Make the "must be unique" error messages in ModelForms customizable

[Alexander_Nesterov]

feature request (?)
model:

class Context(models.Model): 
    name        = models.CharField(unique=True)

form:

class ContextForm(forms.ModelForm): 
    name = forms.CharField() 
    class Meta: 
        model = Context

example:

form = ContextForm(request.POST)  
if form.is_valid(): 
    form.save()

Is there any way to override an error message of validate_unique: u"%(model_name)s with this %(field_label)s already exists."?

class ContextForm(forms.ModelForm): 
    name = forms.CharField(error_messages={'unique': u'My custom message'}) 

[Oroku Saki]

See ​this thread before applying a patch. I'll work on a patch after 1.2 release is complete.

orokusaki

[Anand Kumria]

Is this something appropriate for Django 1.4 now?

[Julien Phalip]

Replying to wildfire:

Is this something appropriate for Django 1.4 now?

Not until there is a patch with tests and doc ;)

[Leah Culver]

I've added a rough patch for this. To specify a custom error message for the unique contraint, you'll need to do something like this:

class Context(models.Model): 
    name = models.CharField(error_messages={'unique': u'My custom message'}) 

I don't know a lot about ModelForms vs. Forms but I can't seem to get this to work for plain Forms. Should this also be a Form error_message key?

I'm also not sure where to put the docs since the Model error_messages parameter is documented but lacking specificity (​https://docs.djangoproject.com/en/1.3/ref/models/fields/#error-messages). Should I make this more specific?

[anonymous]

You've got a bare except on #168, with a ambiguous failure message. I'd just remove that altogether.

[Leah Culver]

Added documentation.

[Leah Culver]

I've created a new ticket (#16192) for unique_together custom error messages since this is more difficult.

[Leah Culver]

Updated my email address in AUTHORS

[Andrew Godwin]

In [16345]:

Fixed #8913 - Make "must be unique" error messages customisable. Thanks to Leah Culver.

[Uznick <uznick@…>]

The error message is still not customizable when it's set in the ModelForm.

Example:

class InformationSubscriber(models.Model):
    email = models.EmailField(u"E-mail", unique=True)

class InformationSubscribeForm(forms.ModelForm):
    email = forms.EmailField(label=u"E-mail", error_messages={'unique': u"You are already subscribed to our news",})

When the form is submitted, the error is: Information Subscriber with this E-mail already exists.

And when I set the error_messages in the Model, like

class InformationSubscriber(models.Model):
    email = models.EmailField(u"E-mail", unique=True, error_messages={'unique': u"You are already subscribed to our news",})

class InformationSubscribeForm(forms.ModelForm):
    email = forms.EmailField(label=u"E-mail")

The error message is correct: You are already subscribed to our news.

But the problem is, that there should be an option to set a unique error message on the form-level, not on the level of the whole model itself.

[Claude Paroz]

I would suggest to open a new ticket, as allowing the message to be set on the form level is a different story. Currently, validate_unique may produce several errors to pass to ValidationError, so we cannot simply set code and params to be able to catch it at the form level.