Bug 173425 – Uncaught Exception: TypeError: null is not an object (evaluating 'this.contentBrowser.contentViewForRepresentedObject')

• Status: RESOLVED
• Resolution: FIXED
• Component: Web Inspector

[Joseph Pecoraro]

Summary:
Uncaught Exception switching between tabs for the first time.

Steps to Reproduce:
1. Inspect <https://msaboff.github.io/RallyTracker/index.html>
2. Show Storage Tab
3. Select the Application Cache (index.html)
4. Select the Debugger Tab
5. Close Inspector
6. Open Inspector (Develop > Show Web Inspector)
  => Should open to the Debugger tab
7. Select the Storage Tab
  => Uncaught Exception

Uncaught Exceptions:
 - TypeError: null is not an object (evaluating 'this.contentBrowser.contentViewForRepresentedObject') (at NavigationSidebarPanel.js:191:50)
    showDefaultContentViewForTreeElement @ NavigationSidebarPanel.js:191:50
    _checkElementsForPendingViewStateCookie @ NavigationSidebarPanel.js:709:79
    restoreStateFromCookie @ NavigationSidebarPanel.js:237:53
    restoreStateFromCookie @ TabContentView.js:156:63
    shown @ TabContentView.js:135:40
    shown @ ContentBrowserTabContentView.js:95:20
    prepareToShow @ BackForwardEntry.js:86:35
    _showEntry @ ContentViewContainer.js:445:28
    showBackForwardEntryForIndex @ ContentViewContainer.js:162:28
    showContentView @ ContentViewContainer.js:138:42
    _tabBarItemSelected @ TabBrowser.js:239:55
    dispatch @ Object.js:170:30
    dispatchEventToListeners @ Object.js:177:17
    selectedTabBarItem @ TabBar.js:376:38
    _handleMouseDown @ TabBar.js:569:13
    _handleMouseDown @ [native code]

[Joseph Pecoraro]

<rdar://problem/32744172>

[Joseph Pecoraro]

I can provide a simple solution to avoid the uncaught exception (and therefore the broken tab appearance that results) however it appears tab state restoration is not working as expected (selecting something in the sidebar + loading its content view). I think this is a regression from lazy sidebar initialization.

[Joseph Pecoraro]

Created attachment 313001 [details]
[PATCH] Proposed Fix

[Joseph Pecoraro]

> I think this is a regression from lazy sidebar initialization.

I don't think this is a regression from lazy sidebar initialization. But it is certainly a mixture of issues. I made restoration work slightly better in both the Debugger and Storage tabs.

[Devin Rousso]

Comment on attachment 313001 [details]
[PATCH] Proposed Fix

r=me

View in context: https://bugs.webkit.org/attachment.cgi?id=313001&action=review

> Source/WebInspectorUI/ChangeLog:16
> +        By default select a script/resource content view instead of nothing.

This sentence is awkward to me.

Always select a script/resource content view instead of nothing.

> Source/WebInspectorUI/UserInterface/Views/ContentBrowserTabContentView.js:98
>          if (this.navigationSidebarPanel) {
>              if (!this.navigationSidebarPanel.contentBrowser)
>                  this.navigationSidebarPanel.contentBrowser = this._contentBrowser;
> +        }

You can squash the two if statements:

if (this.navigationSidebarPanel && !this.navigationSidebarPanel.contentBrowser)
    this.navigationSidebarPanel.contentBrowser = this._contentBrowser;

> Source/WebInspectorUI/UserInterface/Views/ContentBrowserTabContentView.js:107
> +        if (this.navigationSidebarPanel) {
>              if (!this._contentBrowser.currentContentView)
>                  this.navigationSidebarPanel.showDefaultContentView();
>          }

Ditto:

if (this.navigationSidebarPanel && !this._contentBrowser.currentContentView)
    this.navigationSidebarPanel.showDefaultContentView();

[Joseph Pecoraro]

Created attachment 313002 [details]
[PATCH] For Landing

[WebKit Commit Bot]

Comment on attachment 313002 [details]
[PATCH] For Landing

Clearing flags on attachment: 313002

Committed r218356: <http://trac.webkit.org/changeset/218356>