tdf#151094 ODT export: fix crash when linked paragraph style is deleted

If a document contains a linked paragraph-character style pair and the
paragraph style gets deleted, we crash on save.

Commit 3227975c0f42ff23d528f5ab94b4538c8af764c (sw: paragraph styles:
add doc model & UNO API for a linked character style, 2021-09-24) added
support for linked para/char styles, but it failed to get the lifecycle
correctly when it comes to deleting these styles.

Fix the dangling para/char style references by explicitly looking what
styles may refer to us and clear their references.

An alternative would be to clear the "link" pointer of our own "link"
pointer only, but broken documents may e.g. link multiple paragraph
styles to a single character style, so this is probably not enough.

(cherry picked from commit 3aff88ae021c571b6e218f6e2a0f62728bb86394)

Conflicts:
sw/qa/core/doc/doc.cxx

Change-Id: I9465d43e90cf54c3c02bffda3e7c75b52c543a65
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/141023
Tested-by: Miklos Vajna <vmiklos@collabora.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>

6 files changed, 67 insertions, 6 deletions

diff --git a/sw/inc/charfmt.hxx b/sw/inc/charfmt.hxx
index e08d2f5f3a3f..84571d26263a 100644
--- a/sw/inc/charfmt.hxx
+++ b/sw/inc/charfmt.hxx
@@ -36,10 +36,11 @@ class SW_DLLPUBLIC SwCharFormat final : public SwFormat
     {}
 
 public:
+    ~SwCharFormat();
 
     void dumpAsXml(xmlTextWriterPtr pWriter) const;
 
-    void SetLinkedParaFormat(SwTextFormatColl& rLink);
+    void SetLinkedParaFormat(SwTextFormatColl* pLink);
 
     const SwTextFormatColl* GetLinkedParaFormat() const;
 };
diff --git a/sw/inc/fmtcol.hxx b/sw/inc/fmtcol.hxx
index 1b1bd7d2e46d..be547df3d840 100644
--- a/sw/inc/fmtcol.hxx
+++ b/sw/inc/fmtcol.hxx
@@ -103,7 +103,7 @@ public:
     inline void SetNextTextFormatColl(SwTextFormatColl& rNext);
     SwTextFormatColl& GetNextTextFormatColl() const { return *mpNextTextFormatColl; }
 
-    void SetLinkedCharFormat(SwCharFormat& rLink);
+    void SetLinkedCharFormat(SwCharFormat* pLink);
 
     const SwCharFormat* GetLinkedCharFormat() const;
 
diff --git a/sw/qa/core/doc/doc.cxx b/sw/qa/core/doc/doc.cxx
index 26d02e60318b..ff006bda3faf 100644
--- a/sw/qa/core/doc/doc.cxx
+++ b/sw/qa/core/doc/doc.cxx
@@ -19,6 +19,7 @@
 #include <sfx2/viewfrm.hxx>
 #include <sfx2/dispatch.hxx>
 #include <vcl/scheduler.hxx>
+#include <comphelper/propertyvalue.hxx>
 
 #include <wrtsh.hxx>
 #include <fmtanchr.hxx>
@@ -255,6 +256,35 @@ CPPUNIT_TEST_FIXTURE(SwCoreDocTest, testContentControlDelete)
     CPPUNIT_ASSERT_EQUAL(OUString("\x0001test\x0001"), pTextNode->GetText());
 }
 
