SQLite backend raises exception on negative array indices in JSONField

[savanto]

Positive jsonfield array index queries can be constructed the usual way with kwargs (ie. Model.objects.filter(jsonfield__2=1)), while negative jsonfield array index query must be constructed using the splat operator on a dict: Model.objects.filter(**{"jsonfield__-2": 1})). When querying jsonfields in this way on the SQLite backend, the following error arises:

django.db.utils.OperationalError: bad JSON path: '$[-2]'

When constructing the query, the JSON path constructor simply appends any numerical value to the path (​https://github.com/django/django/blob/5.1.4/django/db/models/fields/json.py#L155). But the SQLite backend uses a special syntax for performing negative-indexing in jsonfields (​https://sqlite.org/json1.html#path_arguments) that is different from other backends: negative indices must be prepended by a literal # character.

[savanto]

​https://github.com/django/django/pull/19030