Fixed #17856 -- Passed obj to get_inline_instances

Thanks ybon, quinode and sjaensch for the patch, and Tim Graham
for the review.

django/contrib/admin/options.py

@@ -346,14 +346,14 @@ class ModelAdmin(BaseModelAdmin):
         self.admin_site = admin_site
         super(ModelAdmin, self).__init__()
 
-    def get_inline_instances(self, request):
+    def get_inline_instances(self, request, obj=None):
         inline_instances = []
         for inline_class in self.inlines:
             inline = inline_class(self.model, self.admin_site)
             if request:
                 if not (inline.has_add_permission(request) or
-                        inline.has_change_permission(request) or
-                        inline.has_delete_permission(request)):
+                        inline.has_change_permission(request, obj) or
+                        inline.has_delete_permission(request, obj)):
                     continue
                 if not inline.has_add_permission(request):
                     inline.max_num = 0
@@ -506,7 +506,7 @@ class ModelAdmin(BaseModelAdmin):
             fields=self.list_editable, **defaults)
 
     def get_formsets(self, request, obj=None):
-        for inline in self.get_inline_instances(request):
+        for inline in self.get_inline_instances(request, obj):
             yield inline.get_formset(request, obj)
 
     def get_paginator(self, request, queryset, per_page, orphans=0, allow_empty_first_page=True):
@@ -994,7 +994,7 @@ class ModelAdmin(BaseModelAdmin):
 
         ModelForm = self.get_form(request)
         formsets = []
-        inline_instances = self.get_inline_instances(request)
+        inline_instances = self.get_inline_instances(request, None)
         if request.method == 'POST':
             form = ModelForm(request.POST, request.FILES)
             if form.is_valid():
@@ -1091,7 +1091,7 @@ class ModelAdmin(BaseModelAdmin):
 
         ModelForm = self.get_form(request, obj)
         formsets = []
-        inline_instances = self.get_inline_instances(request)
+        inline_instances = self.get_inline_instances(request, obj)
         if request.method == 'POST':
             form = ModelForm(request.POST, request.FILES, instance=obj)
             if form.is_valid():

docs/ref/contrib/admin/index.txt

@@ -1046,6 +1046,16 @@ templates used by the :class:`ModelAdmin` views:
     changelist that will be linked to the change view, as described in the
     :attr:`ModelAdmin.list_display_links` section.
 
+.. method:: ModelAdmin.get_inline_instances(self, request, obj=None)
+
+    .. versionadded:: 1.5
+
+    The ``get_inline_instances`` method is given the ``HttpRequest`` and the
+    ``obj`` being edited (or ``None`` on an add form) and is expected to return
+    a ``list`` or ``tuple`` of :class:`~django.contrib.admin.InlineModelAdmin`
+    objects, as described below in the :class:`~django.contrib.admin.InlineModelAdmin`
+    section.
+
 .. method:: ModelAdmin.get_urls(self)
 
     The ``get_urls`` method on a ``ModelAdmin`` returns the URLs to be used for