+CPPUNIT_TEST_FIXTURE(SwCoreDocTest, testLinkedStyleDelete)
+{
+    // Given a document with linked styles: myparastyle is linked to mycharstyle and vica versa:
+    createSwDoc();
+    uno::Reference<lang::XMultiServiceFactory> xFactory(mxComponent, uno::UNO_QUERY);
+    uno::Reference<beans::XPropertySet> xParaStyle(
+        xFactory->createInstance("com.sun.star.style.ParagraphStyle"), uno::UNO_QUERY);
+    uno::Reference<beans::XPropertySet> xCharStyle(
+        xFactory->createInstance("com.sun.star.style.CharacterStyle"), uno::UNO_QUERY);
+    uno::Reference<container::XNameContainer> xParaStyles(getStyles("ParagraphStyles"),
+                                                          uno::UNO_QUERY);
+    xParaStyles->insertByName("myparastyle", uno::Any(xParaStyle));
+    uno::Reference<container::XNameContainer> xCharStyles(getStyles("CharacterStyles"),
+                                                          uno::UNO_QUERY);
+    xCharStyles->insertByName("mycharstyle", uno::Any(xCharStyle));
+    xParaStyle->setPropertyValue("LinkStyle", uno::Any(OUString("mycharstyle")));
+    xCharStyle->setPropertyValue("LinkStyle", uno::Any(OUString("myparastyle")));
+
+    // When deleting the paragraph style (and only that):
+    xParaStyles->removeByName("myparastyle");
+
+    // Then make sure we don't crash on save:
+    uno::Reference<frame::XStorable> xStorable(mxComponent, uno::UNO_QUERY);
+    uno::Sequence<beans::PropertyValue> aArgs = {
+        comphelper::makePropertyValue("FilterName", OUString("writer8")),
+    };
+    xStorable->storeAsURL(maTempFile.GetURL(), aArgs);
+}
+
 CPPUNIT_PLUGIN_IMPLEMENT();
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sw/source/core/doc/fmtcol.cxx b/sw/source/core/doc/fmtcol.cxx
index e35e523b6a92..531a35548818 100644
--- a/sw/source/core/doc/fmtcol.cxx
+++ b/sw/source/core/doc/fmtcol.cxx
@@ -114,6 +114,19 @@ SwTextFormatColl::~SwTextFormatColl()
 {
     if(m_bInSwFntCache)
         pSwFontCache->Delete( this );
+
+    if (GetDoc()->IsInDtor())
+    {
+        return;
+    }
+
+    for (const auto& pCharFormat : *GetDoc()->GetCharFormats())
+    {
+        if (pCharFormat->GetLinkedParaFormat() == this)
+        {
+            pCharFormat->SetLinkedParaFormat(nullptr);
+        }
+    }
 }
 void SwTextFormatColl::SwClientNotify(const SwModify& rModify, const SfxHint& rHint)
 {
@@ -325,7 +338,7 @@ void SwTextFormatColl::SwClientNotify(const SwModify& rModify, const SfxHint& rH
         SwFormatColl::SwClientNotify(rModify, rHint);
 }
 
-void SwTextFormatColl::SetLinkedCharFormat(SwCharFormat& rLink) { mpLinkedCharFormat = &rLink; }
+void SwTextFormatColl::SetLinkedCharFormat(SwCharFormat* pLink) { mpLinkedCharFormat = pLink; }
 
 const SwCharFormat* SwTextFormatColl::GetLinkedCharFormat() const { return mpLinkedCharFormat; }
 
diff --git a/sw/source/core/txtnode/chrfmt.cxx b/sw/source/core/txtnode/chrfmt.cxx
index d2e01640071d..11a89d6eb92d 100644
--- a/sw/source/core/txtnode/chrfmt.cxx
+++ b/sw/source/core/txtnode/chrfmt.cxx
@@ -21,6 +21,7 @@
 
 #include <charfmt.hxx>
 #include <charformats.hxx>
+#include <doc.hxx>
 
 void SwCharFormat::dumpAsXml(xmlTextWriterPtr pWriter) const
 {
@@ -38,10 +39,26 @@ void SwCharFormat::dumpAsXml(xmlTextWriterPtr pWriter) const
     (void)xmlTextWriterEndElement(pWriter);
 }
 
-void SwCharFormat::SetLinkedParaFormat(SwTextFormatColl& rLink) { mpLinkedParaFormat = &rLink; }
+void SwCharFormat::SetLinkedParaFormat(SwTextFormatColl* pLink) { mpLinkedParaFormat = pLink; }
 
 const SwTextFormatColl* SwCharFormat::GetLinkedParaFormat() const { return mpLinkedParaFormat; }
 
+SwCharFormat::~SwCharFormat()
+{
+    if (GetDoc()->IsInDtor())
+    {
+        return;
+    }
+
+    for (const auto& pTextFormat : *GetDoc()->GetTextFormatColls())
+    {
+        if (pTextFormat->GetLinkedCharFormat() == this)
+        {
+            pTextFormat->SetLinkedCharFormat(nullptr);
+        }
+    }
+}
+
 void SwCharFormats::dumpAsXml(xmlTextWriterPtr pWriter) const
 {
     (void)xmlTextWriterStartElement(pWriter, BAD_CAST("SwCharFormats"));
diff --git a/sw/source/uibase/app/docstyle.cxx b/sw/source/uibase/app/docstyle.cxx
index 8ab68590c1a9..374b3eb79ca1 100644
--- a/sw/source/uibase/app/docstyle.cxx
+++ b/sw/source/uibase/app/docstyle.cxx
@@ -745,7 +745,7 @@ void SwDocStyleSheet::SetLink(const OUString& rStr)
                 SwCharFormat* pLink = lcl_FindCharFormat(m_rDoc, rStr);
                 if (pLink)
                 {
-                    m_pColl->SetLinkedCharFormat(*pLink);
+                    m_pColl->SetLinkedCharFormat(pLink);
                 }
             }
             break;
@@ -757,7 +757,7 @@ void SwDocStyleSheet::SetLink(const OUString& rStr)
                 SwTextFormatColl* pLink = lcl_FindParaFormat(m_rDoc, rStr);
                 if (pLink)
                 {
-                    m_pCharFormat->SetLinkedParaFormat(*pLink);
+                    m_pCharFormat->SetLinkedParaFormat(pLink);
                 }
             }
             break;