[Webkit-unassigned] [Bug 129896] New: XMLHttpRequest calls make page unresponsive beyond recovery

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=129896

           Summary: XMLHttpRequest calls make page unresponsive beyond
                    recovery
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: Unspecified
               URL: http://ldz-test4.medyk.org
        OS/Version: Unspecified
            Status: NEW
          Severity: Critical
          Priority: P5
         Component: HTML DOM
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: medikoo+webkit.org at medikoo.com


I work with single-page application in which following happens when user tries to login: XMLHttpRequest is send, and on success at same time data form server is send via Server Sent Events channel. After given data is received page is reloaded. When there's larger amounts of data sent via Server Sent Events channel, page starts being unresponsive beyond recovery. There's no chance to access its console, and there's no CPU activity that could be blamed for lock.

I tracked it as far as I could, an it looks to be directly related to XMLHttpRequest instance being in InvalidState (for really no reason).

To reproduce the case

1. Get into http://ldz-test4.medyk.org/ it's dev version with not minified scripts so you can more easily track what's going in
2. Open Web Inspector with console visible
3. Login (blue "INGRESE" button in top right corner) with email: mariusz at medikoo.com password: 11111q
4. It should work fine, still you already should notice some invalid states of Xhr reported in a console, that already should not happen.
5. Logout (Red switch in top right corner)
7. Login again but this time with user for which bigger amount of data is loaded: email: supermario at ldz.org password: abc123
8. Most likely page will hang, either during Xhr call or shortly after

After you reload you'll appear logged in, you can repeat that by logging out and switching to other user and so on (to assure big data flow in SSE channel you need to login with other user than one that was logged in before).

This happens only in WebKit (including latest Safari). Other browsers in they're major version, work excellent.

Worst is, that I don't have idea how to workaround it, so with this bug on I can't provide proper support for Safari.

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