`BaseDetailView` and `SingleObjectMixin` optimization.

[Davit Gachechiladze]

Hi. In BaseDetailView.get(self, request, *args, **kwargs), we have line like context = self.get_context_data(object=self.object). Why should we pass object=self.object ? It's redundant (IMHO).

class SingleObjectMixin(ContextMixin):

    def get_context_data(self, **kwargs):
        """Insert the single object into the context dict."""
        context = {}
        if self.object:
            context['object'] = self.object
            context_object_name = self.get_context_object_name(self.object)
            if context_object_name:
                context[context_object_name] = self.object
        context.update(kwargs)
        return super().get_context_data(**context)

class BaseDetailView(SingleObjectMixin, View):
    """A base view for displaying a single object."""
    def get(self, request, *args, **kwargs):
        self.object = self.get_object()
        context = self.get_context_data(object=self.object)
        return self.render_to_response(context)

I think, it's better idea to implement SingleObjectMixin.get_context_data and BaseDetailView.get like this. Code below

class SingleObjectMixin(ContextMixin):
    def get_context_data(self, *, object=None, **kwargs):
        """Insert the single object into the context dict."""
        object = object if object is not None else self.object
        context = {}
        if object:
            context['object'] = object
            context_object_name = self.get_context_object_name(object)
            if context_object_name:
                context[context_object_name] = object
        context.update(kwargs)
        return super().get_context_data(**context)

class BaseDetailView(SingleObjectMixin, View):
    """A base view for displaying a single object."""
    def get(self, request, *args, **kwargs):
        self.object = self.get_object()
        context = self.get_context_data()
        return self.render_to_response(context)

Also, SingleObjectMixin will be implemented in a same fashion as MultipleObjectMixin is this moment.

​https://github.com/gachdavit/django/pull/1