sw floattable: fix assert fail when object formatter gets the wrong anchor

A subset of the tdf#155002 bugdoc hit an assertion failure in
SwObjectFormatterTextFrame::DoFormatObj() for multi-page floating
tables.

What happens is that a section frame wants to format its content, calls
CalcContent(), which assumes that the text frame's all draw objects are
also on the same page, as long as they are at-para anchored. This is
true for at-para anchored images, but not for split flys.

Fix the problem by using FindAnchorCharFrame() to know if the anchored
object should be inside the master anchor or a follow anchor: that
allows invoking SwObjectFormatter::FormatObj() with the correct anchor
and page frames, so we don't hit the assertion failure.

The hang with the original tdf#155002 bugdoc needs more work, still.

(cherry picked from commit b47401e12d9c45386899df0aa26653bd26c9abd4)

Change-Id: I2b4d88ccb2ff251c0b0811c31d2aa85053143443
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/152141
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>

3 files changed, 46 insertions, 1 deletions

diff --git a/sw/qa/core/layout/data/floattable-object-formatter.docx b/sw/qa/core/layout/data/floattable-object-formatter.docx
new file mode 100644
index 000000000000..2582af0eb863
--- /dev/null
+++ b/sw/qa/core/layout/data/floattable-object-formatter.docx
diff --git a/sw/qa/core/layout/flycnt.cxx b/sw/qa/core/layout/flycnt.cxx
index 3c6a061cb962..83889ceecef0 100644
--- a/sw/qa/core/layout/flycnt.cxx
+++ b/sw/qa/core/layout/flycnt.cxx
@@ -885,6 +885,31 @@ CPPUNIT_TEST_FIXTURE(Test, testSplitFlyTabJoinLegacy)
     CPPUNIT_ASSERT(pPage3);
     CPPUNIT_ASSERT(!pPage3->GetSortedObjs());
 }
+
+CPPUNIT_TEST_FIXTURE(Test, testSplitFlyObjectFormatter)
+{
+    // Given a document with 3 pages and 2 tables: table on first and second page, 3rd page has no
+    // table:
+    createSwDoc("floattable-object-formatter.docx");
+
+    // When calculating the layout:
+    calcLayout();
+
+    // Then make sure we don't crash and also that all pages have the expected amount of fly frames:
+    SwDoc* pDoc = getSwDoc();
+    SwRootFrame* pLayout = pDoc->getIDocumentLayoutAccess().GetCurrentLayout();
+    auto pPage1 = dynamic_cast<SwPageFrame*>(pLayout->Lower());
+    CPPUNIT_ASSERT(pPage1);
+    const SwSortedObjs& rPage1Objs = *pPage1->GetSortedObjs();
+    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), rPage1Objs.size());
+    auto pPage2 = dynamic_cast<SwPageFrame*>(pPage1->GetNext());
+    CPPUNIT_ASSERT(pPage2);
+    const SwSortedObjs& rPage2Objs = *pPage2->GetSortedObjs();
+    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1), rPage2Objs.size());
+    auto pPage3 = dynamic_cast<SwPageFrame*>(pPage2->GetNext());
+    CPPUNIT_ASSERT(pPage3);
+    CPPUNIT_ASSERT(!pPage3->GetSortedObjs());
+}
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sw/source/core/layout/fly.cxx b/sw/source/core/layout/fly.cxx
index b598346216ee..054e86525180 100644
--- a/sw/source/core/layout/fly.cxx
+++ b/sw/source/core/layout/fly.cxx
@@ -1679,7 +1679,27 @@ void CalcContent( SwLayoutFrame *pLay, bool bNoColl )
                         // anchored objects.
                         //pAnchoredObj->InvalidateObjPos();
                         SwRect aRect( pAnchoredObj->GetObjRect() );
-                        if ( !SwObjectFormatter::FormatObj( *pAnchoredObj, pFrame, pPageFrame ) )
+
+                        SwFrame* pAnchorFrame = pFrame;
+                        SwPageFrame* pAnchorPageFrame = pPageFrame;
+                        if (SwFlyFrame* pFlyFrame = pAnchoredObj->DynCastFlyFrame())
+                        {
+                            if (pFlyFrame->IsFlySplitAllowed())
+                            {
+                                // Split flys are at-para anchored, but the follow fly's anchor char
+                                // frame is not the master frame but can be also a follow of pFrame.
+                                SwTextFrame* pAnchorCharFrame = pFlyFrame->FindAnchorCharFrame();
+                                if (pAnchorCharFrame)
+                                {
+                                    // Found an anchor char frame, update the anchor frame and the
+                                    // anchor page frame accordingly.
+                                    pAnchorFrame = pAnchorCharFrame;
+                                    pAnchorPageFrame = pAnchorCharFrame->FindPageFrame();
+                                }
+                            }
+                        }
+
+                        if ( !SwObjectFormatter::FormatObj( *pAnchoredObj, pAnchorFrame, pAnchorPageFrame ) )
                         {
                             bRestartLayoutProcess = true;
                             break;