/rev/e033ff580f53
Part 2: Add more testcase. r=nchevobbe

Comment 7

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/0646b8bb3ec5
https://hg.mozilla.org/mozilla-central/rev/e033ff580f53