Bug 1668926 - fix resource leak in nsBayesianFilter::​classifyMessage. r=benc

CID 1494443 Resource leak

The system resource will not be reclaimed and reused, reducing the future availability of the resource.
In nsBayesianFilter::​classifyMessage(Tokenizer &, nsTSubstring<char> const &, nsTArray<unsigned int> &, nsTArray<unsigned int> &, nsIJunkMailClassificationListener *, nsIMsgTraitClassificationListener *, nsIMsgTraitDetailListener *): Leak of memory or pointers to system resources

Differential Revision: https://phabricator.services.mozilla.com/D132777

--HG--
extra : rebase_source : fa28ca85b1e484497822eb8775b51b2e8d9d5778

mailnews/extensions/bayesian-spam-filter/nsBayesianFilter.cpp

@@ -1421,6 +1421,10 @@ void nsBayesianFilter::classifyMessage(
     nsIJunkMailClassificationListener* listener,
     nsIMsgTraitClassificationListener* aTraitListener,
     nsIMsgTraitDetailListener* aDetailListener) {
+  if (aProTraits.Length() != aAntiTraits.Length()) {
+    NS_ERROR("Each Pro trait needs a matching Anti trait");
+    return;
+  }
   Token* tokens = tokenizer.copyTokens();
   uint32_t tokenCount;
   if (!tokens) {
@@ -1432,11 +1436,6 @@ void nsBayesianFilter::classifyMessage(
     tokenCount = tokenizer.countTokens();
   }
 
-  if (aProTraits.Length() != aAntiTraits.Length()) {
-    NS_ERROR("Each Pro trait needs a matching Anti trait");
-    return;
-  }
-
   /* this part is similar to the Graham algorithm with some adjustments. */
   uint32_t traitCount = aProTraits.Length();