Opened 17 years ago

Closed 17 years ago

#6369 closed (duplicate)

ModelForm fields ordering when Meta.fields is set

Reported by: Luke Garner <dj-t@…> Owned by: nobody
Component: Forms Version: dev
Severity: Keywords:
Cc: Triage Stage: Accepted
Has patch: yes Needs documentation: yes
Needs tests: yes Patch needs improvement: yes
Easy pickings: no UI/UX: no

Description (last modified by Gary Wilson)

Field ordering is currently determined by the order the fields were originally defined in the model. However, if the user specifically defines the fields to use in Meta.fields, it's safe to assume that's the order the user wants the fields to be outputted in.

Right now, this is accomplished with:

class myForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(myForm, self).__init__(*args, **kwargs)
        self.fields.keyOrder = self.Meta.fields #This line should be unnecessary
    class Meta:
        model = myModel
        fields = ['field_3', 'field_2', 'field_9']

The new version would just be:

class myForm(forms.ModelForm):
    class Meta:
        model = myModel
        fields = ['field_3', 'field_2', 'field_9']

Attachments (4)

modelfield_order.diff (584 bytes ) - added by Luke Garner <dj-t@…> 17 years ago.
modelfield_order_2.diff (555 bytes ) - added by Luke Garner <dj-t@…> 17 years ago.
modelfield_order_3.diff (875 bytes ) - added by Luke Garner <dj-t@…> 17 years ago.
ModelField fields ordering (now with error handling)
modelfield_order_3.2.diff (876 bytes ) - added by Luke Garner <dj-t@…> 17 years ago.
ModelField fields ordering (now with error handling)

Download all attachments as: .zip

Change History (9)

by Luke Garner <dj-t@…>, 17 years ago

Attachment: modelfield_order.diff added

comment:1 by Gary Wilson, 17 years ago

Description: modified (diff)
Needs documentation: set
Needs tests: set
Patch needs improvement: set
Triage Stage: UnreviewedAccepted

Sounds like the right thing to do. It's even a TODO in the code comments :)

As far as the patch goes, assigning directly to keyOrder is not a good idea. IMO, keyOrder looks like it should be a private attribute. Anyway, by blindly assigning to keyOrder without checking to see if those keys exist in the SortedDict would cause bad things to happen.

comment:2 by Gary Wilson, 17 years ago

We should put the fields in the correct order in the newforms/models.py code.

by Luke Garner <dj-t@…>, 17 years ago

Attachment: modelfield_order_2.diff added

comment:3 by Luke Garner <dj-t@…>, 17 years ago

As far as I'm aware, there's no way to change the order of a SortedDict other than directly editing keyOrder. I've added a new patch which checks to ensure the fields are in keyOrder before reassigning them. I'm not sure this is 100% necessary, though. If Meta.fields contains a field that isn't in the attrsbase_fields SortedDict, then the program is going to fail anyway.

Do you think the best approach is to put in a descriptive error message to raise, if Model.fields is incorrect?

by Luke Garner <dj-t@…>, 17 years ago

Attachment: modelfield_order_3.diff added

ModelField fields ordering (now with error handling)

by Luke Garner <dj-t@…>, 17 years ago

Attachment: modelfield_order_3.2.diff added

ModelField fields ordering (now with error handling)

comment:4 by anonymous, 17 years ago

How about performing a set.difference between opts.fields and keyOrder? This way, the error message could return all of the erroneous fields instead of just the first one.

comment:5 by James Bennett, 17 years ago

Resolution: duplicate
Status: newclosed

Duplicate of #5986, which has several proposals and recent activity.

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