=============
Release Notes
=============

v4.2
----

* When exporting via :ref:`admin action<export_via_admin_action>`, the queryset is now filtered on
  :meth:`~import_export.admin.ExportMixin.get_queryset` instead of the Model's default queryset.
  This should have no impact on existing implementations.

  This change also made :meth:`~import_export.admin.ExportMixin.get_valid_export_item_pks` obsolete, as the
  ModelAdmin's :meth:`~import_export.admin.ExportMixin.get_export_queryset`, or
  ModelAdmin's get_queryset can be used instead.
  The :meth:`~import_export.admin.ExportMixin.get_valid_export_item_pks` method is now deprecated.

  See `PR 1890 <https://github.com/django-import-export/django-import-export/issues/1890>`_.

* Removed internal method ``_get_enabled_export_fields()`` in favour of passing the selected fields list as a
  new parameter to :meth:`~import_export.resources.Resource.export_resource` and
  :meth:`~import_export.resources.Resource.get_export_headers`.

* Hide the "Resource" form when it only has one option, to avoid potentially confusing text in the interface like
  "Resource: BookResource". To undo this change, use a form subclass that changes the field’s widget to a
  ``django.forms.Select``.  See `1908 <https://github.com/django-import-export/django-import-export/issues/1908>`_

*  `tablib <https://github.com/jazzband/tablib>`_ has been upgraded from v3.5.0 to 3.6.1.
   This upgrade removes tablib's dependency on `MarkupPy <https://github.com/jazzband/tablib/pull/554>`_ in favour
   of ``ElementTree``.  If you export to HTML, then this change may affect your output format, particularly if you have
   already escaped HTML characters in the text.

   See `issue 1627 <https://github.com/django-import-export/django-import-export/issues/1627>`_.

Breaking changes
^^^^^^^^^^^^^^^^

* This release fixes a regression introduced in v4. From v4.2, numeric, boolean and date/time widgets are written as
  native values to spreadsheet formats (ODS, XLS, XLSX).  This was the default behavior in v3.
  See :ref:`documentation<modify_render_return_type>`.

  This means that the ``coerce_to_string`` value which is passed to :class:`~import_export.widgets.Widget` is now
  ignored if you are exporting to a spreadsheet format from the Admin interface.

  If you have subclassed ``Widget``, ``Field`` or ``Resource``, then you may need to adjust your code to include
  the ``**kwargs`` param as follows:

.. list-table::
   :header-rows: 1

   * - Previous
     - New

   * - ``Widget.render(self, value, obj=None)``
     - ``Widget.render(self, value, obj=None, **kwargs)``

   * - ``Field.export(self, instance)``
     - ``Field.export(self, instance, **kwargs)``

   * - ``Resource.export_field(self, field, instance)``
     - ``Resource.export_field(self, field, instance, **kwargs)``

   * - ``Resource.export_resource(self, instance, selected_fields=None)``
     - ``Resource.export_resource(self, instance, selected_fields=None, **kwargs)``

v4.1
----

The ``Resource.get_fields()`` method is no longer called within the package and has been deprecated.
If you have overridden this method then it should be removed.

v4.0
----

v4 introduces significant updates to import-export.  We have taken the opportunity to introduce
breaking changes in order to fix some long-standing issues.

Refer to the :doc:`changelog<changelog>` for more information. Please ensure you test
thoroughly before deploying v4 to production.

This guide describes the major changes and how to upgrade.

Installation
^^^^^^^^^^^^

We have modified installation methods to allow for optional dependencies.
This means that you have to explicitly declare dependencies when installing import-export.

If you are not sure, or want to preserve the pre-v4 behaviour, then ensure that
import-export is installed as follows (either in your requirements file or during
installation)::

  django-import-export[all]

Functional changes
^^^^^^^^^^^^^^^^^^

CharWidget
""""""""""

Constructor arguments are dynamically set during instantiation based on the properties of the underlying Django
db CharField.  If the db field has `blank <https://docs.djangoproject.com/en/stable/ref/models/fields/#blank>`_
set to True, then incoming values of empty strings or null are stored as empty strings.
See :class:`~import_export.widgets.CharWidget`.

:meth:`~import_export.widgets.CharWidget.clean` will now return a string type as the default.
The ``coerce_to_string`` option introduced in v3 is no longer used in this method.

Validation error messages
"""""""""""""""""""""""""

The following widgets have had validation error messages updated:

* :class:`~import_export.widgets.DateWidget`
* :class:`~import_export.widgets.TimeWidget`
* :class:`~import_export.widgets.DateTimeWidget`
* :class:`~import_export.widgets.DurationWidget`

Export format
"""""""""""""

We have standardized the export output which is returned from
:meth:`~import_export.widgets.Widget.render`.

