falkon goes to 100% CPU usage when trying to open some non-http URI schemes

I guess fixing the mimetypes would solve that. So it is not a problem in featherpad, it's a general problem in application handling.

I had some suspicions it might be something like mimetypes, So what should this bug be filed against?

Talked with wxl about yesterday - maybe against the Lubuntu settings/branding package

Sun02Sep2018 1515 < wxl:#lxqt-dev> agaida: excuse me if this is the wrong forum for this, but are you saying that https://bugs.launchpad.net/bugs/1788542 is a general lxqt bug?
Sun02Sep2018 1516 <+agaida:#lxqt-dev> it's a general problem in application and mime handling
Sun02Sep2018 1516 < wxl:#lxqt-dev> so a more system-wide problem is what you're suggesting?
Sun02Sep2018 1516 <+agaida:#lxqt-dev> not limited to LXQt - heck, you can even notice that in Windows
Sun02Sep2018 1517 < wxl:#lxqt-dev> siiiiiiiigh
Sun02Sep2018 1517 <+agaida:#lxqt-dev> :P
Sun02Sep2018 1517 <+agaida:#lxqt-dev> it's a bit complicated
Sun02Sep2018 1518 <+agaida:#lxqt-dev> some applications provide 'hints' for the applications they handle
Sun02Sep2018 1518 <+agaida:#lxqt-dev> the last installed application for a mimetype wins
Sun02Sep2018 1518 < wxl:#lxqt-dev> oh wow jeez
Sun02Sep2018 1519 <+agaida:#lxqt-dev> maybe you remember the funny bug if audacious handle nodes
Sun02Sep2018 1519 <+agaida:#lxqt-dev> and try to play a directory :D
Sun02Sep2018 1519 < wxl:#lxqt-dev> do you think it
Sun02Sep2018 1520 <+agaida:#lxqt-dev> thats a shortcoming in the freedesktop definiton for mime-types - one cant provide priorities in desktop files
Sun02Sep2018 1520 < wxl:#lxqt-dev> s something we could do through default-settings?
Sun02Sep2018 1520 < wxl:#lxqt-dev> or does that run the risk of it being overwritten by something else?
Sun02Sep2018 1520 <+agaida:#lxqt-dev> erm - dunno, where and in which order the things are read
Sun02Sep2018 1521 < wxl:#lxqt-dev> alright i'll play with it and see what i can figure out. thanks for the hints
Sun02Sep2018 1521 <+agaida:#lxqt-dev> strace xdg-open might give a clue
Sun02Sep2018 1521 < wxl:#lxqt-dev> btw has anyone ever filed a bug against freedesktop to get priorities added?
Sun02Sep2018 1522 <+agaida:#lxqt-dev> and ofcourse - ir there is a mimetype list in ~/.config - that would help too, no program will override it
Sun02Sep2018 1522 <+agaida:#lxqt-dev> best bet is to talk with tsujan, palinek or luis about
Sun02Sep2018 1522 < wxl:#lxqt-dev> ok
Sun02Sep2018 1522 < wxl:#lxqt-dev> thanks again
Sun02Sep2018 1523 <+agaida:#lxqt-dev> and i guess there was more than one rant about - i know this dumbfuck sind 2009 - was some of the first things i encountered in linux
Sun02Sep2018 1524 < wxl:#lxqt-dev> that's what i feared :)
Sun02Sep2018 1525 <+agaida:#lxqt-dev> if you think about it more - it isn't easy to solve, best would be a kind of alternatives like for applications - and even this alternatives system is only in debian and derivatives
Sun02Sep2018 1525 < wxl:#lxqt-dev> yeah
Sun02Sep2018 1526 <+agaida:#lxqt-dev> and nobody really knows it or is able to create a alternative by hand :D
Sun02Sep2018 1527 <+agaida:#lxqt-dev> nice thing about: if this follows the normal xdg handling there should be a place inbetween the upstream and user stage distributions could use
Sun02Sep2018 1528 <+agaida:#lxqt-dev> should be traceble with strace - and maybe gio documentation too
Sun02Sep2018 1530 -!- Irssi: You are now talking in #lxqt-dev
Sun02Sep2018 1530 < wxl:#lxqt-dev> well i guess that will tell me which application wins
Sun02Sep2018 1530 < wxl:#lxqt-dev>...

tl;dr it's kind of a freedesktop problem because there are no priorities for mime-types, but that wouldn't be easy to fix, just like alternatives aren't (this is a debian only thing).

otherwise, we got two options:
 1. trying to rearrange the order of application installation to make sure the one we want is installed last (fragile)
 2. adding something to skel to give each user a set mime-type, which will always overwrite everything no matter what (potentially problematic)

it's possible stracing us might lead us to some other solution. gio might offer some help, too, as it does mime detection with xdg-mime.

Actually, it's falkon's fault. It flips out for whatever reason. Firefox has no such problem.

FWIW the chrome-error://chromewebdata/ thing also occurs with qutebrowser, another QtWebEngine browser, but it does not go to 100% usage, though it does fail to load the mail client.

Upstream bug report:
https://bugs.kde.org/show_bug.cgi?id=398222

I also get this with url that involve tel: and sftp: the same problem for falkon.

Upstream says they can't reproduce anymore. Curious.

Confirmed it's working fine in master if you have an email client installed. Otherwise it goes into a loop.

The loop makes sense: xdg-open mailto:<email address hidden> opens falkon, which then opens xdg-open mailto:<email address hidden> which opens falkon, etc.

With an email client, falkon mailto:<email address hidden> opens xdg-open mailto:<email address hidden> which opens $email_client mailto:<email address hidden>.