Fixed #36127 -- Applied default empty display value to links otherwise containing only whitespace in admin.

Author: Antoliny0919

django/contrib/admin/options.py

@@ -22,6 +22,7 @@
 from django.contrib.admin.utils import (
     NestedObjects,
     construct_change_message,
+    display_for_value,
     flatten_fieldsets,
     get_deleted_objects,
     lookup_spawns_duplicates,
@@ -74,6 +75,7 @@
 SOURCE_MODEL_VAR = "_source_model"
 TO_FIELD_VAR = "_to_field"
 IS_FACETS_VAR = "_facets"
+EMPTY_VALUE_STRING = "-"
 
 
 class ShowFacets(enum.Enum):
@@ -1394,10 +1396,13 @@ def response_add(self, request, obj, post_url_continue=None):
             current_app=self.admin_site.name,
         )
         # Add a link to the object's change form if the user can edit the obj.
+        obj_display = display_for_value(str(obj), EMPTY_VALUE_STRING)
         if self.has_change_permission(request, obj):
-            obj_repr = format_html('<a href="{}">{}</a>', urlquote(obj_url), obj)
+            obj_repr = format_html(
+                '<a href="{}">{}</a>', urlquote(obj_url), obj_display
+            )
         else:
-            obj_repr = str(obj)
+            obj_repr = obj_display
         msg_dict = {
             "name": opts.verbose_name,
             "obj": obj_repr,
@@ -1547,9 +1552,12 @@ def response_change(self, request, obj):
         preserved_filters = self.get_preserved_filters(request)
         preserved_qsl = self._get_preserved_qsl(request, preserved_filters)
 
+        obj_display = display_for_value(str(obj), EMPTY_VALUE_STRING)
         msg_dict = {
             "name": opts.verbose_name,
-            "obj": format_html('<a href="{}">{}</a>', urlquote(request.path), obj),
+            "obj": format_html(
+                '<a href="{}">{}</a>', urlquote(request.path), obj_display
+            ),
         }
         if "_continue" in request.POST:
             msg = format_html(
@@ -1728,7 +1736,7 @@ def response_delete(self, request, obj_display, obj_id):
             _("The %(name)s “%(obj)s” was deleted successfully.")
             % {
                 "name": self.opts.verbose_name,
-                "obj": obj_display,
+                "obj": display_for_value(str(obj_display), EMPTY_VALUE_STRING),
             },
             messages.SUCCESS,
         )
@@ -1951,7 +1959,9 @@ def _changeform_view(self, request, object_id, form_url, extra_context):
         context = {
             **self.admin_site.each_context(request),
             "title": title % self.opts.verbose_name,
-            "subtitle": str(obj) if obj else None,
+            "subtitle": (
+                display_for_value(str(obj), EMPTY_VALUE_STRING) if obj else None
+            ),
             "adminform": admin_form,
             "object_id": object_id,
             "original": obj,
@@ -2252,6 +2262,7 @@ def _delete_view(self, request, object_id, extra_context):
             "subtitle": None,
             "object_name": object_name,
             "object": obj,
+            "escaped_object": display_for_value(str(obj), EMPTY_VALUE_STRING),
             "deleted_objects": deleted_objects,
             "model_count": dict(model_count).items(),
             "perms_lacking": perms_needed,
@@ -2300,7 +2311,8 @@ def history_view(self, request, object_id, extra_context=None):
 
         context = {
             **self.admin_site.each_context(request),
-            "title": _("Change history: %s") % obj,
+            "title": _("Change history: %s")
+            % display_for_value(str(obj), EMPTY_VALUE_STRING),
             "subtitle": None,
             "action_list": page_obj,
             "page_range": page_range,

django/contrib/admin/sites.py

@@ -5,6 +5,7 @@
 from django.conf import settings
 from django.contrib.admin import ModelAdmin, actions
 from django.contrib.admin.exceptions import AlreadyRegistered, NotRegistered
+from django.contrib.admin.options import EMPTY_VALUE_STRING
 from django.contrib.admin.views.autocomplete import AutocompleteJsonView
 from django.contrib.auth import REDIRECT_FIELD_NAME
 from django.contrib.auth.decorators import login_not_required
@@ -50,7 +51,7 @@ class AdminSite:
 
     enable_nav_sidebar = True
 
-    empty_value_display = "-"
+    empty_value_display = EMPTY_VALUE_STRING
 
     login_form = None
     index_template = None

django/contrib/admin/templates/admin/auth/user/change_password.html

@@ -1,6 +1,6 @@
 {% extends "admin/base_site.html" %}
 {% load i18n static %}
-{% load admin_urls %}
+{% load admin_urls admin_filters %}
 
