tdf#135457 sw: fix invalidation of SwXTextField

This was supposed to happen from SwNodes::ChgNode() when moving to the
undo nodes array.

There are fields with a range that contains other fields, when the outer
field's range is deleted, the contained field moves to the undo array
and its position is no longer valid to be given out by
SwXTextField::getAnchor().

(regression from c73b5e969b2f9abdb2b9191938ca30bec5af725d)

Change-Id: I38c8b3393a777ca8dc8739b5ca4233a7f124961e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/100749
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@cib.de>
(cherry picked from commit 14fd4b54113f884cfd6871aeff693734fc06224b)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/100705
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/sw/source/core/txtnode/atrfld.cxx b/sw/source/core/txtnode/atrfld.cxx
index b41eb94..b8027bc 100644
--- a/sw/source/core/txtnode/atrfld.cxx
+++ b/sw/source/core/txtnode/atrfld.cxx
@@ -217,7 +217,7 @@ void SwFormatField::InvalidateField()
{
    SwPtrMsgPoolItem const item(RES_REMOVE_UNO_OBJECT,
            &static_cast<SwModify&>(*this)); // cast to base class (void*)
    NotifyClients(&item, &item);
    CallSwClientNotify(sw::LegacyModifyHint{ &item, &item });
}

void SwFormatField::SwClientNotify( const SwModify& rModify, const SfxHint& rHint )
diff --git a/sw/source/core/undo/undobj.cxx b/sw/source/core/undo/undobj.cxx
index 30fc2ed..a7a6119 100644
--- a/sw/source/core/undo/undobj.cxx
+++ b/sw/source/core/undo/undobj.cxx
@@ -853,6 +853,10 @@ void SwUndoSaveContent::DelContentIndex( const SwPosition& rMark,

    SwDoc* pDoc = rMark.nNode.GetNode().GetDoc();

    // if it's not in the doc array, probably missing some invalidation somewhere
    assert(&rPoint.nNode.GetNodes() == &pDoc->GetNodes());
    assert(&rMark.nNode.GetNodes() == &pDoc->GetNodes());

    ::sw::UndoGuard const undoGuard(pDoc->GetIDocumentUndoRedo());

    // 1. Footnotes