1538774 - Warning: Each child in an array or iterator should have a unique "key" prop.

Status: RESOLVED FIXED

(DevTools :: Debugger, defect)

Description

[Jan Honza Odvarko [:Honza] (always need-info? me)]

I am seeing the following warning in the Browser Console:

Warning: Each child in an array or iterator should have a unique "key" prop.

Check the render method of SourcesTree. See https://fb.me/react-warning-keys for more information.
in div (created by SourcesTree)
in SourcesTree (created by Connect(SourcesTree))
in Connect(SourcesTree) (created by PrimaryPanes)
in div (created by PrimaryPanes)

printWarning resource://devtools/client/shared/vendor/react-dev.js:369
warning resource://devtools/client/shared/vendor/react-dev.js:393
validateExplicitKey resource://devtools/client/shared/vendor/react-dev.js:1555
validateChildKeys resource://devtools/client/shared/vendor/react-dev.js:1577
createElementWithValidation resource://devtools/client/shared/vendor/react-dev.js:1708
renderPane resource://devtools/client/debugger/new/src/components/PrimaryPanes/SourcesTree.js:168
render resource://devtools/client/debugger/new/src/components/PrimaryPanes/SourcesTree.js:220

--

STR

1. Start a worker with BP in it
2. The worker execution should stop immediately
3. New entry should be added to the Sources tree

Honza

Comment 1

[Jan Honza Odvarko [:Honza] (always need-info? me)]

Online example:

STR:

1. Load http://janodvarko.cz/tests/bugzilla/1538774/
2. Click Start Worker! on the page
3. Create BP on line 15
4. Close entire tab and open again
5. Click Start Worker! on the page
6. The worker should start and pause immediately
7. Open Browser Console, see the warning -> BUG

---

Note that there is also
Warning: React does not recognize the clasName prop on a DOM element. If you intentionally want it to appear in the DOM as a custom attribute, spell it as lowercase clasname instead. If you accidentally passed it from a parent component, remove it

Honza

Comment 2

[David Walsh :davidwalsh]

Attachment: Bug 1538774 - Part 1 - Fix clasName bug r=jlast

Fixes a typo for className. Only part 1, doesn't address actual issue.

Comment 3

[David Walsh :davidwalsh]

I started a patch for the two issues presented but I could't reproduce with Honza's instructions. Additionally, I looked at the line numbers and neither of them would trigger this type of issue.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/409294d60d61
Part 1 - Fix clasName bug r=jlast

Comment 5

[Oana Pop-Rus]

https://hg.mozilla.org/mozilla-central/rev/409294d60d61