802394 - document.body is null in aboutHome.js

Status: RESOLVED FIXED

(Firefox :: General, defect)

Description

[Jared Wein [:jaws] (please needinfo? me)]

Timestamp: 10/16/2012 3:29:58 PM
Error: TypeError: document.body is null
Source File: chrome://browser/content/abouthome/aboutHome.js
Line: 236

where line 236 is:
>   } else if (document.body.hasAttribute("narrow")) {

Comment 1

[Jared Wein [:jaws] (please needinfo? me)]

STR:
Have about:home as the homepage for the browser
Open the Error Console
Open a New Window
Look at Error Console

Comment 2

[Jared Wein [:jaws] (please needinfo? me)]

Attachment: Patch

By placing some alert()'s in the code, I found that new windows are getting the 'resize' event before 'load', and that is what is causing document.body to be null.

Comment 3

[Dão Gottwald [:dao]]

Comment on attachment 672077 [details] [diff] [review]
Patch

> function fitToWidth() {
>+  if (!gPageLoaded)

Does |if (document.readyState != "complete")| work here?

Comment 4

[Jared Wein [:jaws] (please needinfo? me)]

Attachment: Patch v2

Yeah, that's a better approach and works well.

Comment 5

[Jared Wein [:jaws] (please needinfo? me)]

Updated STR,

(In reply to Jared Wein [:jaws] from comment #1)
> STR:
> Have about:home as the homepage for the browser
Open a sidebar.
> Open the Error Console
> Open a New Window
> Look at Error Console

The open sidebar causes the resize before the document has loaded.

Comment 6

[Dão Gottwald [:dao]]

(In reply to Jared Wein [:jaws] from comment #5)
> The open sidebar causes the resize before the document has loaded.

Works for me, although this isn't too surprising if this is a race condition.

Do you get the error in Firefox 16, aurora, beta, nightly or only in a custom build?

Comment 7

[Jared Wein [:jaws] (please needinfo? me)]

I can reproduce in a regular Nightly build with the social sidebar open.

Comment 8

[Dão Gottwald [:dao]]

What code opens the social side bar?

Comment 9

[Dão Gottwald [:dao]]

Comment on attachment 672121 [details] [diff] [review]
Patch v2

Anyway... I think a better fix would be to move window.addEventListener("resize", fitToWidth); inside the load listener.

Comment 10

[Jared Wein [:jaws] (please needinfo? me)]

Attachment: Patch v2.1

Comment 11

[Jared Wein [:jaws] (please needinfo? me)]

To show the social sidebar, go to about:config and set social.active=true and social.enabled=true. You can then use the menu from the toolbar button to toggle the sidebar visibility.

Comment 12

[Frank Yan (:fryn)]

(In reply to Jared Wein [:jaws] from comment #11)
I think Dão was asking for the line(s) of code that perform that operation.

Comment 13

[Jared Wein [:jaws] (please needinfo? me)]

This is the call stack,
SocialSidebar_updateSidebar@chrome://browser/content/browser.js:4644
SocialSidebar_init@chrome://browser/content/browser.js:4605
SocialUI_providerReady@chrome://browser/content/browser.js:3977
chrome://browser/content/browser.js:4646

note that since browser.js was split into multiple files, much of this code will actually be found in browser-social.js.

Comment 14

[Jared Wein [:jaws] (please needinfo? me)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/142ee4ac9b30

Comment 15

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/142ee4ac9b30