Fix potential dangling iterator

BUG: 290533

ChangeLog

@@ -16,6 +16,7 @@ Version 2.6-Beta 1
       "1.2 GB free" is shown instead of "85% used"; thicker capacity bar.
 
   BUGFIXES:
+    * Fix rare APG solver crash. (BR 290533)
     * Compilations are handled more consistently on iPods. (BR 232072)
 
 Version 2.5

src/playlistgenerator/ConstraintSolver.cpp

@@ -253,6 +253,8 @@ APG::ConstraintSolver::select_population( APG::ConstraintSolver::Population& pop
     while ( it != population.end() ) {
         if ( it.key() == best ) {
             ++it;// Always keep the best solution, no matter how bad it is
+            if ( it == population.end() )
+                break;
         }
         
         if ( select( it.value() ) ) {