sw ChangesInMargin: fix crash at Undo of deletion of paragraph break

Deletion of the paragraph break by pressing Delete results
an empty hidden redline, too, which caused a problem during Undo
(if there were other tracked redlines, too).

Change-Id: I64968688688be72d4e501631244b4c57ab634585
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107830
Tested-by: Jenkins
Reviewed-by: László Németh <nemeth@numbertext.org>
(cherry picked from commit 172373c4a2c4a66b8abbe26dbe07fd621c971ed0)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107899

2 files changed, 43 insertions, 2 deletions

diff --git a/sw/qa/extras/uiwriter/uiwriter2.cxx b/sw/qa/extras/uiwriter/uiwriter2.cxx
index c3d4d71d6b5c..496b9b8602bc 100644
--- a/sw/qa/extras/uiwriter/uiwriter2.cxx
+++ b/sw/qa/extras/uiwriter/uiwriter2.cxx
@@ -2084,6 +2084,47 @@ CPPUNIT_TEST_FIXTURE(SwUiWriterTest2, testTdf137771)
     CPPUNIT_ASSERT(!pWrtShell->GetViewOptions()->IsShowChangesInMargin());
 }
 
+CPPUNIT_TEST_FIXTURE(SwUiWriterTest2, testJoinParaChangesInMargin)
+{
+    load(DATA_DIRECTORY, "tdf54819.fodt");
+
+    SwXTextDocument* pTextDoc = dynamic_cast<SwXTextDocument*>(mxComponent.get());
+    CPPUNIT_ASSERT(pTextDoc);
+
+    // switch on "Show changes in margin" mode
+    dispatchCommand(mxComponent, ".uno:ShowChangesInMargin", {});
+
+    SwWrtShell* const pWrtShell = pTextDoc->GetDocShell()->GetWrtShell();
+    CPPUNIT_ASSERT(pWrtShell->GetViewOptions()->IsShowChangesInMargin());
+
+    // turn on red-lining and show changes
+    SwDoc* pDoc = pWrtShell->GetDoc();
+    pDoc->getIDocumentRedlineAccess().SetRedlineFlags(RedlineFlags::On | RedlineFlags::ShowInsert
+                                                      | RedlineFlags::ShowDelete);
+    CPPUNIT_ASSERT_MESSAGE("redlining should be on",
+                           pDoc->getIDocumentRedlineAccess().IsRedlineOn());
+    CPPUNIT_ASSERT_MESSAGE(
+        "redlines should be visible",
+        IDocumentRedlineAccess::IsShowChanges(pDoc->getIDocumentRedlineAccess().GetRedlineFlags()));
+
+    // delete a character and the paragraph break at the end of the paragraph
+    dispatchCommand(mxComponent, ".uno:GotoEndOfPara", {});
+    pWrtShell->Left(CRSR_SKIP_CHARS, /*bSelect=*/true, 1, /*bBasicCall=*/false);
+    dispatchCommand(mxComponent, ".uno:Delete", {});
+    dispatchCommand(mxComponent, ".uno:Delete", {});
+    CPPUNIT_ASSERT_EQUAL(OUString("Lorem ipsudolor sit amet."), getParagraph(1)->getString());
+
+    // Undo
+    dispatchCommand(mxComponent, ".uno:Undo", {});
+    // this would crash due to bad redline range
+    dispatchCommand(mxComponent, ".uno:Undo", {});
+    CPPUNIT_ASSERT_EQUAL(OUString("Lorem ipsum"), getParagraph(1)->getString());
+
+    // switch off "Show changes in margin" mode
+    dispatchCommand(mxComponent, ".uno:ShowChangesInMargin", {});
+    CPPUNIT_ASSERT(!pWrtShell->GetViewOptions()->IsShowChangesInMargin());
+}
+
 CPPUNIT_TEST_FIXTURE(SwUiWriterTest2, testTdf138479)
 {
     SwDoc* const pDoc = createDoc();
diff --git a/sw/source/core/undo/unredln.cxx b/sw/source/core/undo/unredln.cxx
index 93d0b0d393a2..0e0d89765beb 100644
--- a/sw/source/core/undo/unredln.cxx
+++ b/sw/source/core/undo/unredln.cxx
@@ -107,7 +107,7 @@ void SwUndoRedline::UndoImpl(::sw::UndoRedoContext & rContext)
             for( SwRedlineTable::size_type n = 1; n < rTable.size(); ++n )
             {
                 SwRangeRedline *pRed(rTable[n]);
-                if ( pRedline->GetId() < pRed->GetId() && pRed->GetId() < nMaxId )
+                if ( !pRed->HasMark() && pRedline->GetId() < pRed->GetId() && pRed->GetId() < nMaxId )
                 {
                     nCurRedlinePos = n;
                     pRedline = pRed;
@@ -116,7 +116,7 @@ void SwUndoRedline::UndoImpl(::sw::UndoRedoContext & rContext)
 
             nMaxId = pRedline->GetId();
 
-            if ( !pRedline->IsVisible() )
+            if ( !pRedline->IsVisible() && !pRedline->HasMark() )
             {
                 // set it visible
                 pRedline->Show(0, rTable.GetPos(pRedline), /*bForced=*/true);