QSyntaxHighlighter: Fix crash when parent is a nullptr

QSyntaxHighlighter has the follwoing constructor taking a QObject

  QSyntaxHighlighter::QSyntaxHighlighter(QObject *parent)
    : QObject(*new QSyntaxHighlighterPrivate, parent)
  {
      if (parent->inherits("QTextEdit")) {
          // ...
      }
  }

Typically, a 'parent' refers to the parent/child hierarchy in Qt
and is allowed to be a nullptr. However, in this case, passing a
nullptr will lead to a crash, as reported in
https://bugs.kde.org/show_bug.cgi?id=404820

This patch makes the QSyntaxHighlighter constructor nullptr safe
by checking if parent is a valid pointer.

Change-Id: Ia4e9b46b94fd37e6ceb2cd0538594353fdc1e349
Reviewed-by: Jesus Fernandez <Jesus.Fernandez@qt.io>
Reviewed-by: Christoph Cullmann <cullmann@kde.org>
This commit is contained in:
Dominik Haumann 2019-02-26 21:30:48 +01:00
parent 96404f7ac8
commit 16cb578a8d

View File

@ -297,7 +297,7 @@ void QSyntaxHighlighterPrivate::reformatBlock(const QTextBlock &block)
QSyntaxHighlighter::QSyntaxHighlighter(QObject *parent)
: QObject(*new QSyntaxHighlighterPrivate, parent)
{
if (parent->inherits("QTextEdit")) {
if (parent && parent->inherits("QTextEdit")) {
QTextDocument *doc = parent->property("document").value<QTextDocument *>();
if (doc)
setDocument(doc);