MongoEngine / MongoEngine/mongoengine
Method aggregate do not honor _none flag
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- Dominant language
- Python
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- Merged PRs (30d)
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Description
This code:
Some.objects.filter(id=some_id).none().aggregate(...)
Will produce an aggregation with {$match: some_id} despite none().
This behaviour is undesirable, because we can have chain filtering and on some stage we can decide that whole queryset should be empty.
I've also noticed that sum and average do not honour _none flag as well.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in mongoengine/queryset/base.py, especially the aggregate, sum, and average entry points; the issue links directly to the latter two. Trace how the queryset’s _none state is handled, then verify that all three methods preserve empty-queryset behavior rather than applying earlier filters.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- mongodb, python
- Domain
- database
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100