Opened 6 months ago

Last modified 6 months ago

#36385 assigned Cleanup/optimization

Simplify implementation of filtering in QuerySet.

Reported by: Nick Pope Owned by: Nick Pope
Component: Database layer (models, ORM) Version: dev
Severity: Normal Keywords:
Cc: Simon Charette Triage Stage: Accepted
Has patch: yes Needs documentation: yes
Needs tests: no Patch needs improvement: yes
Easy pickings: no UI/UX: no

Description

Some of the code for filtering QuerySet is overly complex which makes it hard to follow:

  • Methods that are nearly identical, e.g. QuerySet._clone() vs QuerySet._chain() and Query.clone() vs Query.chain()
    • These used to do more, but now are not significantly different such that they're worth keeping separate.
  • Private API like Queryset.complex_filter() which exists for a specific case but can be handled using public APIs
  • Flags such as _defer_next_filter and _sticky_filter that affect the next call to QuerySet.filter()
  • Passing around deconstructed pieces instead of building a Q() object as early as possible
  • Not using the klass argument to Query.chain() and altering __class__ manually

We should be able to simplify this, removing a number of flag attributes and methods in the process.

Change History (3)

comment:1 by Nick Pope, 6 months ago

Has patch: set

​PR

comment:2 by Natalia Bidart, 6 months ago

Cc: Simon Charette added
Triage Stage: Unreviewed → Accepted

Hello Nick, thank you for the ticket and carefully crafted PR. After a quick look this seems like a positive cleanup, so I'm accepting pending feedback from Simon in the PR.

comment:3 by Simon Charette, 6 months ago

Needs documentation: set
Patch needs improvement: set

The patch itself is great and a very welcomed cleanup but I suggest we defer the complete removal of the internal methods with deprecation shims and mentions in the release notes as it will inevitably break code out there.

Marking as needing improvement for this reason.

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