sw floattable: fix locking in SwTextFrame::Prepare()

Once a floating table is split across 2 pages, we currently emit this
warning:

warn:legacy.osl:23427:23427:sw/source/core/text/txtfrm.cxx:2808: SwTextFrame::Prepare: three of a perfect pair

Which suggests that we want to invalidate the size of a frame that is
already locked.

The way normal frame split doesn't hit this warning is that the master
has some content, then once SwContentFrame::Paste() on the follow calls
SwTextFrame::Prepare() on the master, the !HasPara() condition is not
hit, so it's not a problem that the frame is locked.

Fix this for the split fly case by assuming that in case our offset and
our follow's offset is both 0, then this frame will have some fly
content, so don't return early (similar to what happens when the frame
has some text content).

We may want to revisit this later so that at least an SwParaPortion is
generated for non-last anchors for split flys, but this is good enough
for now, since the point is to not invalidate the size of a locked
frame.

Change-Id: I7c78472653bb6818f0d5880d21f468286be547e4
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/147378
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

1 files changed, 6 insertions, 1 deletions

diff --git a/sw/source/core/text/txtfrm.cxx b/sw/source/core/text/txtfrm.cxx
index 5906c9c9d1f3..7ac2a5183114 100644
--- a/sw/source/core/text/txtfrm.cxx
+++ b/sw/source/core/text/txtfrm.cxx
@@ -2823,7 +2823,12 @@ bool SwTextFrame::Prepare( const PrepareHint ePrep, const void* pVoid,
         }
     }
 
-    if( !HasPara() && PrepareHint::MustFit != ePrep )
+    // Split fly anchors are technically empty (have no SwParaPortion), but otherwise behave like
+    // other split text frames, which are non-empty.
+    bool bSplitFlyAnchor = GetOffset() == TextFrameIndex(0) && HasFollow()
+                           && GetFollow()->GetOffset() == TextFrameIndex(0);
+
+    if( !HasPara() && !bSplitFlyAnchor && PrepareHint::MustFit != ePrep )
     {
         SetInvalidVert( true ); // Test
         OSL_ENSURE( !IsLocked(), "SwTextFrame::Prepare: three of a perfect pair" );