craiglabenz · May 8, 2022 15:36
diff --git a/models.py b/models.py
 from django.db import models


 class MyModelManager(models.Manager):
    
    # A few notes here:
    #
    #   1.  I add this method for its type-hinted return type. This allows me to
    #       later write "MyModel.objects.for_user(user=user).some_other_queryset_method()"
    #       and have the linter agree with me that it will work.
    #   2.  Ultimately, I call `super().the_mirrored_method()` (in this case,
    #       obviously, `for_user`) because Django has already done the mirroring.
    #       Thus, it is safe to call super() -- the `for_user` method is waiting
    #       for me there.
    #   3.  You'll see an awkward `type: ignore` annotation on the return
    #       statement. That is terrible and I hate it, but necessary, because 
    #       I haven't found another good way to convince MyPy (and by extension,
    #       Pylance) that the Manager method returns QuerySet instances. If I
    #       didn't need that `# type: ignore` comment, then I wouldn't need this
    #       whole method!
    def for_user(self, user: "auth.User") -> "MyModelQuerySet":
        return super().for_user(user)  # type: ignore


 class MyModelQuerySet(models.QuerySet):
    
    def for_user(self, user: "auth.User") -> "MyModelQuerySet":
        # Example pseudocode. Filters here vary, obviously.
        return self.filter(user=user)


 class MyModel(models.Model):
    
    user = models.ForeignKey("auth.User")
    # more fields
    
    # This is my recommended way to set up a Manager. I always create my
    # own Manager, even if I can't think of a reason I need it now, because
    # I usually will eventually and it's nice to have already exist.
    # And, setting it up this way correctly wires up the connection between
    # a Manager and its QuerySet, including all the method mirroring from
    # QuerySet to Manager.
    objects: MyModelManager = MyModelManager.from_queryset(MyModelQuerySet)()
    
    

 # With the above, in View code elsewhere, I can write this:
 #      MyModelManager.objects.for_user(user=request.user)
 # and everyone agrees that the code will work :)
	from django.db import models


	class MyModelManager(models.Manager):

	# A few notes here:
	#
	# 1. I add this method for its type-hinted return type. This allows me to
	# later write "MyModel.objects.for_user(user=user).some_other_queryset_method()"
	# and have the linter agree with me that it will work.
	# 2. Ultimately, I call `super().the_mirrored_method()` (in this case,
	# obviously, `for_user`) because Django has already done the mirroring.
	# Thus, it is safe to call super() -- the `for_user` method is waiting
	# for me there.
	# 3. You'll see an awkward `type: ignore` annotation on the return
	# statement. That is terrible and I hate it, but necessary, because
	# I haven't found another good way to convince MyPy (and by extension,
	# Pylance) that the Manager method returns QuerySet instances. If I
	# didn't need that `# type: ignore` comment, then I wouldn't need this
	# whole method!
	def for_user(self, user: "auth.User") -> "MyModelQuerySet":
	return super().for_user(user) # type: ignore


	class MyModelQuerySet(models.QuerySet):

	def for_user(self, user: "auth.User") -> "MyModelQuerySet":
	# Example pseudocode. Filters here vary, obviously.
	return self.filter(user=user)


	class MyModel(models.Model):

	user = models.ForeignKey("auth.User")
	# more fields

	# This is my recommended way to set up a Manager. I always create my
	# own Manager, even if I can't think of a reason I need it now, because
	# I usually will eventually and it's nice to have already exist.
	# And, setting it up this way correctly wires up the connection between
	# a Manager and its QuerySet, including all the method mirroring from
	# QuerySet to Manager.
	objects: MyModelManager = MyModelManager.from_queryset(MyModelQuerySet)()



	# With the above, in View code elsewhere, I can write this:
	# MyModelManager.objects.for_user(user=request.user)
	# and everyone agrees that the code will work :)