Fixed #16117 -- Added decorators for admin action and display functions.

Refs #25134, #32099.

4 files changed, 85 insertions, 10 deletions

diff --git a/django/contrib/admin/__init__.py b/django/contrib/admin/__init__.py
index 0bcee1a578..975cf053aa 100644
--- a/django/contrib/admin/__init__.py
+++ b/django/contrib/admin/__init__.py
@@ -1,4 +1,4 @@
-from django.contrib.admin.decorators import register
+from django.contrib.admin.decorators import action, display, register
 from django.contrib.admin.filters import (
     AllValuesFieldListFilter, BooleanFieldListFilter, ChoicesFieldListFilter,
     DateFieldListFilter, EmptyFieldListFilter, FieldListFilter, ListFilter,
@@ -11,10 +11,10 @@ from django.contrib.admin.sites import AdminSite, site
 from django.utils.module_loading import autodiscover_modules
 
 __all__ = [
-    "register", "ModelAdmin", "HORIZONTAL", "VERTICAL", "StackedInline",
-    "TabularInline", "AdminSite", "site", "ListFilter", "SimpleListFilter",
-    "FieldListFilter", "BooleanFieldListFilter", "RelatedFieldListFilter",
-    "ChoicesFieldListFilter", "DateFieldListFilter",
+    "action", "display", "register", "ModelAdmin", "HORIZONTAL", "VERTICAL",
+    "StackedInline", "TabularInline", "AdminSite", "site", "ListFilter",
+    "SimpleListFilter", "FieldListFilter", "BooleanFieldListFilter",
+    "RelatedFieldListFilter", "ChoicesFieldListFilter", "DateFieldListFilter",
     "AllValuesFieldListFilter", "EmptyFieldListFilter",
     "RelatedOnlyFieldListFilter", "autodiscover",
 ]
diff --git a/django/contrib/admin/actions.py b/django/contrib/admin/actions.py
index 1e1c3bd384..665d83c7f7 100644
--- a/django/contrib/admin/actions.py
+++ b/django/contrib/admin/actions.py
@@ -4,12 +4,17 @@ Built-in, globally-available admin actions.
 
 from django.contrib import messages
 from django.contrib.admin import helpers
+from django.contrib.admin.decorators import action
 from django.contrib.admin.utils import model_ngettext
 from django.core.exceptions import PermissionDenied
 from django.template.response import TemplateResponse
 from django.utils.translation import gettext as _, gettext_lazy
 
 
+@action(
+    permissions=['delete'],
+    description=gettext_lazy('Delete selected %(verbose_name_plural)s'),
+)
 def delete_selected(modeladmin, request, queryset):
     """
     Default action which deletes the selected objects.
@@ -73,7 +78,3 @@ def delete_selected(modeladmin, request, queryset):
         "admin/%s/delete_selected_confirmation.html" % app_label,
         "admin/delete_selected_confirmation.html"
     ], context)
-
-
-delete_selected.allowed_permissions = ('delete',)
-delete_selected.short_description = gettext_lazy("Delete selected %(verbose_name_plural)s")
diff --git a/django/contrib/admin/decorators.py b/django/contrib/admin/decorators.py
index 1c43c9505c..4de99580ad 100644
--- a/django/contrib/admin/decorators.py
+++ b/django/contrib/admin/decorators.py
@@ -1,3 +1,76 @@
+def action(function=None, *, permissions=None, description=None):
+    """
+    Conveniently add attributes to an action function::
+
+        @admin.action(
+            permissions=['publish'],
+            description='Mark selected stories as published',
+        )
+        def make_published(self, request, queryset):
+            queryset.update(status='p')
+
+    This is equivalent to setting some attributes (with the original, longer
+    names) on the function directly::
+
+        def make_published(self, request, queryset):
+            queryset.update(status='p')
+        make_published.allowed_permissions = ['publish']
+        make_published.short_description = 'Mark selected stories as published'
+    """
+    def decorator(func):
+        if permissions is not None:
+            func.allowed_permissions = permissions
+        if description is not None:
+            func.short_description = description
+        return func
+    if function is None:
+        return decorator
+    else:
+        return decorator(function)
+
+
+def display(function=None, *, boolean=None, ordering=None, description=None, empty_value=None):
+    """
+    Conveniently add attributes to a display function::
+
+        @admin.display(
+            boolean=True,
+            ordering='-publish_date',
+            description='Is Published?',
+        )
+        def is_published(self, obj):
+            return obj.publish_date is not None
+
+    This is equivalent to setting some attributes (with the original, longer
+    names) on the function directly::
+
+        def is_published(self, obj):
+            return obj.publish_date is not None
+        is_published.boolean = True
+        is_published.admin_order_field = '-publish_date'
+        is_published.short_description = 'Is Published?'
+    """
+    def decorator(func):
+        if boolean is not None and empty_value is not None:
+            raise ValueError(
+                'The boolean and empty_value arguments to the @display '
+                'decorator are mutually exclusive.'
+            )
+        if boolean is not None:
+            func.boolean = boolean
+        if ordering is not None:
+            func.admin_order_field = ordering
+        if description is not None:
+            func.short_description = description
+        if empty_value is not None:
+            func.empty_value_display = empty_value
+        return func
+    if function is None:
+        return decorator
+    else:
+        return decorator(function)
+
+
 def register(*models, site=None):
     """
     Register the given model(s) classes and wrapped ModelAdmin class with
diff --git a/django/contrib/admin/options.py b/django/contrib/admin/options.py
index 5214a266e3..6b0982eab8 100644
--- a/django/contrib/admin/options.py
+++ b/django/contrib/admin/options.py
@@ -12,6 +12,7 @@ from django.contrib.admin import helpers, widgets
 from django.contrib.admin.checks import (
     BaseModelAdminChecks, InlineModelAdminChecks, ModelAdminChecks,
 )
+from django.contrib.admin.decorators import display
 from django.contrib.admin.exceptions import DisallowedModelAdminToField
 from django.contrib.admin.templatetags.admin_urls import add_preserved_filters
 from django.contrib.admin.utils import (
@@ -848,12 +849,12 @@ class ModelAdmin(BaseModelAdmin):
             action_flag=DELETION,
         )
 
+    @display(description=mark_safe('<input type="checkbox" id="action-toggle">'))
     def action_checkbox(self, obj):
         """
         A list_display column containing a checkbox widget.
         """
         return helpers.checkbox.render(helpers.ACTION_CHECKBOX_NAME, str(obj.pk))
-    action_checkbox.short_description = mark_safe('<input type="checkbox" id="action-toggle">')
 
     @staticmethod
     def _get_action_description(func, name):