message: replace use of data member fStack by direct access to stack pointer via instance call, this should solve the failing tests
diff: @@ -310,10 +310,11 @@ void AliGenExtFile::Generate()
  consecutiveDiscardedEvents=0;
  }
  + AliStack *stack = AliRunLoader::Instance()->Stack();
  +
  // Base multiplicity trigger
  if(fSetMultTrig){
  AliInfo(Form("mult cut : %i",fMultCut));
  - AliStack *stack = AliRunLoader::Instance()->Stack();
  if(!MultiplicityTrigger(stack)){
  stack->Clean();
  consecutiveDiscardedEvents++;
  @@ -350,7 +351,7 @@ void AliGenExtFile::Generate()
  continue;
  }
  Int_t inew = selector.newId(iold);
  - TParticle* particle = fStack->Particle(inew);
  + TParticle* particle = stack->Particle(inew);
  if (!particle) {
  AliErrorStream() << "Could not find particle " << inew << std::endl;
  continue;
  @@ -363,8 +364,8 @@ void AliGenExtFile::Generate()
  TParticle* parent1 = nullptr;
  TParticle* parent2 = nullptr;
  - if (iparent1 >= 0) parent1 = fStack->Particle(iparent1);
  - if (iparent2 >= 0) parent2 = fStack->Particle(iparent2);
  + if (iparent1 >= 0) parent1 = stack->Particle(iparent1);
  + if (iparent2 >= 0) parent2 = stack->Particle(iparent2);
  if (parent1 && !parent2) {
  // Only the first mother exists, nothing to be done
  