Add support for chaining `in_bulk()` after `values()`/`values_list()`

[jacobtylerwalls]

Code of Conduct

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Feature Description

Add support for chaining QuerySet.in_bulk() after .values()/.values_list().

This was recently updated to raise TypeError when attempted.

Problem

in_bulk() is useful for more than just aliasing {obj.pk: obj for obj in qs}, since it can apply a filter clause based on an id_list input, and batch according to the database's parameter limit. That limit can be cumbersome to calculate, especially after support for composite pk's in Django 5.2.

For instance, in the model field fetch modes feature, the implementation of fetch_peers() issues a .filter() against a potentially large set of pk's. It would be convenient to leverage .in_bulk(id_list=pks) to do this filtering in a parameter-limit-safe way, but the queryset is a values() queryset, since we don't want to materialize the entire objects, so we... can't.

See comment.

Request or proposal

proposal

Additional Details

No response

Implementation Suggestions

There's a draft implementation for at least values() by @john-parton here .

[github-actions]

Thank you jacobtylerwalls for sharing your idea! We have a lot of them so please be patient. You can see the current queue here.

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[LilyFirefly]

Since we want to use this in Django itself and there's a PR already being worked on I'm moving this to in progress.

[adamchainz]

Ticket: https://code.djangoproject.com/ticket/36605

PR: django/django#19842