svx, sd, sw: GetPoolDefaultItem() can actually return nullptr

...if you call ResetPoolDefaultItem() first. Crash found by Varun Dhall.

Change-Id: I409484c172fb5843270aee2425844076a008b4df

sd/source/core/stlpool.cxx

@@ -1127,7 +1127,10 @@ void SdStyleSheetPool::PutNumBulletItem( SfxStyleSheetBase* pSheet,
         case HID_PSEUDOSHEET_SUBTITLE :
         {
             // Subtitle template
-            SvxNumRule* pDefaultRule = static_cast<const SvxNumBulletItem*>( rSet.GetPool()->GetSecondaryPool()->GetPoolDefaultItem(EE_PARA_NUMBULLET))->GetNumRule();
+            SvxNumBulletItem const*const pItem(
+                static_cast<const SvxNumBulletItem*>(
+                    rSet.GetPool()->GetSecondaryPool()->GetPoolDefaultItem(EE_PARA_NUMBULLET)));
+            SvxNumRule *const pDefaultRule = (pItem) ? pItem->GetNumRule() : nullptr;
             DBG_ASSERT( pDefaultRule, "Where is my default template? [CL]" );
 
             if(pDefaultRule)

svx/source/unodraw/unopool.cxx

@@ -321,7 +321,10 @@ uno::Any SvxUnoDrawPool::_getPropertyDefault( const comphelper::PropertyMapEntry
     SfxItemPool* pPool = getModelPool( true );
     const sal_uInt16 nWhich = pPool->GetWhich( (sal_uInt16)pEntry->mnHandle );
     const SfxPoolItem *pItem = pPool->GetPoolDefaultItem ( nWhich );
+    if (pItem)
+    {
         pItem->QueryValue( aAny, pEntry->mnMemberId );
+    }
 
     return aAny;
 }

sw/source/core/unocore/SwXTextDefaults.cxx

@@ -219,8 +219,11 @@ Any SAL_CALL SwXTextDefaults::getPropertyDefault( const OUString& rPropertyName
         throw UnknownPropertyException( "Unknown property: " + rPropertyName, static_cast < cppu::OWeakObject * > ( this ) );
     Any aRet;
     SfxItemPool& rSet (m_pDoc->GetAttrPool());
-    const SfxPoolItem *pItem = rSet.GetPoolDefaultItem ( pMap->nWID );
+    SfxPoolItem const*const pItem = rSet.GetPoolDefaultItem(pMap->nWID);
+    if (pItem)
+    {
         pItem->QueryValue( aRet, pMap->nMemberId );
+    }
     return aRet;
 }