django InlineFormsets errors reporting with formset error list being empty

Question

I have a strange error on creation using Django inline formsets.

Django is reporting formset errors, so it doesn't finish the creation.

Also I tested is_valid and it returns true. What is wrong ?

but if I check them there is nothing in the dictionary of errors:

1.

 {{formset.errors}}
[{}, {}, {}, {}, {}]

2.

{%  if formset.errors %}
        {% for error  in formset.errors %}
            error {{ error }}
        {% endfor %}
{%  endif %} 

{}

I think I understand the issue:

{%  if formset.errors %} even if I have [{}, {}, {}, {}, {}] will pass.

If I use {% if not formset.errors %}, will block also when I have real errors.

Checking if a list is empty is not working, because is not really empty, it has empty dictionaries.

I can use a loop inside the form list to check the dictionaries, but going this for each field or form/formset I don't see it as a good option.

Alasdair · Accepted Answer · 2018-03-06 10:26:39Z

4

Firstly, check that the formset is bound.

formset.is_bound

If you haven't bound the formset to any data, then it won't have any errors but it will never be valid.

Secondly, make sure you are calling the is_valid method

formset.is_valid()

Finally, note that formset.errors returns a list of dictionaries containing the errors for each form. There is also formset.non_form_errors(), whic returns errors that do not belong to a particular form.

answered Mar 6, 2018 at 10:26

Alasdair

310k59 gold badges605 silver badges534 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

user3541631 Over a year ago

is_valid is called and returns true, but it is in form. I'm doing this check in the templates to show the errors. How can I check is bound in the template ?

Alasdair Over a year ago

If you are definitely calling is_valid() then the form is bound - you use formset.is_valid in your question so that wasn't clear. It would help if you included some more information (e.g. formset class, view, full template) that reproduces the problem.

Lee Jun Wei Over a year ago

Thanks for this! I was stuck for hours trying to figure out why my formset was not valid when formset.errors returned an empty list. Turns out the cause lies in formset.non_form_errors()

Aikanáro · Accepted Answer · 2024-12-13 15:37:19Z

0

To avoid that you need to follow the "Post Redirect Get" pattern for form submissions. It seems that django expects that you follow that pattern. If you do, the formset.errors will have real errors if they are instead of just empty dict objects.

When the you submit the form with POST call formset.is_valid, if is valid you do the redirect to a GET view, if not you return the template and read the errors.

answered Dec 13, 2024 at 15:37

Aikanáro

8593 gold badges20 silver badges44 bronze badges

Collectives™ on Stack Overflow

django InlineFormsets errors reporting with formset error list being empty

2 Answers 2

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related