Edit popup in model 'change' page results in a not found if the foreign key model contains a space

[Mathis]

In the 'change' page of the admin panel, if we try to edit a model linked by ForeignKey which contains a space in the 'to_field' property, the result is a 'not found page'.

Example:

class Media(models.Model):
    author = models.ForeignKey('Author', verbose_name="Author", on_delete=models.SET_NULL, to_field="name", default="Unknown", null=True)

In this case, if the Author.name contains a space, the generated URL to edit this author will be: ​https://domain.com/admin/web_app/author/Spaced%20Name/change/?_to_field=name&_popup=1

The result is (in french with a translation, sorry):

The strange thing is that I can't reproduce this behaviour in my local version.

[Mariusz Felisiak]

I also cannot reproduce this issue with spaces, but it's possible with other keys, e.g. _40. I believe we can close this as a duplicate of #30386, which is due to the fact that foreign key widgets don't quote keys.