Fix #409 Leak of global user vars

(cherry picked from commit 33b71aae0a117707ae3e988a373f9782efb1fbc3)

src/searchd.cpp

@@ -477,7 +477,7 @@ enum Uservar_e
 struct Uservar_t
 {
 	Uservar_e			m_eType { USERVAR_INT_SET };
-	UservarIntSet_c *	m_pVal = nullptr;
+	CSphRefcountedPtr<UservarIntSet_c>	m_pVal;
 };
 
 static CSphMutex					g_tUservarsMutex;
@@ -15899,8 +15899,6 @@ static void UservarAdd ( const CSphString & sName, CSphVector<SphAttr_t> & dVal
 		// from here, the old value becomes nameless, though
 		assert ( pVar->m_eType==USERVAR_INT_SET );
 		assert ( pVar->m_pVal );
-		pVar->m_pVal->Release();
-		pVar->m_pVal = nullptr;
 	} else
 	{
 		// create a shiny new variable
@@ -15911,9 +15909,8 @@ static void UservarAdd ( const CSphString & sName, CSphVector<SphAttr_t> & dVal
 
 	// swap in the new value
 	assert ( pVar );
-	assert ( !pVar->m_pVal );
 	pVar->m_eType = USERVAR_INT_SET;
-	pVar->m_pVal = new UservarIntSet_c();
+	pVar->m_pVal = new UservarIntSet_c(); // previous will be auto-released here
 	pVar->m_pVal->SwapData ( dVal );
 }
 
 struct NamedRefVectorPair_t
 {
 	CSphString			m_sName;
-	UservarIntSet_c *	m_pVal;
+	CSphRefcountedPtr<UservarIntSet_c>	m_pVal;
 };
 
 
 				NamedRefVectorPair_t &tPair = dUservars.Add ();
 				tPair.m_sName = g_hUservars.IterateGetKey ();
 				tPair.m_pVal = g_hUservars.IterateGet ().m_pVal;
-				tPair.m_pVal->AddRef ();
 			}
 		}
 		dUservars.Sort ( bind ( &NamedRefVectorPair_t::m_sName ) );
 			tWriter.PutBytes ( sTail, sizeof ( sTail )-1 );
 		}
 
-		// release all locked uservars
-		ARRAY_FOREACH ( i, dUservars )
-			dUservars[i].m_pVal->Release();
-
 		/////////////////////////////////
 		// writing done, flip the burger
 		/////////////////////////////////

src/sphinxint.h

@@ -1709,7 +1709,6 @@ uint64_t sphGetSettingsFNV ( const CSphIndexSettings & tSettings );
 /// value container for the intset uservar type
 class UservarIntSet_c : public CSphVector<SphAttr_t>, public ISphRefcountedMT
 {
-	~UservarIntSet_c() = default;
 };
 
 extern UservarIntSet_c * ( *g_pUservarsHook )( const CSphString & sUservar );