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davidedmundson added a comment.


  To expand on the DBus problem:
  
  The connection object resides in a thread; but emits stuff from the main thread. 
  DBus is generally thread safe, but QDBusAbstractAdaptor uses sender() in relaying so isn't.
  
  add in a bouncer, things work nicely:
  
    connect(this, &Connection::deviceRemoved, this, [this](Device* device) {
              emit deviceRemovedSysName(device->sysName());
      });   
  
  this gets implicitly queuedconnection as this is emitted in another thread and it all works. Huzzah
  
  However, we still get a tonne of warnings because we're emitting a bunch of other signals, and internally in QDBusAbstractAdaptor we have the warning about checking for threads*before* we see if actually relays the signal.
  
  The only solution I can see is to make an explicit adaptor.
  
  (or we change the KCM side to use org.freedesktop.DBus.ObjectManager and forget putting anything in here)

REPOSITORY
  R108 KWin

REVISION DETAIL
  https://phabricator.kde.org/D3479

EMAIL PREFERENCES
  https://phabricator.kde.org/settings/panel/emailpreferences/

To: subdiff, #kwin, #plasma, davidedmundson
Cc: graesslin, davidedmundson, plasma-devel, kwin, #kwin, lesliezhai, ali-mohamed, jensreuterberg, abetts, sebas

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<table><tr><td=20style=3D"">davidedmundson=20added=20a=20comment.
</td><a=20style=3D"text-decoration:=20none;=20padding:=204px=208px;=20margi=
n:=200=208px=208px;=20float:=20right;=20color:=20#464C5C;=20font-weight:=20=
bold;=20border-radius:=203px;=20background-color:=20#F7F7F9;=20background-i=
mage:=20linear-gradient(to=20bottom,#fff,#f1f0f1);=20display:=20inline-bloc=
k;=20border:=201px=20solid=20rgba(71,87,120,.2);"=20href=3D"https://phabric=
ator.kde.org/D3479"=20rel=3D"noreferrer">View=20Revision</a></tr></table><b=
r=20/><div><div><p>To=20expand=20on=20the=20DBus=20problem:</p>

<p>The=20connection=20object=20resides=20in=20a=20thread;=20but=20emits=20s=
tuff=20from=20the=20main=20thread.=20<br=20/>
DBus=20is=20generally=20thread=20safe,=20but=20QDBusAbstractAdaptor=20uses=
=20sender()=20in=20relaying=20so=20isn&#039;t.</p>

<p>add=20in=20a=20bouncer,=20things=20work=20nicely:</p>

<div=20class=3D"remarkup-code-block"=20style=3D"margin:=2012px=200;"=20data=
-code-lang=3D"text"=20data-sigil=3D"remarkup-code-block"><pre=20class=3D"re=
markup-code"=20style=3D"font:=2011px/15px=20&quot;Menlo&quot;,=20&quot;Cons=
olas&quot;,=20&quot;Monaco&quot;,=20monospace;=20padding:=2012px;=20margin:=
=200;=20background:=20rgba(71,=2087,=20120,=200.08);">connect(this,=20&amp;=
Connection::deviceRemoved,=20this,=20[this](Device*=20device)=20{
=20=20=20=20=20=20=20=20=20=20emit=20deviceRemovedSysName(device-&gt;sysNam=
e());
=20=20});</pre></div>

<p>this=20gets=20implicitly=20queuedconnection=20as=20this=20is=20emitted=
=20in=20another=20thread=20and=20it=20all=20works.=20Huzzah</p>

<p>However,=20we=20still=20get=20a=20tonne=20of=20warnings=20because=20we&#=
039;re=20emitting=20a=20bunch=20of=20other=20signals,=20and=20internally=20=
in=20QDBusAbstractAdaptor=20we=20have=20the=20warning=20about=20checking=20=
for=20threads*before*=20we=20see=20if=20actually=20relays=20the=20signal.</=
p>

<p>The=20only=20solution=20I=20can=20see=20is=20to=20make=20an=20explicit=
=20adaptor.</p>

<p>(or=20we=20change=20the=20KCM=20side=20to=20use=20org.freedesktop.DBus.O=
bjectManager=20and=20forget=20putting=20anything=20in=20here)</p></div></di=
v><br=20/><div><strong>REPOSITORY</strong><div><div>R108=20KWin</div></div>=
</div><br=20/><div><strong>REVISION=20DETAIL</strong><div><a=20href=3D"http=
s://phabricator.kde.org/D3479"=20rel=3D"noreferrer">https://phabricator.kde=
.org/D3479</a></div></div><br=20/><div><strong>EMAIL=20PREFERENCES</strong>=
<div><a=20href=3D"https://phabricator.kde.org/settings/panel/emailpreferenc=
es/"=20rel=3D"noreferrer">https://phabricator.kde.org/settings/panel/emailp=
references/</a></div></div><br=20/><div><strong>To:=20</strong>subdiff,=20K=
Win,=20Plasma,=20davidedmundson<br=20/><strong>Cc:=20</strong>graesslin,=20=
davidedmundson,=20plasma-devel,=20kwin,=20KWin,=20lesliezhai,=20ali-mohamed=
,=20jensreuterberg,=20abetts,=20sebas<br=20/></div>
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