fix crash in select-all

<vmiklos> noelgrandin: hmm, when simply typing "a\nb\nc\d" into writer
and trying to select-all, i get a crash from the new
SwFrame::DynCastTextFrame(). is that something you see?
https://pastebin.com/raw/v00ncxXP is the backtrace
<vmiklos> sounds like the old code invoked dynamic_cast<> on nullptr
fine, but the new pFoo->DynCastTextFrame() won't work if pFoo is nullptr
<noelgrandin> vmiklos, doh!, thanks, will fix

Change-Id: I58966512551e90ded3d3ecd65fef9f083dc6d852
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/121365
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 4 insertions, 2 deletions

diff --git a/sw/source/core/docnode/node.cxx b/sw/source/core/docnode/node.cxx
index 67bf030fa8d8..d7a2a6ba7116 100644
--- a/sw/source/core/docnode/node.cxx
+++ b/sw/source/core/docnode/node.cxx
@@ -1392,9 +1392,11 @@ void SwContentNode::MakeFramesForAdjacentContentNode(SwContentNode& rNode)
             if ( pViewShell && pViewShell->GetLayout() &&
                  pViewShell->GetLayout()->IsAnyShellAccessible() )
             {
+                auto pNext = pNew->FindNextCnt( true );
+                auto pPrev = pNew->FindPrevCnt();
                 pViewShell->InvalidateAccessibleParaFlowRelation(
-                            pNew->FindNextCnt( true )->DynCastTextFrame(),
-                            pNew->FindPrevCnt()->DynCastTextFrame() );
+                            pNext ? pNext->DynCastTextFrame() : nullptr,
+                            pPrev ? pPrev->DynCastTextFrame() : nullptr );
             }
         }
     }