Prior to v4, the export format returned from ``render()`` varied between Widget implementations.
In v4, return values are rendered as strings by default (where applicable), with
``None`` values returned as empty strings.  Widget params can modify this behavior.

This causes a change when exporting to Excel.  In v3, certain fields, such as numeric values, were rendered as their
native type.  In v4, all fields are now rendered as strings.  To preserve the v3 behavior when exporting to Excel,
set the ``coerce_to_string`` param to ``False``.  See :ref:`documentation<modify_render_return_type>`.

:doc:`Widget API documentation<api_widgets>`.

Export field order
""""""""""""""""""

The ordering rules for exported fields has been standardized. See :ref:`documentation<field_ordering>`.

Error output
""""""""""""

If the ``raise_errors`` parameter of :meth:`~import_export.resources.Resource.import_data` is ``True``, then an instance
of :class:`~import_export.exceptions.ImportError` is raised.  This exception wraps the underlying exception.

See `this PR <https://github.com/django-import-export/django-import-export/issues/1729>`_.

Check ``import_id_fields``
""""""""""""""""""""""""""

Prior to v4 we had numerous issues where users were confused when imports failed due to declared ``import_id_fields``
not being present in the dataset.  We added functionality in v4 to check for this and to raise a clearer error message.

In some use-cases, it is a requirement that ``import_id_fields`` are not in the dataset, and are generated dynamically.
If this affects your implementation, start with the documentation :ref:`here<import_id_fields_error_on_import>`.

Deprecations
^^^^^^^^^^^^

* The ``obj`` param passed to :meth:`~import_export.widgets.Widget.render` is deprecated.
  The :meth:`~import_export.widgets.Widget.render` method should not need to have a reference to
  model instance.
  The call to :meth:`~import_export.widgets.Widget.render` from :meth:`~import_export.fields.Field.export` has been removed.

* Use of ``ExportViewFormMixin`` is deprecated.  See `this issue <https://github.com/django-import-export/django-import-export/issues/1666>`_.

* See :ref:`renamed_methods`.

* In the Admin UI, the declaration of ``resource_class`` is replaced by ``resource_classes``::

      class BookAdmin(ImportExportModelAdmin):
        # remove this line
        # resource_class = BookResource
        # replace with this
        resource_classes = [BookResource]

Admin UI
^^^^^^^^

LogEntry
""""""""

``LogEntry`` instances are created during import for creates, updates and deletes.
The functionality to store ``LogEntry`` has changed in v4 in order to address a deprecation in Django 5.
For this to work correctly, deleted instances are now always copied and retained in each
:class:`~import_export.results.RowResult` so that they can be recorded in each ``LogEntry``.

This only occurs for delete operations initiated from the Admin UI.

Export action
"""""""""""""

The export action has been updated to include the export workflow.  Prior to v4, it was possible to select export
selected items using an export admin action.  However this meant that the export workflow was skipped and it was not
possible to select the export resource.  This has been fixed in v4 so that export workflow is now present when
exporting via the Admin UI action.  For more information see :ref:`export documentation<export_via_admin_action>`.

Export selected fields
""""""""""""""""""""""

The :ref:`export 'confirm' page<export_confirm>` now includes selectable fields for export.
If you wish to revert to the previous (v3) version of the export confirm screen, add a
:attr:`~import_export.admin.ExportMixin.export_form_class` declaration to your Admin class subclass, for example::

  class BookAdmin(ImportExportModelAdmin):
    export_form_class = ExportForm

Success message
"""""""""""""""

The success message shown on successful import has been updated to include the number of 'deleted' and 'skipped' rows.
See `this PR <https://github.com/django-import-export/django-import-export/issues/1691>`_.

Import error messages
"""""""""""""""""""""

The default error message for import errors has been modified to simplify the format.
Error messages now contain the error message only by default.  The row and traceback are not presented.

The original format can be restored by setting :attr:`~import_export.admin.ImportMixin.import_error_display` on the
Admin class definition.  For example::

  class BookAdmin(ImportExportModelAdmin):
    import_error_display = ("message", "row", "traceback")


See `this issue <https://github.com/django-import-export/django-import-export/issues/1724>`_.

API changes
^^^^^^^^^^^

v4 of import-export contains a number of changes to the API.  These changes are summarized in the table below.
Refer to
`this PR <https://github.com/django-import-export/django-import-export/pull/1641/>`_ for detailed information.

If you have customized import-export by overriding methods, then you may have to modify your installation before
working with v4.

If you have not overridden any methods then you should not be affected by these changes and no changes to your code
should be necessary.

The API changes include changes to method arguments, although some method names have changed.

