Make sure removed QTextBlock is invalid

If the block is removed from document block map, we will mark the
right node to the current head->freelist index, but it shouldn't
be accessed directly, otherwise it can cause crash because of
uninitialized node.

Hence we need to check if a node index is equal to current freelist
index. If so, it cannot be a valid block.

Task-number: QTBUG-18500
Reviewed-by: Eskil

1 files changed, 12 insertions, 0 deletions

diff --git a/tests/auto/qtextblock/tst_qtextblock.cpp b/tests/auto/qtextblock/tst_qtextblock.cpp
index cec3a6a..748d921 100644
--- a/tests/auto/qtextblock/tst_qtextblock.cpp
+++ b/tests/auto/qtextblock/tst_qtextblock.cpp
@@ -76,6 +76,7 @@ private slots:
     void excludeParagraphSeparatorFragment();
     void backwardsBlockIterator();
     void previousBlock_qtbug18026();
+    void removedBlock_qtbug18500();
 
 private:
     QTextDocument *doc;
@@ -181,5 +182,16 @@ void tst_QTextBlock::previousBlock_qtbug18026()
     QVERIFY(last.isValid());
 }
 
+void tst_QTextBlock::removedBlock_qtbug18500()
+{
+    cursor.insertText("line 1\nline 2\nline 3 \nline 4\n");
+    cursor.setPosition(7);
+    QTextBlock block = cursor.block();
+    cursor.setPosition(21, QTextCursor::KeepAnchor);
+
+    cursor.removeSelectedText();
+    QVERIFY(!block.isValid());
+}
+
 QTEST_MAIN(tst_QTextBlock)
 #include "tst_qtextblock.moc"