Re: IndexError when validating model formsets

Nevermind.
I found that I was not instantiating the formset with the "instance"
argument, naming the parent object. Once that was added, everything
worked as designed.

-AB

On Thu, Dec 23, 2010 at 9:02 PM, Andrew Badstubner
<andrew@badstubner.com> wrote:
> I have a form that contains a parent object in the header and then
> lists the children as a formset in the same HTML <form>. I can create
> new "families" of parent objects and children just fine, but I can't
> edit them. I've tracked the error down to the line where the view is
> trying to instantiate the FormSet object for the children from the
> POST arguments. Python is complaining about an IndexError (see
> traceback below).
>
> I've found that I can modify parents just fine when there are zero
> children, but as soon as there are child objects, everything falls
> apart when the model formset is being instantiated.
>
> Has anyone seen this before?
>
> Many thanks for any help,
>
> Andy
>
>
> =================================
>
> Environment:
>
> Request Method: POST
> Request URL: http://127.0.0.1:8000/mixture/13/edit/
> Django Version: 1.2.1
> Python Version: 2.6.1
> Installed Applications:
> ['django.contrib.auth',
>  'django.contrib.contenttypes',
>  'django.contrib.sessions',
>  'django.contrib.sites',
>  'django.contrib.messages',
>  'django.contrib.admin',
>  'django.contrib.admindocs',
>  'form_utils',
>  'sgm.general',
>  'sgm.mixture',
>  'sgm.msds',
>  'sgm.account',
>  'sgm.errors']
> Installed Middleware:
> ('django.middleware.common.CommonMiddleware',
>  'django.contrib.sessions.middleware.SessionMiddleware',
>  'django.middleware.csrf.CsrfViewMiddleware',
>  'django.contrib.auth.middleware.AuthenticationMiddleware',
>  'django.contrib.messages.middleware.MessageMiddleware',
>  'debug_toolbar.middleware.DebugToolbarMiddleware')
>
>
> Traceback:
> File "/Library/Python/2.6/site-packages/django/core/handlers/base.py"
> in get_response
>  100.                     response = callback(request,
> *callback_args, **callback_kwargs)
> File "/Library/Python/2.6/site-packages/django/contrib/auth/decorators.py"
> in _wrapped_view
>  25.                 return view_func(request, *args, **kwargs)
> File "/Users/abadstubner/Documents/Projects/specialty_gas_manager/../specialty_gas_manager/mixture/views.py"
> in edit_mixture
>  78.         comp_formset = forms.CustomerMixtureComponentFormset(
> request.POST, prefix='comps' )
> File "/Library/Python/2.6/site-packages/django/forms/models.py" in __init__
>  698.                                                 queryset=qs)
> File "/Library/Python/2.6/site-packages/django/forms/models.py" in __init__
>  423.         super(BaseModelFormSet, self).__init__(**defaults)
> File "/Library/Python/2.6/site-packages/django/forms/formsets.py" in __init__
>  47.         self._construct_forms()
> File "/Library/Python/2.6/site-packages/django/forms/formsets.py" in
> _construct_forms
>  97.             self.forms.append(self._construct_form(i))
> File "/Library/Python/2.6/site-packages/django/forms/models.py" in
> _construct_form
>  711.         form = super(BaseInlineFormSet,
> self)._construct_form(i, **kwargs)
> File "/Library/Python/2.6/site-packages/django/forms/models.py" in
> _construct_form
>  447.             kwargs['instance'] = self.get_queryset()[i]
> File "/Library/Python/2.6/site-packages/django/db/models/query.py" in
> __getitem__
>  172.             return self._result_cache[k]
>
> Exception Type: IndexError at /mixture/13/edit/
> Exception Value: list index out of range
>
> Here's the POST data, in case anyone can see anything obvious there:
> account u'1'
> comments        u''
> comps-0-concentration   u'20%'
> comps-0-customermixture u'13'
> comps-0-gas     u'Benzene'
> comps-0-id      u'16'
> comps-0-solubility      u''
> comps-1-concentration   u'20%'
> comps-1-customermixture u'13'
> comps-1-gas     u'Acetaldehyde'
> comps-1-id      u'17'
> comps-1-solubility      u''
> comps-2-concentration   u'Balance'
> comps-2-customermixture u'13'
> comps-2-gas     u'Carbon Dioxide'
> comps-2-id      u'18'
> comps-2-solubility      u''
> comps-INITIAL_FORMS     u'3'
> comps-MAX_NUM_FORMS     u''
> comps-TOTAL_FORMS       u'3'
> csrfmiddlewaretoken     u'3...a' #redacted
> engineering_controls    u'1'
> hazard_warning  u'2'
> name    u'Sample Mixture3'
>

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