[Django] #19427: Lacking Documentation on Custom Related Fields Pre-Save Override
Django
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Reporter: s.shanabrook@… | Owner: nobody
Type: Bug | Status: new
Component: Documentation | Version: 1.4
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 1 | UI/UX: 0
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The process to create a custom field that inherits a `OneToOneField` or a
`ForeignKey ` (and I assume a `ManyToManyField` as well) and overrides the
`pre_save` method, is not clear in the documentation.
[https://docs.djangoproject.com/en/dev/howto/custom-model-fields
/#preprocessing-values-before-saving The section] that outlines how to
override the `pre_save` method says that the attribute name is
`self.attname`, when in fact on a related field, `self.attname` is the
model's id field for the related object.
So in order to actually modify the related object and then save it, you
must do something like this:
{{{
#!python
class CustomRelatedField(ForeignKey):
def pre_save(self, model_instance, add):
related_object = getattr(model_instance, self.name)
# Do stuff with object, custom saving
id = getattr(related_object, 'id', None)
setattr(model_instance, self.attname, id)
setattr(model_instance, self.name, redirect)
return id
}}}
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Ticket URL: <https://code.djangoproject.com/ticket/19427>
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Django
Reporter: s.shanabrook@… | Owner: nobody
Type: Bug | Status: new
Component: Documentation | Version: 1.4
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 1
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
Changes (by s.shanabrook@…):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 1
--
Ticket URL: <https://code.djangoproject.com/ticket/19427#comment:1>
Django
Reporter: s.shanabrook@… | Owner: nobody
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.4
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 1
Easy pickings: 1 | UI/UX: 0
Changes (by russellm):
* type: Bug => Cleanup/optimization
* stage: Unreviewed => Accepted
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Ticket URL: <https://code.djangoproject.com/ticket/19427#comment:2>
Django
Reporter: s.shanabrook@… | Owner:
Type: | vijay_shanker
Cleanup/optimization | Status: assigned
Component: Documentation | Version: 1.4
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 1
Easy pickings: 1 | UI/UX: 0
Changes (by vijay_shanker):
* owner: nobody => vijay_shanker
* status: new => assigned
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Ticket URL: <https://code.djangoproject.com/ticket/19427#comment:3>
Django
Reporter: s.shanabrook@… | Owner: anonymous
Type: | Status: assigned
Cleanup/optimization | Version: 1.4
Component: Documentation | Resolution:
Severity: Normal | Triage Stage: Accepted
Keywords: | Needs documentation: 1
Has patch: 0 | Patch needs improvement: 0
Needs tests: 0 | UI/UX: 0
Easy pickings: 1 |
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Changes (by anonymous):
* owner: vijay_shanker => anonymous
--
Ticket URL: <https://code.djangoproject.com/ticket/19427#comment:4>
Django
Reporter: s.shanabrook@… | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.4
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 1
Easy pickings: 1 | UI/UX: 0
Changes (by timo):
* owner: anonymous =>
* status: assigned => new
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Ticket URL: <https://code.djangoproject.com/ticket/19427#comment:5>
Django
Reporter: s.shanabrook@… | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.4
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
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Changes (by timo):
* needs_docs: 1 => 0
* easy: 1 => 0
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Ticket URL: <https://code.djangoproject.com/ticket/19427#comment:6>
Django
Reporter: s.shanabrook@… | Owner:
Type: Cleanup/optimization | Status: closed
Component: Documentation | Version: 1.4
Severity: Normal | Resolution: wontfix
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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* status: new => closed
* resolution: => wontfix
Comment:
Not sure what to do here as `attname` isn't referenced in the linked doc
(maybe it's since been removed). This seems in the realm of private API
anyway.
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Ticket URL: <https://code.djangoproject.com/ticket/19427#comment:7>