820740 - [rule view] exception since toolbox (TypeError: this._elementStyle is undefined)

Status: RESOLVED WORKSFORME

(DevTools :: Inspector, defect, P1)

Description

[Paul Rouget [:paul]]

TypeError: this._elementStyle is undefined: CssRuleView_nodeChanged@resource:///modules/devtools/CssRuleView.jsm:977
RVT_refresh@resource:///modules/devtools/StyleInspector.jsm:122
EventEmitter_emit@resource:///modules/devtools/EventEmitter.jsm:96
@resource:///modules/devtools/InspectorPanel.jsm:511

Happens when starting the inspector.

Comment 1

[Mike Ratcliffe [:miker] [:mratcliffe] [:mikeratcliffe]]

This could easily be the cause of other bugs.

Comment 2

[Mike Ratcliffe [:miker] [:mratcliffe] [:mikeratcliffe]]

I can't reproduce this.

Paul: Is this still broken for you?

Comment 3

[Paul Rouget [:paul]]

I'll reopen if I see it again.

Comment 4

[Paul Rouget [:paul]]

I see it again:

TypeError: this._elementStyle is null: CssRuleView_nodeChanged@resource:///modules/devtools/CssRuleView.jsm:977
RVT_refresh@resource:///modules/devtools/StyleInspector.jsm:123
EventEmitter_emit@resource:///modules/devtools/EventEmitter.jsm:100
@resource:///modules/devtools/InspectorPanel.jsm:577

Comment 5

[Paul Rouget [:paul]]

I breaks when we close the devtools or the browser tab.

It breaks because in CssRuleView.jsm:977, we use a property that has been destroyed.
It has been destroyed because the StyleInspector has been destroyed.

We still try to use the ruleview because of a layout-change event (StyleInspector.jsm#121).

But the weird thing is, before destroying the RuleView, we stop listening to the layout-change event. See StyleInspector.jsm#127.

Comment 6

[Mike Ratcliffe [:miker] [:mratcliffe] [:mikeratcliffe]]

Attachment: Patch v1

I still can't reproduce this so it is probably something a bit hinky with your architecture ... I am guessing that the computed view is destroyed and because it shares cssLogic with the rule view the object no longer exists.

Anyhow, here is the simplest of simple workarounds.

Comment 7

[Paul Rouget [:paul]]

(In reply to Michael Ratcliffe [:miker] [:mratcliffe] from comment #6)
> Created attachment 702819 [details] [diff] [review]
> Patch v1
> 
> I still can't reproduce this so it is probably something a bit hinky with
> your architecture ... I am guessing that the computed view is destroyed and
> because it shares cssLogic with the rule view the object no longer exists.
> 
> Anyhow, here is the simplest of simple workarounds.

I would really much like to understand first how we can get into this situation.

Comment 8

[Paul Rouget [:paul]]

I can't reproduce. But I tried. Hard.
Let's reopen if we ever see that again.