id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
35536	Incorrect represent empty list from JSONField in ChangeList	Denis Dudnik	nobody	"I have a model like this:
{{{
class HistoryEvent(models.Model):
    name = models.TextField()
    value = JSONField(blank=True, null=True)
    edit_at = models.DateTimeField(default=timezone.now)
    edit_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
}}}

I have a number of records with values like these:
1. Empty list - []
2. Empty dict - {}

I have registered ModelAdmin like this:
{{{
@admin.register(HistoryEvent)
class HistoryEventAdmin(admin.ModelAdmin):
    list_display = (""name"", ""value"")
}}}

When I open a page with data in the admin panel, I find some things:
1. Empty dict represents as a text like this""{}""
2. Empty list represents as an empty text like this"""" while I wait ""[]""

The problem could be here:
django 5.0.6
file: django/contrib/admin/utils.py

{{{
def display_for_field(value, field, empty_value_display):
    from django.contrib.admin.templatetags.admin_list import _boolean_icon

    if getattr(field, ""flatchoices"", None):
        try:
            return dict(field.flatchoices).get(value, empty_value_display)
        except TypeError:
            # Allow list-like choices.
            flatchoices = make_hashable(field.flatchoices)
            value = make_hashable(value)
            return dict(flatchoices).get(value, empty_value_display)

    # BooleanField needs special-case null-handling, so it comes before the
    # general null test.
    elif isinstance(field, models.BooleanField):
        return _boolean_icon(value)
    elif value is None:
        return empty_value_display
    elif isinstance(field, models.DateTimeField):
        return formats.localize(timezone.template_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, (models.IntegerField, models.FloatField)):
        return formats.number_format(value)
    elif isinstance(field, models.FileField) and value:
        return format_html('<a href=""{}"">{}</a>', value.url, value)
    elif isinstance(field, models.JSONField) and value:
        try:
            return json.dumps(value, ensure_ascii=False, cls=field.encoder)
        except TypeError:
            return display_for_value(value, empty_value_display)
    else:
        return display_for_value(value, empty_value_display)
}}}

I think this line:
{{{
elif isinstance(field, models.JSONField) and value:
}}}

should be like this:
{{{
elif isinstance(field, models.JSONField):
}}}

because of empty list could be dumps and shouldn't be joined.
Join for empty list return empty string, and this looks confusion.

Before (Now)
{{{
NAME     VALUE
TEST              
}}}

After
{{{
NAME     VALUE
TEST     []
}}}
"	Cleanup/optimization	closed	contrib.admin	5.0	Normal	wontfix			Unreviewed	0	0	0	0	1	0