 {% block title %}{% if form.errors %}{% translate "Error:" %} {% endif %}{{ block.super }}{% endblock %}
 {% block extrastyle %}
@@ -15,7 +15,7 @@
 <li><a href="{% url 'admin:index' %}">{% translate 'Home' %}</a></li>
 <li><a href="{% url 'admin:app_list' app_label=opts.app_label %}">{{ opts.app_config.verbose_name }}</a></li>
 <li><a href="{% url opts|admin_urlname:'changelist' %}">{{ opts.verbose_name_plural|capfirst }}</a></li>
-<li><a href="{% url opts|admin_urlname:'change' original.pk|admin_urlquote %}">{{ original|truncatewords:"18" }}</a></li>
+<li><a href="{% url opts|admin_urlname:'change' original.pk|admin_urlquote %}">{{ original|to_object_display_value|truncatewords:"18" }}</a></li>
 <li aria-current="page">{% if form.user.has_usable_password %}{% translate 'Change password' %}{% else %}{% translate 'Set password' %}{% endif %}</li>
 </ol>
 {% endblock %}

django/contrib/admin/templates/admin/change_form.html

@@ -1,5 +1,5 @@
 {% extends "admin/base_site.html" %}
-{% load i18n admin_urls static admin_modify %}
+{% load i18n admin_urls static admin_modify admin_filters %}
 
 {% block title %}{% if errors %}{% translate "Error:" %} {% endif %}{{ block.super }}{% endblock %}
 {% block extrahead %}{{ block.super }}
@@ -19,7 +19,7 @@
 <li><a href="{% url 'admin:index' %}">{% translate 'Home' %}</a></li>
 <li><a href="{% url 'admin:app_list' app_label=opts.app_label %}">{{ opts.app_config.verbose_name }}</a></li>
 <li>{% if has_view_permission %}<a href="{% url opts|admin_urlname:'changelist' %}">{{ opts.verbose_name_plural|capfirst }}</a>{% else %}{{ opts.verbose_name_plural|capfirst }}{% endif %}</li>
-<li aria-current="page">{% if add %}{% blocktranslate with name=opts.verbose_name %}Add {{ name }}{% endblocktranslate %}{% else %}{{ original|truncatewords:"18" }}{% endif %}</li>
+<li aria-current="page">{% if add %}{% blocktranslate with name=opts.verbose_name %}Add {{ name }}{% endblocktranslate %}{% else %}{{ original|to_object_display_value|truncatewords:"18" }}{% endif %}</li>
 </ol>
 {% endblock %}
 {% endif %}

django/contrib/admin/templates/admin/delete_confirmation.html

@@ -1,5 +1,5 @@
 {% extends "admin/base_site.html" %}
-{% load i18n admin_urls static %}
+{% load i18n admin_urls static admin_filters %}
 
 {% block extrahead %}
     {{ block.super }}
@@ -14,25 +14,25 @@
 <li><a href="{% url 'admin:index' %}">{% translate 'Home' %}</a></li>
 <li><a href="{% url 'admin:app_list' app_label=opts.app_label %}">{{ opts.app_config.verbose_name }}</a></li>
 <li><a href="{% url opts|admin_urlname:'changelist' %}">{{ opts.verbose_name_plural|capfirst }}</a></li>
-<li><a href="{% url opts|admin_urlname:'change' object.pk|admin_urlquote %}">{{ object|truncatewords:"18" }}</a></li>
+<li><a href="{% url opts|admin_urlname:'change' object.pk|admin_urlquote %}">{{ object|to_object_display_value|truncatewords:"18" }}</a></li>
 <li aria-current="page">{% translate 'Delete' %}</li>
 </ol>
 {% endblock %}
 
 {% block content %}
 {% if perms_lacking %}
   {% block delete_forbidden %}
-    <p>{% blocktranslate with escaped_object=object %}Deleting the {{ object_name }} “{{ escaped_object }}” would result in deleting related objects, but your account doesn't have permission to delete the following types of objects:{% endblocktranslate %}</p>
+    <p>{% blocktranslate %}Deleting the {{ object_name }} “{{ escaped_object }}” would result in deleting related objects, but your account doesn't have permission to delete the following types of objects:{% endblocktranslate %}</p>
     <ul id="deleted-objects">{{ perms_lacking|unordered_list }}</ul>
   {% endblock %}
 {% elif protected %}
   {% block delete_protected %}
-    <p>{% blocktranslate with escaped_object=object %}Deleting the {{ object_name }} “{{ escaped_object }}” would require deleting the following protected related objects:{% endblocktranslate %}</p>
+    <p>{% blocktranslate %}Deleting the {{ object_name }} “{{ escaped_object }}” would require deleting the following protected related objects:{% endblocktranslate %}</p>
     <ul id="deleted-objects">{{ protected|unordered_list }}</ul>
   {% endblock %}
 {% else %}
   {% block delete_confirm %}
-    <p>{% blocktranslate with escaped_object=object %}Are you sure you want to delete the {{ object_name }} “{{ escaped_object }}”? All of the following related items will be deleted:{% endblocktranslate %}</p>
+    <p>{% blocktranslate %}Are you sure you want to delete the {{ object_name }} “{{ escaped_object }}”? All of the following related items will be deleted:{% endblocktranslate %}</p>
     {% include "admin/includes/object_delete_summary.html" %}
     <h2>{% translate "Objects" %}</h2>
     <ul id="deleted-objects">{{ deleted_objects|unordered_list }}</ul>

django/contrib/admin/templates/admin/index.html

@@ -1,5 +1,5 @@
 {% extends "admin/base_site.html" %}
-{% load i18n static %}
+{% load i18n static admin_filters %}
 
