'Re: Review Request 126725: prevent crash-on-exit in KSelectAction::~KSelectAction'

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List:       kde-frameworks-devel
Subject:    Re: Review Request 126725: prevent crash-on-exit in KSelectAction::~KSelectAction
From:       David Faure <faure () kde ! org>
Date:       2016-01-19 7:54:46
Message-ID: 20160119075446.4401.23873 () mimi ! kde ! org
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This is an automatically generated e-mail. To reply, visit:
https://git.reviewboard.kde.org/r/126725/#review91304
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Ship it!

Ship It!

- David Faure

On Jan. 14, 2016, 11:21 a.m., René J.V. Bertin wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/126725/
> -----------------------------------------------------------
> 
> (Updated Jan. 14, 2016, 11:21 a.m.)
> 
> 
> Review request for KDE Frameworks and Christoph Feck.
> 
> 
> Repository: kwidgetsaddons
> 
> 
> Description
> -------
> 
> I was seeing a systematic crash on exitting kdenlive5, on OS X deep under the \
> `delete menu()` instruction in `KSelectAction::~KSelectAction`. The backtrace \
> suggested this might be due to a pending event (or an event due to the menu \
> deletion) being delivered post-mortem to an instance of a QMenu related class. 
> My fix is based on 3 principles:
> 1) release the "foreign" member instance (`menu()`) before releasing the own d-ptr
> 2) Remove the QMenu instance from ourselves before deleting it to have one less \
> potential dangling reference to it 3) QMenu is a QObject descendent that \
> corresponds to a UI element: on OS X it is safer to dispose these through \
> `deleteLater()` rather than directly. 
> 
> Diffs
> -----
> 
> src/kselectaction.cpp 1381099 
> 
> Diff: https://git.reviewboard.kde.org/r/126725/diff/
> 
> 
> Testing
> -------
> 
> On OS X 10.9.5, Qt 5.5.1 and KF5 Frameworks 5.16.0, built for installation under \
> /opt/local . 
> It seems that points 1) and 2) above already solve the crash issue in kdenlive on \
> OS X, but the general principle stands so I suggest keeping 3) in library code like \
> this. 
> 
> Thanks,
> 
> René J.V. Bertin
> 
> 

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      This is an automatically generated e-mail. To reply, visit:
      <a href="https://git.reviewboard.kde.org/r/126725/">https://git.reviewboard.kde.org/r/126725/</a>
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Ship it!

</p>

 <pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: \
-pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Ship It!</pre>  <br />

<p>- David Faure</p>

<br />
<p>On January 14th, 2016, 11:21 a.m. UTC, René J.V. Bertin wrote:</p>

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<div>Review request for KDE Frameworks and Christoph Feck.</div>
<div>By René J.V. Bertin.</div>

<p style="color: grey;"><i>Updated Jan. 14, 2016, 11:21 a.m.</i></p>

<div style="margin-top: 1.5em;">
 <b style="color: #575012; font-size: 10pt;">Repository: </b>
kwidgetsaddons
</div>

<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
 <table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" \
style="border: 1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">I was seeing a systematic crash on exitting kdenlive5, \
on OS X deep under the <code style="text-rendering: inherit;color: #4444cc;padding: \
0;white-space: normal;margin: 0;line-height: inherit;">delete menu()</code> \
instruction in <code style="text-rendering: inherit;color: #4444cc;padding: \
0;white-space: normal;margin: 0;line-height: \
inherit;">KSelectAction::~KSelectAction</code>. The backtrace suggested this might be \
due to a pending event (or an event due to the menu deletion) being delivered \
post-mortem to an instance of a QMenu related class.</p> <p style="padding: \
0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">My \
fix is based on 3 principles: 1) release the "foreign" member instance (<code \
style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: \
0;line-height: inherit;">menu()</code>) before releasing the own d-ptr 2) Remove the \
QMenu instance from ourselves before deleting it to have one less potential dangling \
reference to it 3) QMenu is a QObject descendent that corresponds to a UI element: on \
OS X it is safer to dispose these through <code style="text-rendering: inherit;color: \
#4444cc;padding: 0;white-space: normal;margin: 0;line-height: \
inherit;">deleteLater()</code> rather than directly.</p></pre>  </td>
 </tr>
</table>

<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: \
1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">On OS X 10.9.5, Qt 5.5.1 and KF5 Frameworks 5.16.0, \
built for installation under /opt/local .</p> <p style="padding: 0;text-rendering: \
inherit;margin: 0;line-height: inherit;white-space: inherit;">It seems that points 1) \
and 2) above already solve the crash issue in kdenlive on OS X, but the general \
principle stands so I suggest keeping 3) in library code like this.</p></pre>  </td>
 </tr>
</table>

<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
<ul style="margin-left: 3em; padding-left: 0;">

 <li>src/kselectaction.cpp <span style="color: grey">(1381099)</span></li>

</ul>

<p><a href="https://git.reviewboard.kde.org/r/126725/diff/" style="margin-left: \
3em;">View Diff</a></p>

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