can not save pages any more in wagtail

Question

when clicking publish or save draft I got this error wagtail.core.models.Page.DoesNotExist: Page matching query does not exist. this happens only with old pages, the newly created pages are being able to be created and saved without any errors

NB: the new pages do not have children pages yet trying to find out what is causing this error despite I did not override the save method any suggestion or hint will be very helpful thank you

here the traceback:

wagtail.core.models.DoesNotExist
wagtail.core.models.Page.DoesNotExist: Page matching query does not exist.

Traceback (most recent call last)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/contrib/staticfiles/handlers.py", line 76, in __call__
return self.application(environ, start_response)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/core/handlers/wsgi.py", line 133, in __call__
response = self.get_response(request)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/core/handlers/base.py", line 130, in get_response
response = self._middleware_chain(request)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/core/handlers/exception.py", line 49, in inner
response = response_for_exception(request, exc)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/core/handlers/exception.py", line 103, in response_for_exception
response = handle_uncaught_exception(request, get_resolver(get_urlconf()), sys.exc_info())
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/core/handlers/exception.py", line 138, in handle_uncaught_exception
return debug.technical_500_response(request, *exc_info)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django_extensions/management/technical_response.py", line 37, in null_technical_500_response
six.reraise(exc_type, exc_value, tb)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/six.py", line 702, in reraise
raise value.with_traceback(tb)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/core/handlers/exception.py", line 47, in inner
response = get_response(request)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/core/handlers/base.py", line 181, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
response = view_func(request, *args, **kwargs)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/wagtail/admin/urls/__init__.py", line 127, in wrapper
return view_func(request, *args, **kwargs)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/wagtail/admin/auth.py", line 172, in decorated_view
response = view_func(request, *args, **kwargs)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/views/generic/base.py", line 70, in view
return self.dispatch(request, *args, **kwargs)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/wagtail/admin/views/pages/edit.py", line 131, in dispatch
return super().dispatch(request)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/views/generic/base.py", line 98, in dispatch
return handler(request, *args, **kwargs)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/wagtail/admin/views/pages/edit.py", line 218, in post
return self.form_valid(self.form)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/wagtail/admin/views/pages/edit.py", line 238, in form_valid
return self.publish_action()
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/wagtail/admin/views/pages/edit.py", line 286, in publish_action
revision.publish(
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/wagtail/core/models.py", line 2972, in publish
page.save()
File "/home/oladhari/gounite-v2/GOunite/v2/home/models.py", line 98, in save
super().save(*args, **kwargs)
File "/usr/lib/python3.8/contextlib.py", line 75, in inner
return func(*args, **kwds)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/wagtail/core/models.py", line 1028, in save
result = super().save(**kwargs)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/modelcluster/models.py", line 199, in save
getattr(self, relation).commit()
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/modelcluster/fields.py", line 202, in commit
item.delete()
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/wagtail/core/models.py", line 1094, in delete
return Page.objects.get(id=self.id).delete(*args, **kwargs)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/db/models/manager.py", line 85, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/oladhari/.virtualenvs/gounite/lib/python3.8/site-packages/django/db/models/query.py", line 429, in get
raise self.model.DoesNotExist(
wagtail.core.models.Page.DoesNotExist: Page matching query does not exist.

Answer 1

The part that is throwing errors looks like code in your models that relates one page to other pages. See this line: return Page.objects.get(id=self.id).delete(*args, **kwargs) ? So I think we need to know what "items" are and how the page you are saving uses them.

Please post the models for the page you are saving and the pages that are referenced as 'items'

Answer 2

Finally resolved it we should not use ParentalKey with a Page model (we were using it in GOPart model which is a Page model, changing it to ForeignKey resolved the error and now we can save the HomePage

class MyModel(RoutablePageMixin, Page, Orderable):

    parent_page_types: list = []

    company = ParentalKey(
        "home.HomePage",
        on_delete=models.SET_NULL,
        verbose_name=_("Company"),
        null=True,
        blank=False,
    )

changing it to:

class MyModel(RoutablePageMixin, Page):

    parent_page_types: list = []

    company = models.ForeignKey(
        "home.HomePage",
        on_delete=models.SET_NULL,
        verbose_name=_("Company"),
        null=True,
        blank=False,
    )

a Page can not be Orderable