Right, but the better way to actually write this is something like

  entry = Entry.objects.filter(blog__id=1, 
  entry_number=1).first()
  if entry is None:
    # deal with does not exist

Maybe it's my scala/Java background shining through, but we are big Django users and we ban the "catch exceptions as standard" workflow, because there is almost always a cleaner way...

This fails to raise an error if there is more than one object matching the given filters

Presumably entry_number is unique_together with blog_id. Otherwise the original code is also not handling the MultipleObjectsReturned exception.

Generally speaking, I tend toward the cleanest code being:

    blog = Blog.objects.get(id=1)
    entry = blog.entry_set.filter(entry_number=1).first()
    if entry is None:
        handle_missing_entry()
    handle_entry(entry)

But it does suffer from having the extra DB query in there, which may or may not be helpful, depending on the surrounding code (and whether or not you'll be using the blog instance anywhere else).

> Right, but the better way to actually write this is something like

Maybe for some cases, but it does not do the exact same thing, see the comment here: https://stackoverflow.com/a/29455777/1598080

And if we are talking about idiomatic, I think it is maybe a stretch to count this as idiomatic for Python, but given it is documented for Django I think it is fair to call it idiomatic for Django.

I wouldn't make it an if statement unless it's going to be a part of the standard flow. I think the catchphrase is "leap before you look". Though your right that a single query is better.

Honestly, I normally just use get and let the exception fly. If it's a celery task I'll see the stack trace in flower, or right in the output if it's dev with debug on. Then I would go out of my way to make sure there was never a circumstance where a user requests something that doesn't exist.

That is the sort of method that I prefer if it's available. I'm a C# dev so this way also feels far cleaner to me.

What are you suggesting is better about that way? More readable?