Fixed #27991 -- Added obj arg to InlineModelAdmin.has_add_permission().

Thanks Vladimir Ivanov for the initial patch.

docs/internals/deprecation.txt

@@ -41,6 +41,9 @@ details on these changes.
 
 * ``django.contrib.staticfiles.templatetags.static()`` will be removed.
 
+* The shim to allow ``InlineModelAdmin.has_add_permission()`` to be defined
+  without an ``obj`` argument will be removed.
+
 .. _deprecation-removed-in-2.1:
 
 2.1

docs/ref/contrib/admin/index.txt

@@ -2395,10 +2395,15 @@ The ``InlineModelAdmin`` class adds or customizes:
     inline forms. For example, this may be based on the model instance
     (passed as the keyword argument ``obj``).
 
-.. method:: InlineModelAdmin.has_add_permission(request)
+.. method:: InlineModelAdmin.has_add_permission(request, obj)
 
     Should return ``True`` if adding an inline object is permitted, ``False``
-    otherwise.
+    otherwise. ``obj`` is the parent object being edited or ``None`` when
+    adding a new parent.
+
+    .. versionchanged:: 2.1
+
+        The ``obj`` argument was added.
 
 .. method:: InlineModelAdmin.has_change_permission(request, obj=None)
 

docs/releases/2.1.txt

@@ -64,6 +64,9 @@ Minor features
   with ``change_list_object_tools.html`` and
   ``change_form_object_tools.html`` templates.
 
+* :meth:`.InlineModelAdmin.has_add_permission` is now passed the parent object
+  as the second positional argument, ``obj``.
+
 :mod:`django.contrib.admindocs`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -398,6 +401,10 @@ Miscellaneous
 * ``django.contrib.staticfiles.templatetags.static()`` is deprecated in favor
   of ``django.templatetags.static.static()``.
 
+* Support for :meth:`.InlineModelAdmin.has_add_permission` methods that don't
+  accept ``obj`` as the second positional argument will be removed in Django
+  3.0.
+
 .. _removed-features-2.1:
 
 Features removed in 2.1