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| author | Marc Mutz <marc.mutz@kdab.com> | 2021-06-25 23:54:05 +0200 |
|---|---|---|
| committer | Qt Cherry-pick Bot <cherrypick_bot@qt-project.org> | 2021-06-28 15:04:44 +0000 |
| commit | 3f8e0c31078d100da6218fed3f6635c65e032e3c (patch) | |
| tree | af8b9014a00df8e317698565394c480aaec6e6de | |
| parent | eb4b6e8f3574296e1f864fc7a5dfdef147bc5839 (diff) | |
QVarLengthArray: fix aliasing error in insert(it, n, v)
Taking the copy after the resize is completely pointless: the copy is
there to ensure that `t`, being a reference potentially aliasing an
element in [begin(), end()[ before the resize(), isn't invalidated by
the resize(), so it must be taken before resize().
Add a comment so the next rewrite doesn't cause this to be mixed up
again.
[ChangeLog][QtCore][QVarLengthArray] Fixed an aliasing bug affecting
insertions of objects aliasing existing elements.
Change-Id: I26bc449fa99bf8d09a19147a12a69ac4314cc61d
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
(cherry picked from commit 6e57e41f9aef5ccfa122c10bc6253d47dafd93d2)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
| -rw-r--r-- | src/corelib/tools/qvarlengtharray.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/corelib/tools/qvarlengtharray.h b/src/corelib/tools/qvarlengtharray.h index 5738baae0c..24505d629b 100644 --- a/src/corelib/tools/qvarlengtharray.h +++ b/src/corelib/tools/qvarlengtharray.h @@ -647,8 +647,8 @@ Q_OUTOFLINE_TEMPLATE typename QVarLengthArray<T, Prealloc>::iterator QVarLengthA qsizetype offset = qsizetype(before - ptr); if (n != 0) { + const T copy(t); // `t` could alias an element in [begin(), end()[ resize(s + n); - const T copy(t); if (!QTypeInfo<T>::isRelocatable) { T *b = ptr + offset; T *j = ptr + s; |