Using a ArrayField on Meta.unique_together throws "unhashable type: 'list'" on validate_unique method

[Gleber Diniz]

It happens on a second save (when there is already data to be validated)

On this line: "if row_data in seen_data:", because row_data contains a list and seen_data is a set (row_data: (1, [1, 1]) / seen_data: set())

Example to reproduce:

models:

class Map(models.Model):
    name = models.CharField(_('name'), max_length=128)


class MapSpot(models.Model):
    map = models.ForeignKey('body.Map', related_name='spots')
    position = ArrayField(models.IntegerField(), size=2)

    class Meta:
        unique_together = [('map', 'position')]

admin:

class MapSpotInline(admin.TabularInline):
    model = MapSpot
    extra = 0


@admin.register(Map)
class MapAdmin(admin.ModelAdmin):
    inlines = [MapSpotInline]