 {% block extrastyle %}{{ block.super }}<link rel="stylesheet" href="{% static "admin/css/dashboard.css" %}">{% endblock %}
 
@@ -32,9 +32,9 @@ <h3>{% translate 'My actions' %}</h3>
             <li class="{% if entry.is_addition %}addlink{% endif %}{% if entry.is_change %}changelink{% endif %}{% if entry.is_deletion %}deletelink{% endif %}">
                 <span class="visually-hidden">{% if entry.is_addition %}{% translate 'Added:' %}{% elif entry.is_change %}{% translate 'Changed:' %}{% elif entry.is_deletion %}{% translate 'Deleted:' %}{% endif %}</span>
                 {% if entry.is_deletion or not entry.get_admin_url %}
-                    {{ entry.object_repr }}
+                    {{ entry.object_repr|to_object_display_value }}
                 {% else %}
-                    <a href="{{ entry.get_admin_url }}">{{ entry.object_repr }}</a>
+                    <a href="{{ entry.get_admin_url }}">{{ entry.object_repr|to_object_display_value }}</a>
                 {% endif %}
                 <br>
                 {% if entry.content_type %}

django/contrib/admin/templates/admin/object_history.html

@@ -1,12 +1,12 @@
 {% extends "admin/base_site.html" %}
-{% load i18n admin_urls %}
+{% load i18n admin_urls admin_filters %}
 
 {% block breadcrumbs %}
 <ol class="breadcrumbs">
 <li><a href="{% url 'admin:index' %}">{% translate 'Home' %}</a></li>
 <li><a href="{% url 'admin:app_list' app_label=opts.app_label %}">{{ opts.app_config.verbose_name }}</a></li>
 <li><a href="{% url opts|admin_urlname:'changelist' %}">{{ module_name }}</a></li>
-<li><a href="{% url opts|admin_urlname:'change' object.pk|admin_urlquote %}">{{ object|truncatewords:"18" }}</a></li>
+<li><a href="{% url opts|admin_urlname:'change' object.pk|admin_urlquote %}">{{ object|to_object_display_value|truncatewords:"18" }}</a></li>
 <li aria-current="page">{% translate 'History' %}</li>
 </ol>
 {% endblock %}

django/contrib/admin/templatetags/admin_filters.py

@@ -0,0 +1,12 @@
+from django import template
+from django.contrib.admin.options import EMPTY_VALUE_STRING
+from django.contrib.admin.utils import display_for_value
+from django.template.defaultfilters import stringfilter
+
+register = template.Library()
+
+
+@register.filter
+@stringfilter
+def to_object_display_value(value):
+    return display_for_value(str(value), EMPTY_VALUE_STRING)

django/contrib/admin/templatetags/admin_list.py

@@ -226,8 +226,6 @@ def link_in_col(is_first, field_name, cl):
             empty_value_display = getattr(
                 attr, "empty_value_display", empty_value_display
             )
-            if isinstance(value, str) and value.strip() == "":
-                value = ""
             if f is None or f.auto_created:
                 if field_name == "action_checkbox":
                     row_classes = ["action-checkbox"]

django/contrib/admin/utils.py

@@ -18,6 +18,7 @@
 from django.utils.hashable import make_hashable
 from django.utils.html import format_html
 from django.utils.regex_helper import _lazy_re_compile
+from django.utils.safestring import SafeString
 from django.utils.text import capfirst
 from django.utils.translation import ngettext
 from django.utils.translation import override as translation_override
@@ -131,6 +132,8 @@ def get_deleted_objects(objs, request, admin_site):
     Return a nested list of strings suitable for display in the
     template with the ``unordered_list`` filter.
     """
+    from django.contrib.admin.options import EMPTY_VALUE_STRING
+
     try:
         obj = objs[0]
     except IndexError:
@@ -164,8 +167,12 @@ def format_callback(obj):
                 return no_edit_link
 
             # Display a link to the admin page.
+            obj_display = display_for_value(str(obj), EMPTY_VALUE_STRING)
             return format_html(
-                '{}: <a href="{}">{}</a>', capfirst(opts.verbose_name), admin_url, obj
+                '{}: <a href="{}">{}</a>',
+                capfirst(opts.verbose_name),
+                admin_url,
+                obj_display,
             )
         else:
             # Don't display link to edit, because it either has no
@@ -468,7 +475,9 @@ def display_for_value(value, empty_value_display, boolean=False):
 
     if boolean:
         return _boolean_icon(value)
-    elif value in EMPTY_VALUES:
+    if isinstance(value, str) and not isinstance(value, SafeString):
+        value = value.strip()
+    if value in EMPTY_VALUES:
         return empty_value_display
     elif isinstance(value, bool):
         return str(value)