tdf#148683 sw: fix crash on deleting text with redlining enabled, but hidden

Regression from commit 32902f66e7749b2d06d13f50416be5323a0c0ea9
(sw_redlinehide: make layout based Show/Hide mode the default,
2018-11-30), deleting some text in the middle of the paragraph with the
bugdoc results in an assertion failure in the SwDrawTextInfo ctor.

Normally this doesn't happen on text deletion as we already have a
mechanism for truncating no longer needed lines in
SwTextFrame::Format_(), though that only checks the length of the
current line.

Fix the problem by extending this mechanism to also check the remaining
lines: if change tracking is on and the total of all line lengths is
more than the string length of the text frame, then time to
re-calculate.

It seems this is not needed in practice when redlining is disabled,
though we might want to enable this for the non-redline case as well in
the future.

(cherry picked from commit 515bf5d4afa3a8ed413fd6f17f66fa98b6dbf29e)

Change-Id: Iede03e11daceb3c2b614a301e21560b075a60c01
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/133684
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
Tested-by: Jenkins

3 files changed, 62 insertions, 1 deletions

diff --git a/sw/CppunitTest_sw_core_text.mk b/sw/CppunitTest_sw_core_text.mk
index 19d8cd422edc..c3025f007a9a 100644
--- a/sw/CppunitTest_sw_core_text.mk
+++ b/sw/CppunitTest_sw_core_text.mk
@@ -21,6 +21,7 @@ $(eval $(call gb_CppunitTest_use_libraries,sw_core_text, \
     comphelper \
     cppu \
     cppuhelper \
+    editeng \
     sal \
     sfx \
     svl \
diff --git a/sw/qa/core/text/text.cxx b/sw/qa/core/text/text.cxx
index 845eb2fd5b15..f8a30dfcf8d4 100644
--- a/sw/qa/core/text/text.cxx
+++ b/sw/qa/core/text/text.cxx
@@ -24,12 +24,13 @@
 #include <IDocumentLayoutAccess.hxx>
 #include <rootfrm.hxx>
 #include <txtfrm.hxx>
-
 #include <porlay.hxx>
 #include <pormulti.hxx>
 #include <sortedobjs.hxx>
 #include <anchoredobject.hxx>
 #include <fmtcntnt.hxx>
+#include <fmtfsize.hxx>
+#include <IDocumentRedlineAccess.hxx>
 
 constexpr OUStringLiteral DATA_DIRECTORY = u"/sw/qa/core/text/data/";
 
@@ -278,6 +279,47 @@ CPPUNIT_TEST_FIXTURE(SwCoreTextTest, testAsCharImageDocModelFromViewPoint)
     CPPUNIT_ASSERT_EQUAL(aGraphicNode, pShellCursor->GetMark()->nNode);
 }
 
+CPPUNIT_TEST_FIXTURE(SwCoreTextTest, testRedlineDelete)
+{
+    // Given a document with A4 paper size, some text, redlining on, but hidden:
+    SwDoc* pDoc = createSwDoc();
+    SwDocShell* pDocShell = pDoc->GetDocShell();
+    SwWrtShell* pWrtShell = pDocShell->GetWrtShell();
+    {
+        // Set page size to A4.
+        size_t nCurIdx = pWrtShell->GetCurPageDesc();
+        SwPageDesc aPageDesc(pWrtShell->GetPageDesc(nCurIdx));
+        SwFrameFormat& rMaster = aPageDesc.GetMaster();
+        SwFormatFrameSize aSize(SwFrameSize::Fixed);
+        aSize.SetSize(Size(11906, 16838));
+        rMaster.SetFormatAttr(aSize);
+        pWrtShell->ChgPageDesc(nCurIdx, aPageDesc);
+    }
+    OUString aBefore("aaaaaaaaa aaaaaaaaaa aa aa aa ");
+    OUString aDelete("delete eeeeeeeeeee ee eeeeeeeeeee ee eeeeee");
+    pWrtShell->Insert(aBefore + " " + aDelete
+                      + " zz zzz zzzzzzzzz zzz zzzz zzzz zzzzzzzzz zzzzzz zzz zzzzzzzzzzz zzz");
+    // Enable redlining.
+    pDocShell->SetChangeRecording(/*bActivate=*/true);
+    // Hide redlining.
+    pWrtShell->StartAllAction();
+    pWrtShell->GetLayout()->SetHideRedlines(true);
+    pWrtShell->EndAllAction();
+
+    // When deleting content in the middle of the paragraph:
+    pWrtShell->SttEndDoc(/*bStt=*/true);
+    pWrtShell->Right(CRSR_SKIP_CHARS, /*bSelect=*/false, /*nCount=*/aBefore.getLength(),
+                     /*bBasicCall=*/false);
+    pWrtShell->Right(CRSR_SKIP_CHARS, /*bSelect=*/true, /*nCount=*/aDelete.getLength(),
+                     /*bBasicCall=*/false);
+    // Without the accompanying fix in place, this test would have crashed:
+    pWrtShell->Delete();
+
+    // Then make sure that the redline is created:
+    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(1),
+                         pDoc->getIDocumentRedlineAccess().GetRedlineTable().size());
+}
+
 CPPUNIT_PLUGIN_IMPLEMENT();
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sw/source/core/text/frmform.cxx b/sw/source/core/text/frmform.cxx
index 2eba32cdef55..9837d3df6c2f 100644
--- a/sw/source/core/text/frmform.cxx
+++ b/sw/source/core/text/frmform.cxx
@@ -1611,9 +1611,27 @@ void SwTextFrame::Format_( SwTextFormatter &rLine, SwTextFormatInfo &rInf,
         // If we're finished formatting the text and we still
         // have other line objects left, these are superfluous
         // now because the text has gotten shorter.
+        bool bTruncLines = false;
         if( rLine.GetStart() + rLine.GetLength() >= nStrLen &&
             rLine.GetCurr()->GetNext() )
         {
+            bTruncLines = true;
+        }
+        else if (GetMergedPara() && rLine.GetCurr()->GetNext())
+        {
+            // We can also have superfluous lines with redlining in case the current line is shorter
+            // than the text length, but the total length of lines is still more than expected.
+            // Truncate in this case as well.
+            TextFrameIndex nLen(0);
+            for (const SwLineLayout* pLine = pPara; pLine; pLine = pLine->GetNext())
+            {
+                nLen += pLine->GetLen();
+            }
+            bTruncLines = nLen > nStrLen;
+        }
+
+        if (bTruncLines)
+        {
             rLine.TruncLines();
             rLine.SetTruncLines( true );
         }