:date: 2020-04-25

========================
Saturday, April 25, 2020
========================

.. 25.04.2019 02.50-04.45
.. 25.04.2019 11:25-12:15 partner details + misc
.. 25.04.2019 12:15-12:35 move municipality field from avanti to courntries
.. 26.04.2019 03:55-05:23 support remote field pointing to virtual FK
.. 26.04.2019 17:45-18:11 use get_queryset()
.. 26.04.2019 19:05-19:45 municipality_choices
.. 26.04.2019 22:53-23:16 municipality_choices (Lino doesn't find chooser for remote fields)
.. 27.04.2019 04:30-05:52 municipality_choices (Lino doesn't find chooser for remote fields)
.. 27.04.2019 10:03-10:26 verbose_name for municipality
.. 27.04.2019 10:58- review book tests


This weekend I moved the virtual :attr:`municipality
<lino_xl.lib.countries.CountryCity.municipality>` field from :ref:`avanti` to
:mod:`lino_xl.lib.countries` because we will also use it for :ref:`presto`.
Also this field is now a virtual ForeignKey field (and no longer a
:func:`lino.core.fields.displayfield`).

I did this because I want :ref:`presto` to be able to filter calendar entries by
the municipality.  That is, I wanted, in :class:`cal.AllEntries`, a table
parameter "Municipality" that, if set, would show only calendar entries whose
:attr:`lino_xl.lib.cal.Entry.project` field points to a
:class:`lino_presto.lib.presto.Client` who lives either in that :term:`place` or
in a place that is part of it.

This change caused a series of internal optimizations.

After doing it, I realized that it was not really necessary for :ref:`presto`
because I they simply print "service reports" using the
:xfile:`service_report.weasy.html
<sales/VatProductInvoice/service_report.weasy.html>` template.

New developer feature : Lino now also understands remote fields that forward to
a virtualfield as actor parameters.  The application developer must define
themselves how to translate this parameter into a queryset filter by providing a
custom :meth:`get_request_queryset` method.

The virtual municipality field and its chooser is defined on the
:class:`lino_xl.lib.countries.CountryCity` mixin. Presto uses it in
:mod:`lino_presto.lib.cal`.

.. AttributeError: 'VirtualField' object has no attribute 'get_lookup'

.. Exception: lino.core.layouts.ParamsLayout on lino_xl.lib.cal.ui.AllEntries
  has no data element 'project__municipality ('VirtualField' object has no attribute 'blank')'

I moved some internal utility functions from one module to another
(make_converter, make_remote_field, get_chooser_for_field etc).
The caching in check_for_chooser() didn't actually work.

.. dt docs/blog/2020/0425.rst

>>> from lino import startup
>>> startup('lino_presto.projects.presto1.settings.doctests')
>>> from lino.api.doctest import *
>>> ses = rt.login('robin')

Note that Lino's :class:`lino.core.fields.RemoteField` has nothing to do with
Django's :attr:`remote_field` of a FK field.

>>> fld = rt.models.contacts.Partner._meta.get_field('city')
>>> fld.remote_field
<ManyToOneRel: contacts.partner>