INTPYTHON-483 Add EmbeddedModelArrayField

[timgraham]

Querying support will be added later (#303).

fixes #219

[WaVEV]

LGTM, only few details to clarify.

support for nested fields added

[aclark4life]

@timgraham If Company embeds Project and Project embeds Invoice and embeds Time, can I set extra_forms on any of the nested models below Project ?

class CompanyAdminForm(forms.ModelForm):                                        
    class Meta:                                                                 
        model = Company                                                         
        fields = "__all__"                                                      
        widgets = {                                                             
            "website": forms.URLInput(attrs={"size": 60}),                      
        }                                                                       
    projects = EmbeddedModelArrayField(Project,                                                                                                             
        prefix="project", extra_forms=0,                                        
    )                                             

Models

from django.db import models
from django_mongodb_backend.fields import EmbeddedModelArrayField
from django_mongodb_backend.models import EmbeddedModel


class Company(models.Model):
    name = models.CharField(max_length=255)
    address = models.TextField()
    website = models.URLField()
    projects = EmbeddedModelArrayField("Project")

    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = "Companies"


class Time(EmbeddedModel):
    date = models.DateField(null=True, blank=True)
    hours = models.DecimalField(max_digits=5, decimal_places=2)
    description = models.TextField(blank=True)

    def __str__(self):
        return f"{self.hours}h on {self.date}"


class Invoice(EmbeddedModel):
    number = models.CharField(max_length=50)
    date = models.DateField(null=True, blank=True)
    amount = models.DecimalField(max_digits=10, decimal_places=2)
    times = EmbeddedModelArrayField("Time")  # embedded time entries

    def __str__(self):
        return f"Invoice {self.number}"


class Project(EmbeddedModel):
    name = models.CharField(max_length=255)
    description = models.TextField(blank=True)
    start_date = models.DateField(null=True, blank=True)
    end_date = models.DateField(null=True, blank=True)
    invoices = EmbeddedModelArrayField("Invoice")  # embedded invoices

    def __str__(self):
        return self.name

[timgraham]

I don't think so. The implementation of embedded forms is very limited,
p.s. Please don't set a precedent of using pull request comments as a support channel.

[aclark4life]

I don't think so. The implementation of embedded forms is very limited,

How do I start thinking about supporting this, assuming it's possible and practical to do so ?

p.s. Please don't set a precedent of using pull request comments as a support channel.

I wasn't tracking this feature when the PR got merged, so let's consider this a follow up code review rather than a support request. Based on your response, and previous discussions about polishing the forms, I'm slightly more interested in doing that work now since it appears to be a common use case for nested embeds.

[timgraham]

I don't know, offhand. The implementation is a kludge because Django forms and formsets were never meant to be nested. It may be necessary to rethink the implementation entirely and introduce some new APIs that are better designed for the requirements.