Methods which process row data have been updated so that method args are standardized.
This has been done to resolve inconsistency issues where the parameters differed between method calls, and to allow
easier extensibility.

:class:`import_export.resources.Resource`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. _renamed_methods:

Renamed methods
"""""""""""""""

.. list-table::
   :header-rows: 1

   * - Previous
     - New
     - Summary

   * - ``import_obj(self, obj, data, dry_run, **kwargs)``
     - ``import_instance(self, instance, row, **kwargs)``
     -  * ``obj`` param renamed to ``instance``
        * ``data`` param renamed to ``row``
        * ``dry_run`` param now in ``kwargs``

   * - ``after_import_instance(self, instance, new, row_number=None, **kwargs)``
     - ``after_init_instance(self, instance, new, row, **kwargs)``
     -  * ``row`` added as mandatory arg
        * ``row_number`` now in ``kwargs``

Parameter changes
"""""""""""""""""

This section describes methods in which the parameters have changed.

.. list-table::
   :header-rows: 1

   * - Previous
     - New
     - Summary

   * - ``before_import(self, dataset, using_transactions, dry_run, **kwargs)``
     - ``before_import(self, dataset, **kwargs)``
     -  * ``using_transactions`` param now in ``kwargs``
        * ``dry_run`` param now in ``kwargs``

   * - ``after_import(self, dataset, result, using_transactions, dry_run, **kwargs)``
     - ``after_import(self, dataset, result, **kwargs)``
     -  * ``using_transactions`` param now in ``kwargs``
        * ``dry_run`` param now in ``kwargs``

   * - ``before_import_row(self, row, row_number=None, **kwargs)``
     - ``before_import_row(self, row, **kwargs)``
     - * ``row_number`` now in ``kwargs``

   * - ``after_import_row(self, row, row_result, row_number=None, **kwargs)``
     - ``after_import_row(self, row, row_result, **kwargs)``
     - * ``row_number`` now in ``kwargs``

   * - ``import_row(self, row, instance_loader, using_transactions=True, dry_run=False, **kwargs)``
     - ``import_row(self, row, instance_loader, **kwargs)``
     - * ``dry_run`` param now in ``kwargs``
       * ``using_transactions`` param now in ``kwargs``

   * - ``save_instance(self, instance, is_create, using_transactions=True, dry_run=False)``
     - ``save_instance(self, instance, is_create, row, **kwargs)``
     - * ``dry_run`` param now in ``kwargs``
       * ``using_transactions`` param now in ``kwargs``
       * ``row`` added as mandatory arg

   * - ``save_m2m(self, obj, data, using_transactions, dry_run)``
     - ``save_m2m(self, instance, row, **kwargs)``
     - * ``row`` added as mandatory arg
       * ``obj`` renamed to ``instance``
       * ``data`` renamed to ``row``
       * ``dry_run`` param now in ``kwargs``
       * ``using_transactions`` param now in ``kwargs``

   * - ``before_save_instance(self, instance, using_transactions, dry_run)``
     - ``before_save_instance(self, instance, row, **kwargs)``
     - * ``row`` added as mandatory arg
       * ``dry_run`` param now in ``kwargs``
       * ``using_transactions`` param now in ``kwargs``

   * - ``after_save_instance(self, instance, using_transactions, dry_run)``
     - ``after_save_instance(self, instance, row, **kwargs)``
     - * ``row`` added as mandatory arg
       * ``dry_run`` param now in ``kwargs``
       * ``using_transactions`` param now in ``kwargs``

   * - ``delete_instance(self, instance, using_transactions=True, dry_run=False)``
     - ``delete_instance(self, instance, row, **kwargs)``
     - * ``row`` added as mandatory arg
       * ``dry_run`` param now in ``kwargs``
       * ``using_transactions`` param now in ``kwargs``

   * - ``before_delete_instance(self, instance, dry_run)``
     - ``before_delete_instance(self, instance, row, **kwargs)``
     - * ``row`` added as mandatory arg
       * ``dry_run`` param now in ``kwargs``
       * ``using_transactions`` param now in ``kwargs``

   * - ``after_delete_instance(self, instance, dry_run)``
     - ``after_delete_instance(self, instance, row, **kwargs)``
     - * ``row`` added as mandatory arg
       * ``dry_run`` param now in ``kwargs``
       * ``using_transactions`` param now in ``kwargs``

   * - ``import_field(self, field, obj, data, is_m2m=False, **kwargs)``
     - ``import_field(self, field, instance, row, is_m2m=False, **kwargs):``
     - * ``obj`` renamed to ``instance``
       * ``data`` renamed to ``row``

   * - ``before_export(self, queryset, *args, **kwargs)``
     - ``before_export(self, queryset, **kwargs)``
     - * unused ``*args`` list removed

