tdf#147008 sw_fieldmarkhide: fix invalid NonTextFieldmark positions

Commit ab6176e88f78d0b3aa2490fbc7858304c2d4a437 introduced a crash
in ModelToViewHelper when the positions of a NonTextFieldmark are invalid.

The NonTextFieldmark must always contain 1 CH_TXT_ATR_FORMELEMENT
but after SplitNode() the position is
(rr) p *pFieldMark->m_pPos1
$2 = SwPosition (node 10, offset 1)
(rr) p *pFieldMark->m_pPos2
$3 = SwPosition (node 9, offset 0)

This is because in ContentIdxStoreImpl::SaveBkmks() there is an
asymmetry where the m_pPos2 is recorded to be wrongly corrected to node
9, but if the positions were swapped so that m_pPos1 is the start
position, then it will not be recorded and remain in node 10.

So fix this by changing the NonTextFieldmark to insert its
CH_TXT_ATR_FORMELEMENT differently.

There is some very subtle code in SwTextNode::Update() that is again
asymmetric and (non-obviously) prefers to move m_pPos2 and leave m_pPos1
alone (by moving it to aTmpIdxReg) in case the positions are equal.

But then the fieldmark code increments "rEnd" (which is really the
m_pPos1 i.e. the start after InsertString() returns), and then
decrements m_pPos2.

So avoid the problem by removing these 2 pointless adjustments.

Then it turns a bunch of tests fail because other code assumes that
m_pPos1 is the end of the NonTextFieldmark, so fix
MarkManager::changeFormFieldmarkType(), ModelToViewHelper and
SwHistoryNoTextFieldmark to use GetMarkStart().

Change-Id: I7c82f9a67661121662c95727e0f8f15e06d85a3a
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129289
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
(cherry picked from commit ea06852ee87531794f07710de496734a647a9062)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129265
Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/sw/qa/extras/uiwriter/uiwriter2.cxx b/sw/qa/extras/uiwriter/uiwriter2.cxx
index 79aa517c66f4..65142dbd64e1 100644
--- a/sw/qa/extras/uiwriter/uiwriter2.cxx
+++ b/sw/qa/extras/uiwriter/uiwriter2.cxx
@@ -3600,6 +3600,14 @@ CPPUNIT_TEST_FIXTURE(SwUiWriterTest2, testCheckboxFormFieldInsertion)
     pFieldmark = dynamic_cast<::sw::mark::IFieldmark*>(*aIter);
     CPPUNIT_ASSERT(pFieldmark);
     CPPUNIT_ASSERT_EQUAL(OUString(ODF_FORMCHECKBOX), pFieldmark->GetFieldname());
+
+    // tdf#147008 this would crash
+    SwWrtShell* pWrtShell = pDoc->GetDocShell()->GetWrtShell();
+    pWrtShell->StartOfSection(false);
+    pWrtShell->SplitNode();
+    CPPUNIT_ASSERT_EQUAL(pFieldmark->GetMarkPos().nNode, pFieldmark->GetOtherMarkPos().nNode);
+    CPPUNIT_ASSERT_EQUAL(sal_Int32(pFieldmark->GetMarkPos().nContent.GetIndex() + 1),
+                         pFieldmark->GetOtherMarkPos().nContent.GetIndex());
 }
 
 CPPUNIT_TEST_FIXTURE(SwUiWriterTest2, testDropDownFormFieldInsertion)