From c62333424839b3229706a6ebb64ba271689a3b8c Mon Sep 17 00:00:00 2001 From: Christian Ehrlicher Date: Sun, 22 Dec 2019 17:53:20 +0100 Subject: QPlainTextEdit: make sure firstVisibleBlock() is valid Under some circumstances it's possible that firstVisibleBlock() returns an invalid block within QPlainTextEditPrivate::_q_textChanged() which results in a nullptr access later on. Therefore add a check similar to other places and test the validity of the returned block before accessing it. Fixes: QTBUG-80929 Change-Id: I1fd4643b10b842acfe1c356048379f0ba225dddf Reviewed-by: Friedemann Kleint Reviewed-by: Timur Pocheptsov --- src/widgets/widgets/qplaintextedit.cpp | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/widgets/widgets/qplaintextedit.cpp b/src/widgets/widgets/qplaintextedit.cpp index e8da720b58..7e9e0fabe9 100644 --- a/src/widgets/widgets/qplaintextedit.cpp +++ b/src/widgets/widgets/qplaintextedit.cpp @@ -839,7 +839,8 @@ void QPlainTextEditPrivate::_q_textChanged() placeholderVisible = !placeholderText.isEmpty() && q->document()->isEmpty() - && q->firstVisibleBlock().layout()->preeditAreaText().isEmpty(); + && (!q->firstVisibleBlock().isValid() || + q->firstVisibleBlock().layout()->preeditAreaText().isEmpty()); if (placeholderCurrentyVisible != placeholderVisible) viewport->update(); -- cgit v1.2.3