Deleting "extra" inlines in admin should not be possible.

[Guan]

​writing-your-first-django-app-part-7

There is a description: Note that you can’t remove the original three slots.

But I find that the original three slots is able to be removed in Django 3.1.5. The code is as follows:

# polls.models.py

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField(verbose_name="date published")

    def __str__(self):
        return self.question_text

    def was_published_recently(self):
        now = timezone.now()
        return now >= self.pub_date >= now - datetime.timedelta(days=1)


class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

    def __str__(self):
        return self.choice_text

# polls.admin.py

class ChoiceInline(admin.StackedInline):
    model = Choice
    extra = 3


class QuestionAdmin(admin.ModelAdmin):
    # fields = ["pub_date", "question_text"]
    fieldsets = [
        (None, {"fields": ["question_text"]}),
        ("Date Information", {"fields": ["pub_date"]})
    ]
    inlines = [ChoiceInline]


admin.site.register(Question, QuestionAdmin)

The image is:

[Mariusz Felisiak]

Thanks for this report. This is not an issue in docs by a regression in 24e540fbd71bd2b0843e751bde61ad0052a811b3 (see #29087). Deleting inlines added with extra should not be possible.

[Hasan Ramezani]

I just created an ​initial draft patch which is not working. I will complete it soon.

[Hasan Ramezani]

Now it is ready for review. I am not sure about the logic in toggleDeleteButtonVisibility function

[Guan]

Replying to Hasan Ramezani:

Now it is ready for review. I am not sure about the logic in toggleDeleteButtonVisibility function

Hi! Thanks for your work. But there are probably two slight flaws I think:

1. When ValidationError is raised, it's no 'X' at the top right of form. That the UX is not comfortable is ticket #29087 talked about.
2. For toggleDeleteButtonVisibility function, my opinion comes from ​**extra** form could not be removed and ​if a formset contains no data, then extra + min_num empty forms will be displayed. So the calculation I think is：

   const isFormOverload = function() {                                                                                                                                                                                        
       const totalFormNum = ~~totalForms.val();                                                                                                                                                                               
       const initialFormNum = ~~initialForms.val();                                                                                                                                                                           
       const minFormNum = ~~minForms.val();                                                                                                                                                                                   
       const extraFormNum = ~~extraForms.val();                                                                                                                                                                               
   
       const emptyFormNum = totalFormNum - initialFormNum;                                                                                                                                                                    
       if (initialFormNum >= emptyFormNum) {                                                                                                                                                                                  
           return emptyFormNum > extraFormNum;                                                                                                                                                                                
       }                                                                                                                                                                                                                      
       return emptyFormNum > extraFormNum + minFormNum - initialFormNum;                                                                                                                                                      
   } 
   

When isFormOverload returns true, all forms show 'X'.

I created patch ​PR and I'd like to know your opinion.

[Hasan Ramezani]

Thanks Guan for the new calculation. I added your patch to my PR as separate commiet

[Carlton Gibson]

Reviewing, I think we just missed a doc change with 24e540fbd71bd2b0843e751bde61ad0052a811b3. I've suggest a ​new PR making that change.

[Carlton Gibson]

Having conferred with Mariusz, we will go with the documentation change. Thanks all.

[Carlton Gibson <carlton@…>]

In f4272d00:

Fixed #32348, Refs #29087 -- Corrected tutorial for updated deleting inlines UI.

Updated tutorial to match change in 24e540fbd71bd2b0843e751bde61ad0052a811b3
allowing deletion of original extra inlines.

[Carlton Gibson <carlton.gibson@…>]

In 4dbbe37:

[3.2.x] Fixed #32348, Refs #29087 -- Corrected tutorial for updated deleting inlines UI.

Updated tutorial to match change in 24e540fbd71bd2b0843e751bde61ad0052a811b3
allowing deletion of original extra inlines.

Backport of f4272d000af598018247fe9687dac0fd02a29a7c from master

[Carlton Gibson <carlton.gibson@…>]

In fa203f17:

[3.1.x] Fixed #32348, Refs #29087 -- Corrected tutorial for updated deleting inlines UI.

Updated tutorial to match change in 24e540fbd71bd2b0843e751bde61ad0052a811b3
allowing deletion of original extra inlines.

Backport of f4272d000af598018247fe9687dac0fd02a29a7c from master