Web Inspector: Activity Viewer does not update on "clear all console messages"

[Tobias Reiss]

* SUMMARY
Clearing all console messages does not affect the Activity Viewer.

* STEPS TO REPRODUCE
1. Go to Console Tab
2. Type: console.error("error");
3. Activity Viewer shows one error
4. Clear log
5. Activity Viewer still shows one error

[Radar WebKit Bug Importer]

<rdar://problem/20834726>

[Nikita Vasilyev]

I was able to reproduce this bug by pressing the trash icon on the right top corner of the console.

Clearing the console by Control L works as expected.

[Tobias Reiss]

Looks like a regression that was introduced with
- http://trac.webkit.org/changeset/180721
- https://github.com/WebKit/webkit/commit/b4acedf6

[Tobias Reiss]

LogManager listens on "Console.messagesCleared" events from Backend. A typical stack of events looks like this on a page reload:

- load page that contains a console.log("test")
- "WebInspector.ConsoleObserver.messageAdded" // from Backend, prints "test"
- reload page
- "WebInspector.ConsoleObserver.messagesCleared" // from Backend
- "WebInspector.Frame.Event.MainResourceDidChange" // from ?, indicates "session start"
- "WebInspector.ConsoleObserver.messageAdded" // from Backend, prints "test"
- "WebInspector.ConsoleObserver.messagesCleared" // from Backend, why??

Conclusion
The former "messagesCleared" can be instrumented to clear on reload or not.
The latter "messagesCleared" breaks our logic and should be avoided.

[Tobias Reiss]

APIs that let you clear the Console:

- clear() and console.clear() are handled by Backend only [1]. WORKS
- Button and Context Menu are handled Frontend only [2] & [3]. DOES NOT WORK
- Clear/Keep on reload are handled by both. [1] & [4]. DOES NOT WORK
- Shortcuts are handled by both [5] & [1]. WORKS

WORKS means that the Console was cleared and Activity Viewer was updated correctly
DOES NOT WORK means that the Activity Viewer wasn't updated correctly.

I don't see a clear pattern here. Either the Backend should call "messagesCleared" more often and Frontend should get ride of some duplicated event handlers or the other way round. Right now the strategy looks inconsistent and order of event handlers is important.

[1] https://github.com/WebKit/webkit/blob/91ba8734ceadd8fd3b73942008358ef8a4a81715/Source/JavaScriptCore/inspector/agents/InspectorConsoleAgent.cpp#L107

[2] https://github.com/WebKit/webkit/blob/f647f216a7e9a781ba96bc823787fdf667f868ea/Source/WebInspectorUI/UserInterface/Views/LogContentView.js#L72

[3] https://github.com/WebKit/webkit/blob/f647f216a7e9a781ba96bc823787fdf667f868ea/Source/WebInspectorUI/UserInterface/Views/LogContentView.js#L344

[4] https://github.com/WebKit/webkit/blob/f647f216a7e9a781ba96bc823787fdf667f868ea/Source/WebInspectorUI/UserInterface/Views/LogContentView.js#L306

[5] https://github.com/WebKit/webkit/blob/846f78432c3b5b041177716350dc1335c8d45097/Source/WebInspectorUI/UserInterface/Controllers/JavaScriptLogViewController.js#L52-L53

[Tobias Reiss]

Created attachment 253917 [details]
patch

[Joseph Pecoraro]

Comment on attachment 253917 [details]
patch

View in context: https://bugs.webkit.org/attachment.cgi?id=253917&action=review

r=me! One step forward, good catch.

> Source/WebInspectorUI/UserInterface/Views/LogContentView.js:634
> +    // FIXME: https://bugs.webkit.org/show_bug.cgi?id=145466

I prefer writing bug links with their title. So:

    // FIXME: <https://webkit.org/b/145466> Web Inspector: Activity Viewer does not update on "Clear Log on reload"

[Tobias Reiss]

Created attachment 253922 [details]
patch

[Joseph Pecoraro]

Comment on attachment 253922 [details]
patch

r=me

[WebKit Commit Bot]

Comment on attachment 253922 [details]
patch

Clearing flags on attachment: 253922

Committed r185015: <http://trac.webkit.org/changeset/185015>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.