<table><tr><td style="">ahmadsamir added a comment.
</td><a style="text-decoration: none; padding: 4px 8px; margin: 0 8px 8px; float: right; color: #464C5C; font-weight: bold; border-radius: 3px; background-color: #F7F7F9; background-image: linear-gradient(to bottom,#fff,#f1f0f1); display: inline-block; border: 1px solid rgba(71,87,120,.2);" href="https://phabricator.kde.org/D23902">View Revision</a></tr></table><br /><div><div><blockquote style="border-left: 3px solid #8C98B8;
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<div style="font-style: normal;
padding-bottom: 4px;">In <a href="https://phabricator.kde.org/D23902#542046" style="background-color: #e7e7e7;
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color: black;text-decoration: line-through;">D23902#542046</a>, <a href="https://phabricator.kde.org/p/dfaure/" style="
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<div style="font-style: normal;
padding-bottom: 4px;">In <a href="https://phabricator.kde.org/D23902#542037" style="background-color: #e7e7e7;
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color: black;text-decoration: line-through;">D23902#542037</a>, <a href="https://phabricator.kde.org/p/ahmadsamir/" style="
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<div style="font-style: normal;
padding-bottom: 4px;">In <a href="https://phabricator.kde.org/D23902#542026" style="background-color: #e7e7e7;
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color: rgb(107, 116, 140);"><p>For the record, JFBastien was actually wrong. Calling .begin() on a const return value does call the const overload. Testcase <a href="http://www.davidfaure.fr/kde/const_retval.cpp" class="remarkup-link" target="_blank" rel="noreferrer">http://www.davidfaure.fr/kde/const_retval.cpp</a></p></div>
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<p>That looks like a failure in communication, either one of you _assumed_ something but didn't tell the other. :D</p></div>
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<p>You and I are both entitled to our own opinion, I know what I asked and what the reply was :-P<br />
(I tried to reach him afterwards via linkedin and cppcon slack, no success)</p>
<blockquote style="border-left: 3px solid #a7b5bf; color: #464c5c; font-style: italic; margin: 4px 0 12px 0; padding: 4px 12px; background-color: #f8f9fc;"><blockquote style="border-left: 3px solid #a7b5bf; color: #464c5c; font-style: italic; margin: 4px 0 12px 0; padding: 4px 12px; background-color: #f8f9fc;"><p>But returning const QList would inhibit move semantics, e.g. <tt style="background: #ebebeb; font-size: 13px;">QList<int> mylist = foo();</tt> copies instead of moving.<br />
So yeah, better not do that.</p></blockquote>
<p>And it would detach (I don't know why it feels like detaching for Qt containers is like a sword hanging over all, especially new, developers' heads; so implicit sharing is great, except you have to worry about the container detaching for the rest of its natural life... :)).</p></blockquote>
<p>No, a copy doesn't detach. A non-const method call on a copy detaches.</p></div>
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<p>See? I actually was talking about calling a non-const method, begin(), on a non-const Qt container (or a copy of it), that would make it detach even if it never gets actually modified in the loop, that's what I was thinking in my head. So I _assumed_ it got the point across but because I posted that right under your post about move semantics that kicked the point out the window; so you assumed I was talking about move semantics. Assumptions are bad, man I am telling you.... :)</p>
<blockquote style="border-left: 3px solid #a7b5bf; color: #464c5c; font-style: italic; margin: 4px 0 12px 0; padding: 4px 12px; background-color: #f8f9fc;"><p>And usually you don't have to worry about that. Detaching happens when it should, i.e. when modifying a copy, that's intended. The problem is range-for, which came up later, and which throws ease-of-use a little bit out of the window indeed.</p></blockquote>
<p>Well, I _guess_ the devs who wrote the range for code did that with STL containers in mind, where you're OK if you don't change the container _size_ (IIUC). They probably weren't thinking about the implicitly shared containers created by the Qt devs?</p>
<p>Anyway, thanks for sharing.</p></div></div><br /><div><strong>REPOSITORY</strong><div><div>R241 KIO</div></div></div><br /><div><strong>REVISION DETAIL</strong><div><a href="https://phabricator.kde.org/D23902">https://phabricator.kde.org/D23902</a></div></div><br /><div><strong>To: </strong>ahmadsamir, kde-frameworks-devel, dfaure<br /><strong>Cc: </strong>kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns<br /></div>