914744 - [inspector] highlighter - "node is null" when navigating markup view during new page load

Status: RESOLVED DUPLICATE of bug 922125

(DevTools :: Inspector, defect)

Description

[Brian Grinstead [:bgrins]]

Steps to reproduce:
* Open devtools on a page
* Enter a slow loading page into the URL bar, like http://briangrinstead.com/files/sleepy.php
* While that is loading (takes 10 seconds), move around nodes in the markup view. 

I see the following error in my console:

TypeError: node is null: LocalHighlighter_updateInfobar@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/inspector/highlighter.js:569
EventEmitter_emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/shared/event-emitter.js:107
Selection.prototype.setNodeFront@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/inspector/selection.js:158
MT__navigate@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/markupview/markup-view.js:311
MT__KeyDown@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/markupview/markup-view.js:207

Comment 1

[Brian Grinstead [:bgrins]]

Attachment: 914744-selection.patch

This fixes this particular problem by not allowing a node to be selected if it is null, but I think this is only fixing a symptom of the problem (there are still other issues, like attempting to edit attributes).

We should probably either make the inspector fully work during the load of the new page (which it does in Firefox 23), or clear out the UI to prevent any changes.

Comment 2

[Simona Badau, Desktop QA, PTO 13-25aug]

Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:27.0) Gecko/20100101 Firefox/27.0
Build ID: 20130926030207

On the latest Nightly I'm also getting an error with the same message ("node is null") but with a different stack and the following steps to reproduce:

"PageStyleActor<.getApplied<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/styles.js:293actorProto/</handler@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:906DSC_onPacket@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js:1018@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js -> resource://gre/modules/devtools/server/transport.js:255@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js -> resource://gre/modules/devtools/DevToolsUtils.js:72"

Steps to reproduce:
1. Launch Nightly.
2. In the same tab navigate to 3 different websites.
3. Open the Inspector.
4. Click on the Back button two times.
--> the error with the message "node is null" can be seen in the Browser Console. 

Brian, could this have the same cause?

Comment 3

[Brian Grinstead [:bgrins]]

(In reply to Simona B [QA] from comment #2)
> Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:27.0) Gecko/20100101
> Firefox/27.0
> Build ID: 20130926030207
> 
> On the latest Nightly I'm also getting an error with the same message ("node
> is null") but with a different stack and the following steps to reproduce:
> 
> "PageStyleActor<.getApplied<@resource://gre/modules/commonjs/toolkit/loader.
> js ->
> resource://gre/modules/devtools/server/actors/styles.js:293actorProto/</
> handler@resource://gre/modules/commonjs/toolkit/loader.js ->
> resource://gre/modules/devtools/server/protocol.js:906DSC_onPacket@resource:/
> /gre/modules/devtools/dbg-server.jsm ->
> resource://gre/modules/devtools/server/main.js:1018@resource://gre/modules/
> devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js ->
> resource://gre/modules/devtools/server/transport.js:255@resource://gre/
> modules/devtools/dbg-server.jsm ->
> resource://gre/modules/devtools/server/main.js ->
> resource://gre/modules/devtools/DevToolsUtils.js:72"
> 
> Steps to reproduce:
> 1. Launch Nightly.
> 2. In the same tab navigate to 3 different websites.
> 3. Open the Inspector.
> 4. Click on the Back button two times.
> --> the error with the message "node is null" can be seen in the Browser
> Console. 
> 
> Brian, could this have the same cause?

I am able to see the issue using the STR as you describe.  I believe that this is one of many cases that pop up related to inspector navigation.  Bug 922125 should help here, and it sounds like Patrick's WIP patch for this bug also resolves this issue you reported.

Comment 4

[Patrick Brosset <:pbro>]

Now that bug 914744 landed, I'll test this one again soon.

Comment 5

[Patrick Brosset <:pbro>]

sorry I meant bug 922125 landed.