tdf#166879 RTF export: handle section break right after a section

The RTF file opens fine, but saving and opening in either Writer or Word
loses the section break between the two paragraphs.

What happens is that the first paragraph is in a Writer section, and the
second paragraph has an SwFormatPageDesc associated with it. And
RtfExport::OutputEndNode() only emits section breaks for end nodes if
they are the end of a table.

Fix the problem by also handling the end of Writer sections, similar to
how it already works for the DOCX export since commit
7060c7b642 (tdf#95367 DOCX: allow r-t of
changed first/follow sections, 2016-10-10).

The original scenario was around saving a file for the 2nd time, the
testcase includes a subset of Writer's own RTF export result, so just
one import + export is needed.

Change-Id: I5cbb9d1ac740158f798fa43c4357c23d8037ba27
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/186374
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

sw/inc/doc.hxx

@@ -1371,7 +1371,7 @@ public:
             SfxItemSet const*const pAttr, bool const bUpdate = true);
     static sal_uInt16 IsInsRegionAvailable( const SwPaM& rRange,
                                 const SwNode** ppSttNd = nullptr );
-    static SwSection* GetCurrSection( const SwPosition& rPos );
+    SW_DLLPUBLIC static SwSection* GetCurrSection( const SwPosition& rPos );
     SwSectionFormats& GetSections() { return *mpSectionFormatTable; }
     const SwSectionFormats& GetSections() const { return *mpSectionFormatTable; }
     SwSectionFormat *MakeSectionFormat();

sw/qa/extras/rtfexport/data/section-break-after-section.rtf

@@ -0,0 +1,10 @@
+{\rtf1
+\paperw11906\paperh16838\margl1588\margr1588\margt1276\margb1276
+\sectd\sbknone
+\pard\plain\pagebb
+first page\par
+\pard\plain
+\sect
+\sectd \pgwsxn16840\pghsxn11907
+second page\par
+}

sw/qa/extras/rtfexport/rtfexport8.cxx

@@ -482,6 +482,24 @@ CPPUNIT_TEST_FIXTURE(Test, testTdf160976_headerFooter3)
     verify();
 }
 
+CPPUNIT_TEST_FIXTURE(Test, testSectionBreakAfterSection)
+{
+    // Given a document that is modeled with a Writer section, followed by a paragraph with a new
+    // page style ("section break"):
+    createSwDoc("section-break-after-section.rtf");
+
+    // When saving that document to RTF:
+    saveAndReload(mpFilter);
+
+    // Then make sure the 2nd paragraph starts on a new page after export, too:
+    uno::Reference<text::XTextRange> xParagraph = getParagraph(2);
+    // Without the accompanying fix in place, this test would have failed with:
+    // - the property is of unexpected type or void: PageDescName
+    // i.e. the 2nd paragraph was on the same page as the 1st one.
+    auto aPageDescName = getProperty<OUString>(xParagraph, "PageDescName");
+    CPPUNIT_ASSERT(!aPageDescName.isEmpty());
+}
+
 CPPUNIT_TEST_FIXTURE(Test, testTdf158830)
 {
     auto verify = [this]() {

sw/source/filter/ww8/rtfattributeoutput.cxx

@@ -369,11 +369,12 @@ void RtfAttributeOutput::SectionBreaks(const SwNode& rNode)
     }
     else if (rNode.IsEndNode())
     {
-        // End of something: make sure that it's the end of a table.
-        assert(rNode.StartOfSectionNode()->IsTableNode());
+        // End of something: make sure that it's the end of a table or section.
+        assert(rNode.StartOfSectionNode()->IsTableNode()
+               || rNode.StartOfSectionNode()->IsSectionNode());
         if (aNextIndex.GetNode().IsTextNode())
         {
-            // Handle section break between a table and a text node following it.
+            // Handle section break between the end node and a text node following it.
             const SwTextNode* pTextNode = aNextIndex.GetNode().GetTextNode();
             m_rExport.OutputSectionBreaks(pTextNode->GetpSwAttrSet(), *pTextNode);
         }

sw/source/filter/ww8/rtfexport.cxx

@@ -1124,7 +1124,17 @@ bool RtfExport::DisallowInheritingOutlineNumbering(const SwFormat& rFormat)
 
 void RtfExport::OutputEndNode(const SwEndNode& rEndNode)
 {
-    if (TXT_MAINTEXT == m_nTextTyp && rEndNode.StartOfSectionNode()->IsTableNode())
+    if (TXT_MAINTEXT == m_nTextTyp && rEndNode.StartOfSectionNode()->IsSectionNode())
+    {
+        // Only consider the end of toplevel sections.
+        SwPosition aNodePosition(rEndNode);
+        SwSection* pSect = SwDoc::GetCurrSection(aNodePosition);
+        if (pSect && pSect->GetParent())
+            return;
+
+        AttrOutput().SectionBreaks(rEndNode);
+    }
+    else if (TXT_MAINTEXT == m_nTextTyp && rEndNode.StartOfSectionNode()->IsTableNode())
         // End node of a table: see if a section break should be written after the table.
         AttrOutput().SectionBreaks(rEndNode);
 }