Review Request: Workaround for the hang (freeze) when opening VLC's file dialog under KDE...

[Dawit A]

On Fri, Feb 4, 2011 at 2:46 AM, Thiago Macieira <thiago at kde.org> wrote:
> On Thursday, 3 de February de 2011 22:44:56 Dawit Alemayehu wrote:
>> The attached patch is a workaround to the much discussed issue with VLC
>> hanging when opening a KDE file dialog. For the details about the causes of
>> this bug, see http://lists.kde.org/?t 9572447500001&r1&w2 and the bug
>> report linked above...
>>
>>
>> This addresses bug 260719.
>>     http://bugs.kde.org/show_bug.cgi?id&0719
>
> Hmm... I don't get it. Isn't the database version saved in the database? Why
> do we need to search the pkg-config file (which is a development file!) to find
> out how to use the database?

Dunno the answer, but I am sure if that was available David would have
already used that.

> If this is required, it sounds like shared-mime-info is broken and should be
> fixed instead. I never got why we needed to run a subprocess in the first place.

Well this is only a temporary fix anyhow. It is only there until the
issue is fully resolved and can easily be removed down the road when
the issue is resolved correctly one way or another.

> In the meantime, I've been discussing with Rémi about the issue and he's not
> budging from his position that libraries shoul
>  never use Unix signals. To be
> honest, he's right: Unix signals are meant to be used centrally only. But we
> need SIGCHLD to be notified that a child exited, so we need a compromise
> between apps and libraries.

That is especially true for QProcess. It is used in several place
within kdelibs. If any of those code paths are hit from an app like
VLC, the same issue will manifest itself as well. I am still wondering
whether or not the QtCreator freeze I get to this day is somehow
related to this issue even though I doubt QtCreator does any signal
blocking...