Fix an Assert in QTextTable

The problem was caused by the fragment id being inserted
in front of a cell spanning over several rows instead of
the next logical cell (or fragment_end) in the cells structure.

Task-number: QTBUG-11282
Reviewed-by: Simon Hausmann
(cherry picked from commit d3a6f124dde7732311ad9312ebf41997712fc6bb)

2 files changed, 79 insertions, 4 deletions

diff --git a/src/gui/text/qtexttable.cpp b/src/gui/text/qtexttable.cpp
index aa8d8ce..b39ceb7 100644
--- a/src/gui/text/qtexttable.cpp
+++ b/src/gui/text/qtexttable.cpp
@@ -754,19 +754,39 @@ void QTextTable::insertColumns(int pos, int num)
     QTextFormatCollection *c = p->formatCollection();
     p->beginEditBlock();
 
+    QList<int> extendedSpans;
     for (int i = 0; i < d->nRows; ++i) {
         int cell;
         if (i == d->nRows - 1 && pos == d->nCols)
             cell = d->fragment_end;
         else
             cell = d->grid[i*d->nCols + pos];
-        QTextDocumentPrivate::FragmentIterator it(&p->fragmentMap(), cell);
-        QTextCharFormat fmt = c->charFormat(it->format);
         if (pos > 0 && pos < d->nCols && cell == d->grid[i*d->nCols + pos - 1]) {
             // cell spans the insertion place, extend it
-            fmt.setTableCellColumnSpan(fmt.tableCellColumnSpan() + num);
-            p->setCharFormat(it.position(), 1, fmt);
+            if (!extendedSpans.contains(cell)) {
+                QTextDocumentPrivate::FragmentIterator it(&p->fragmentMap(), cell);
+                QTextCharFormat fmt = c->charFormat(it->format);
+                fmt.setTableCellColumnSpan(fmt.tableCellColumnSpan() + num);
+                p->setCharFormat(it.position(), 1, fmt);
+                d->dirty = true;
+                extendedSpans << cell;
+            }
         } else {
+            /* If the next cell is spanned from the row above, we need to find the right position
+            to insert to */
+            if (i > 0 && pos < d->nCols && cell == d->grid[(i-1) * d->nCols + pos]) {
+                int gridIndex = i*d->nCols + pos;
+                const int gridEnd = d->nRows * d->nCols - 1;
+                while (gridIndex < gridEnd && cell == d->grid[gridIndex]) {
+                    ++gridIndex;
+                }
+                if (gridIndex == gridEnd)
+                    cell = d->fragment_end;
+                else
+                    cell = d->grid[gridIndex];
+            }
+            QTextDocumentPrivate::FragmentIterator it(&p->fragmentMap(), cell);
+            QTextCharFormat fmt = c->charFormat(it->format);
             fmt.setTableCellRowSpan(1);
             fmt.setTableCellColumnSpan(1);
             Q_ASSERT(fmt.objectIndex() == objectIndex());
diff --git a/tests/auto/qtexttable/tst_qtexttable.cpp b/tests/auto/qtexttable/tst_qtexttable.cpp
index 43d3d1b..f2c9309 100644
--- a/tests/auto/qtexttable/tst_qtexttable.cpp
+++ b/tests/auto/qtexttable/tst_qtexttable.cpp
@@ -48,9 +48,14 @@
 #include <qtexttable.h>
 #include <qdebug.h>
 #include <qtextcursor.h>
+#include <qtextdocument.h>
+#include <qtextedit.h>
 
 //TESTED_FILES=
 
+typedef QList<int> IntList;
+Q_DECLARE_METATYPE(IntList)
+
 QT_FORWARD_DECLARE_CLASS(QTextDocument)
 
 class tst_QTextTable : public QObject
@@ -78,6 +83,7 @@ private slots:
     void insertRows();
     void deleteInTable();
     void mergeCells();
+    void mergeAndInsert();
     void splitCells();
     void blocksForTableShouldHaveEmptyFormat();
     void removeTableByRemoveRows();
@@ -93,6 +99,8 @@ private slots:
     void removeColumns3();
     void removeColumns4();
     void removeColumns5();
+    void QTBUG11282_insertBeforeMergedEnding_data();
+    void QTBUG11282_insertBeforeMergedEnding();
 
 private:
     QTextTable *create2x2Table();
@@ -586,6 +594,16 @@ void tst_QTextTable::mergeCells()
     QVERIFY(table->cellAt(0, 1) == table->cellAt(1, 1));
 }
 
+void tst_QTextTable::mergeAndInsert()
+{
+    QTextTable *table = cursor.insertTable(4,3);
+    table->mergeCells(0,1,3,2);
+    table->mergeCells(3,0,1,3);
+    //Don't crash !
+    table->insertColumns(1,2);
+    QCOMPARE(table->columns(), 5);
+}
+
 void tst_QTextTable::splitCells()
 {
     QTextTable *table = create4x4Table();
@@ -931,5 +949,42 @@ void tst_QTextTable::removeColumns5()
     QCOMPARE(table->cellAt(3, 2).firstPosition(), 11);
 }
 
+void tst_QTextTable::QTBUG11282_insertBeforeMergedEnding_data()
+{
+    QTest::addColumn<int>("rows");
+    QTest::addColumn<int>("columns");
+    QTest::addColumn<QList<int> >("merge");
+    QTest::addColumn<QList<int> >("insert");
+
+    QTest::newRow("2x3, merge two, insert one") << 2 << 3 << (QList<int>() << 1 << 2 << 2)
+            << (QList<int>() << 1 << 1) ;
+    QTest::newRow("3x4, merge three, insert one") << 3 << 4 << (QList<int>() << 1 << 3 << 3)
+            << (QList<int>() << 1 << 1) ;
+    QTest::newRow("4x3, merge two, insert two") << 4 << 3 << (QList<int>() << 1 << 4 << 2)
+            << (QList<int>() << 1 << 2) ;
+    QTest::newRow("4x4, merge middle two, insert one") << 4 << 4 << (QList<int>() << 1 << 4 << 2)
+            << (QList<int>() << 1 << 1) ;
+}
+
+void tst_QTextTable::QTBUG11282_insertBeforeMergedEnding()
+{
+    QFETCH(int, rows);
+    QFETCH(int, columns);
+    QFETCH(QList<int>, merge);
+    QFETCH(QList<int>, insert);
+    QTextTable *table = cursor.insertTable(rows, columns);
+    QTextEdit *textEdit = new QTextEdit;
+    textEdit->setDocument(doc);
+    textEdit->show();
+    QTest::qWaitForWindowShown(textEdit);
+    table->mergeCells(0,merge.at(0), merge.at(1), merge.at(2));
+    //Don't crash !
+    table->insertColumns(insert.at(0), insert.at(1));
+    //Check that the final size is what we expected
+    QCOMPARE(table->rows(), rows);
+    QCOMPARE(table->columns(), columns + insert.at(1));
+    delete textEdit;
+}
+
 QTEST_MAIN(tst_QTextTable)
 #include "tst_qtexttable.moc"