Why django ManytoManyFied don't save some models?

Below is my models.py.

class Report(models.Model):
    company_name = models.CharField(max_length = 40, default = "-")
    favorite = models.ManyToManyField(settings.AUTH_USER_MODEL,
        through='Fav', related_name='favorite_reports') 

    def __str__(self):
        return self.company_name
class Fav(models.Model) :
    
    report = models.ForeignKey(Report, on_delete=models.CASCADE)
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE,
        related_name='favs_users')

    class Meta:
        unique_together = ('report', 'user')

    def __str__(self) :
        return '%s likes %s'%(self.user.username, self.report.company_name[:10])

Below is views.py

    def post(self, request, pk) :  
        t = Report.objects.get(id = pk)
        fav = Fav(user=request.user, report=t)
        try:
            fav.save()  # In case of duplicate key
            print(request.user.favorite_reports) #home.Report.None 
            print('t =', t.favorite) # t = auth.User.None
            print('fav =',fav.report, fav.user) # fav = untitle hello1
            print('uesr =',request.user, request.user.favorite_reports,request.user.favs_users) #uesr = hello1 home.Report.None home.Fav.None
        except IntegrityError as e:
            pass
        return redirect('home:homepage')

I want show different button color to user whether user fav some report or not. So I checked request.user.favorite_reports and request.user.favs_users after I save Fav but it return home.Report.None home.Fav.None

But When I print fav.report, fav.user It returns well. Why this happened?

How can I check user Fav some report in template?

like {% if report.company_name in user.favorite_reports %} But It dosen’t works.

>Solution :

You should call request.user.favorite_reports.all()