Comment 4 for bug 1498539

The bug fix https://codereview.qt-project.org/#/c/120738 links to a bug that indicates QNAM erronously closing queued multiple requests with 'Unknown error' and a warning before that "QIODevice:::write device not open" which matches what the test mentions. And the fix itself states "This patch changes the QNAM socket slot connections to be DirectConnection.
We don't close the socket anymore in slots where it is anyway in a closed state afterwards. This prevents event/stack recursions.". Could the type change to DirectConnection cause this change of behavior?

I've rebuilt Scopes packages, unity8, and download manager to have unit test results in addition to autopilot tests that I did earlier, and it still seems to be that the only flakiness is this webbrowser-app unit test, and on x86 only: https://launchpad.net/~canonical-qt5-edgers/+archive/qt5-beta1/+packages As x86 is faster, maybe there's something timing related.

I've asked pstolowski to look whether he can see a delta with/without the patch. He mentioned there have been some 'device is open' in bug reports in the past, which is one of the symptoms being fixed by the bug fix.

It's also useful to know that this bug fix itself is a bug fix to an earlier fix https://codereview.qt-project.org/#/c/110150/ which upstream urged everyone to ship, and we're currently doing that (in OTA-6). So if we're not seeing worrying regressions, it sounds like a worthwhile bug fix that may help random network failures in QNAM using components.

To switch between with/without patch, the revert of this latter patch is in silo 054. One can use the pinning (https://wiki.ubuntu.com/LandingTeam/SiloTestingGuidelines#Install_silos_with_overlay_PPA_enabled), enabling/disabling the file and "apt upgrade" will allow to both quickly "upgrade to the revert" or "downgrade to the fix that was landed".