tdf#90046: RTF import: ensure that a run is started before \footnote

Avoids crashing with empty context stacks.

Change-Id: I0ee8b457fdbb19b55f5c15876b7253680cde6e23
(cherry picked from commit a61fd02c)
Reviewed-on: https://gerrit.libreoffice.org/17334Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/qa/extras/rtfimport/data/tdf90046.rtf

+{\rtf1\ansi\deflang1035
+{\fonttbl {\f0\fcharset0 Arial;} }
+
+\pard\ltrpar\uc1\lang1035
+{\super \chftn
+{\footnote {\pard\plain\super \chftn }{\plain\ltrch\f0 \fs18 \cf1 \uc0\u77 \u97 }
+}}
+}

sw/qa/extras/rtfimport/rtfimport.cxx

@@ -2173,6 +2173,15 @@ DECLARE_RTFIMPORT_TEST(testFdo85889pca, "fdo85889-pca.rtf")
     CPPUNIT_ASSERT_EQUAL(aExpected, xTextRange->getString());
 }
 
+DECLARE_RTFIMPORT_TEST(testTdf90046, "tdf90046.rtf")
+{
+    // this was crashing on importing the footnote
+    uno::Reference<text::XFootnotesSupplier> xFootnotesSupplier(mxComponent, uno::UNO_QUERY);
+    uno::Reference<container::XIndexAccess> xFootnotes(xFootnotesSupplier->getFootnotes(), uno::UNO_QUERY);
+    uno::Reference<text::XTextRange> xTextRange(xFootnotes->getByIndex(0), uno::UNO_QUERY);
+    CPPUNIT_ASSERT_EQUAL(OUString("Ma"), xTextRange->getString());
+}
+
 DECLARE_RTFIMPORT_TEST(testFdo85889mac, "fdo85889-mac.rtf")
 {
     uno::Reference<text::XTextRange> xTextRange = getRun(getParagraph(1), 1);

writerfilter/source/rtftok/rtfdocumentimpl.cxx

@@ -1676,6 +1676,7 @@ RTFError RTFDocumentImpl::dispatchDestination(RTFKeyword nKeyword)
             }
             break;
         case RTF_FOOTNOTE:
+            checkFirstRun();
             if (!m_pSuperstream)
             {
                 Id nId = NS_ooxml::LN_footnote;