sw: fix recursive SwTextInputField::LockNotifyContentChange

(related: tdf#123968)

The assertion added in commit 742baabb
is triggered during ODF import of import fields associated with user
field types; there is a 3 level recursion of the SwUserFieldType for one
variable calling the SwInputFieldType calling SwUserFieldType of another
variable...

Change-Id: I54fc56733c7375cfdb6439b02cf21c4d852c2b4c
Reviewed-on: https://gerrit.libreoffice.org/70768
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>

sw/inc/txtfld.hxx

@@ -87,7 +87,7 @@ public:
 
     virtual ~SwTextInputField() override;
 
-    void LockNotifyContentChange();
+    bool LockNotifyContentChange();
     void UnlockNotifyContentChange();
     virtual void NotifyContentChange( SwFormatField& rFormatField ) override;
 

sw/source/core/doc/DocumentFieldsManager.cxx

@@ -1275,7 +1275,9 @@ void DocumentFieldsManager::UpdateExpFieldsImpl(
                     : dynamic_cast<SwTextInputField *>(pTextField));
             if (pInputField)
             {
-                pInputField->LockNotifyContentChange();
+                bool const tmp = pInputField->LockNotifyContentChange();
+                (void) tmp;
+                assert(tmp && "should not be locked here?");
             }
             ::comphelper::ScopeGuard g([pInputField]()
                 {

sw/source/core/fields/expfld.cxx

@@ -1261,23 +1261,29 @@ void SwInputField::applyFieldContent( const OUString& rNewFieldContent )
         if( pUserTyp )
         {
             pUserTyp->SetContent( rNewFieldContent );
-
-            // trigger update of the corresponding User Fields and other related Input Fields
-            if ( GetFormatField() != nullptr )
+            if (!pUserTyp->IsModifyLocked())
             {
-                SwTextInputField* pTextInputField = dynamic_cast< SwTextInputField* >(GetFormatField()->GetTextField());
-                if ( pTextInputField != nullptr )
+                // trigger update of the corresponding User Fields and other
+                // related Input Fields
+                bool bUnlock(false);
+                if (GetFormatField() != nullptr)
                 {
-                    pTextInputField->LockNotifyContentChange();
+                    SwTextInputField *const pTextInputField =
+                        dynamic_cast<SwTextInputField*>(GetFormatField()->GetTextField());
+                    if (pTextInputField != nullptr)
+                    {
+                        bUnlock = pTextInputField->LockNotifyContentChange();
+                    }
                 }
-            }
-            pUserTyp->UpdateFields();
-            if ( GetFormatField() != nullptr )
-            {
-                SwTextInputField* pTextInputField = dynamic_cast< SwTextInputField* >(GetFormatField()->GetTextField());
-                if ( pTextInputField != nullptr )
+                pUserTyp->UpdateFields();
+                if (bUnlock)
                 {
-                    pTextInputField->UnlockNotifyContentChange();
+                    SwTextInputField *const pTextInputField =
+                        dynamic_cast<SwTextInputField*>(GetFormatField()->GetTextField());
+                    if (pTextInputField != nullptr)
+                    {
+                        pTextInputField->UnlockNotifyContentChange();
+                    }
                 }
             }
         }

sw/source/core/txtnode/atrfld.cxx

@@ -557,10 +557,14 @@ SwTextInputField::~SwTextInputField()
 {
 }
 
-void SwTextInputField::LockNotifyContentChange()
+bool SwTextInputField::LockNotifyContentChange()
 {
-    assert(!m_bLockNotifyContentChange); // not nestable
+    if (m_bLockNotifyContentChange)
+    {
+        return false;
+    }
     m_bLockNotifyContentChange = true;
+    return true;
 }
 
 void SwTextInputField::UnlockNotifyContentChange()