   * - ``after_export(self, queryset, data, *args, **kwargs)``
     - ``after_export(self, queryset, dataset, **kwargs)``
     - * unused ``*args`` list removed
       * ``data`` renamed to ``dataset``

   * - ``filter_export(self, queryset, *args, **kwargs)``
     - ``filter_export(self, queryset, **kwargs)``
     - * unused ``*args`` list removed

   * - ``export_field(self, field, obj)``
     - ``export_field(self, field, instance)``
     - * ``obj`` renamed to ``instance``

   * - ``export_resource(self, obj)``
     - ``export_resource(self, instance, fields=None)``
     - * ``obj`` renamed to ``instance``
       * ``fields`` passed as kwarg

   * - ``export(self, *args, queryset=None, **kwargs)``
     - ``export(self, queryset=None, **kwargs)``
     - * unused ``*args`` list removed

   * - ``get_export_headers(self)``
     - ``get_export_headers(self, fields=None)``
     - * ``fields`` passed as kwarg


:class:`import_export.mixins.BaseImportExportMixin`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Parameter changes
"""""""""""""""""

.. list-table::
   :header-rows: 1

   * - Previous
     - New
     - Summary

   * - ``get_resource_classes(self)``
     - ``get_resource_classes(self, request)``
     -  * Added ``request`` param

   * - ``get_resource_kwargs(self, request, *args, **kwargs)``
     - ``get_resource_kwargs(self, request, **kwargs)``
     -  * unused ``*args`` list removed

:class:`import_export.mixins.BaseImportMixin`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Parameter changes
"""""""""""""""""

.. list-table::
   :header-rows: 1

   * - Previous
     - New
     - Summary

   * - ``get_import_resource_kwargs(self, request, *args, **kwargs)``
     - ``get_import_resource_kwargs(self, request, **kwargs)``
     -  * unused ``*args`` list removed

   * - ``get_import_resource_classes(self)``
     - ``get_import_resource_classes(self, request)``
     -  * Added ``request`` param

   * - ``choose_import_resource_class(self, form)``
     - ``choose_import_resource_class(self, form, request)``
     -  * Added ``request`` param

:class:`import_export.mixins.BaseExportMixin`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Parameter changes
"""""""""""""""""

.. list-table::
   :header-rows: 1

   * - Previous
     - New
     - Summary

   * - ``get_export_resource_classes(self)``
     - ``get_export_resource_classes(self, request)``
     -  * Added ``request`` param

   * - ``get_export_resource_kwargs(self, request, *args, **kwargs)``
     - ``get_export_resource_kwargs(self, request, **kwargs)``
     -  * unused ``*args`` list removed

   * - ``get_data_for_export(self, request, queryset, *args, **kwargs)``
     - ``get_data_for_export(self, request, queryset, **kwargs)``
     -  * unused ``*args`` list removed

   * - ``choose_export_resource_class(self, form)``
     - ``choose_export_resource_class(self, form, request)``
     -  * Added ``request`` param


:class:`import_export.fields.Field`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Parameter changes
"""""""""""""""""

.. list-table::
   :header-rows: 1

   * - Previous
     - New
     - Summary

   * - ``clean(self, data, **kwargs)``
     - ``clean(self, row, **kwargs)``
     - * ``data`` renamed to ``row``

   * - ``get_value(self, instance)``
     - ``get_value(self, obj)``
     - * ``obj`` renamed to ``instance``

   * - ``save(self, obj, data, is_m2m=False, **kwargs)``
     - ``save(self, instance, row, is_m2m=False, **kwargs)``
     - * ``obj`` renamed to ``instance``
       * ``data`` renamed to ``row``

   * - ``export(self, obj)``
     - ``export(self, instance)``
     - * ``obj`` renamed to ``instance``


:class:`import_export.forms.ImportExportFormBase`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

If you have subclassed one of the :mod:`~import_export.forms` then you may need to
modify the parameters passed to constructors.

The ``input_format`` field of :class:`~import_export.forms.ImportForm` has been moved to the parent class
(:class:`~import_export.forms.ImportExportFormBase`) and renamed to ``format``.

The ``file_format`` field of :class:`~import_export.forms.ExportForm` has been removed and is now replaced by
:attr:`~import_export.forms.ImportExportFormBase.format`.

Parameter changes
"""""""""""""""""

.. list-table::
   :header-rows: 1

   * - Previous
     - New
     - Summary

   * - ``__init__(self, *args, resources=None, **kwargs)``
     - ``__init__(self, formats, resources, **kwargs)``
     - * ``formats`` added as a mandatory arg
       * ``resources`` added as a mandatory arg
       * unused ``*args`` list removed
