Fixed #12241 -- Preserved query strings when using "Save and continue/add another" in admin.

Co-authored-by: Grady Yu <gradyy@users.noreply.github.com>
Co-authored-by: David Sanders <shang.xiao.sanders@gmail.com>
Co-authored-by: Matthew Newton <matthewn@berkeley.edu>

3 files changed, 95 insertions, 4 deletions

diff --git a/django/contrib/admin/options.py b/django/contrib/admin/options.py
index 61ec0a638d..33d55408b0 100644
--- a/django/contrib/admin/options.py
+++ b/django/contrib/admin/options.py
@@ -3,7 +3,9 @@ import enum
 import json
 import re
 from functools import partial, update_wrapper
+from urllib.parse import parse_qsl
 from urllib.parse import quote as urlquote
+from urllib.parse import urlparse
 
 from django import forms
 from django.conf import settings
@@ -1346,12 +1348,17 @@ class ModelAdmin(BaseModelAdmin):
             context,
         )
 
+    def _get_preserved_qsl(self, request, preserved_filters):
+        query_string = urlparse(request.build_absolute_uri()).query
+        return parse_qsl(query_string.replace(preserved_filters, ""))
+
     def response_add(self, request, obj, post_url_continue=None):
         """
         Determine the HttpResponse for the add_view stage.
         """
         opts = obj._meta
         preserved_filters = self.get_preserved_filters(request)
+        preserved_qsl = self._get_preserved_qsl(request, preserved_filters)
         obj_url = reverse(
             "admin:%s_%s_change" % (opts.app_label, opts.model_name),
             args=(quote(obj.pk),),
@@ -1409,7 +1416,11 @@ class ModelAdmin(BaseModelAdmin):
             if post_url_continue is None:
                 post_url_continue = obj_url
             post_url_continue = add_preserved_filters(
-                {"preserved_filters": preserved_filters, "opts": opts},
+                {
+                    "preserved_filters": preserved_filters,
+                    "preserved_qsl": preserved_qsl,
+                    "opts": opts,
+                },
                 post_url_continue,
             )
             return HttpResponseRedirect(post_url_continue)
@@ -1425,7 +1436,12 @@ class ModelAdmin(BaseModelAdmin):
             self.message_user(request, msg, messages.SUCCESS)
             redirect_url = request.path
             redirect_url = add_preserved_filters(
-                {"preserved_filters": preserved_filters, "opts": opts}, redirect_url
+                {
+                    "preserved_filters": preserved_filters,
+                    "preserved_qsl": preserved_qsl,
+                    "opts": opts,
+                },
+                redirect_url,
             )
             return HttpResponseRedirect(redirect_url)
 
@@ -1471,6 +1487,7 @@ class ModelAdmin(BaseModelAdmin):
 
         opts = self.opts
         preserved_filters = self.get_preserved_filters(request)
+        preserved_qsl = self._get_preserved_qsl(request, preserved_filters)
 
         msg_dict = {
             "name": opts.verbose_name,
@@ -1487,7 +1504,12 @@ class ModelAdmin(BaseModelAdmin):
             self.message_user(request, msg, messages.SUCCESS)
             redirect_url = request.path
             redirect_url = add_preserved_filters(
-                {"preserved_filters": preserved_filters, "opts": opts}, redirect_url
+                {
+                    "preserved_filters": preserved_filters,
+                    "preserved_qsl": preserved_qsl,
+                    "opts": opts,
+                },
+                redirect_url,
             )
             return HttpResponseRedirect(redirect_url)
 
@@ -1524,7 +1546,12 @@ class ModelAdmin(BaseModelAdmin):
                 current_app=self.admin_site.name,
             )
             redirect_url = add_preserved_filters(
-                {"preserved_filters": preserved_filters, "opts": opts}, redirect_url
+                {
+                    "preserved_filters": preserved_filters,
+                    "preserved_qsl": preserved_qsl,
+                    "opts": opts,
+                },
+                redirect_url,
             )
             return HttpResponseRedirect(redirect_url)
 
diff --git a/django/contrib/admin/templatetags/admin_urls.py b/django/contrib/admin/templatetags/admin_urls.py
index 13ded03361..871b0d5f20 100644
--- a/django/contrib/admin/templatetags/admin_urls.py
+++ b/django/contrib/admin/templatetags/admin_urls.py
@@ -22,11 +22,15 @@ def admin_urlquote(value):
 def add_preserved_filters(context, url, popup=False, to_field=None):
     opts = context.get("opts")
     preserved_filters = context.get("preserved_filters")
+    preserved_qsl = context.get("preserved_qsl")
 
     parsed_url = list(urlparse(url))
     parsed_qs = dict(parse_qsl(parsed_url[4]))
     merged_qs = {}
 
+    if preserved_qsl:
+        merged_qs.update(preserved_qsl)
+
     if opts and preserved_filters:
         preserved_filters = dict(parse_qsl(preserved_filters))
 
diff --git a/tests/admin_views/tests.py b/tests/admin_views/tests.py
index b2a5fe2ccd..87174dc100 100644
--- a/tests/admin_views/tests.py
+++ b/tests/admin_views/tests.py
@@ -328,6 +328,66 @@ class AdminViewBasicTest(AdminViewBasicTestCase):
             msg_prefix="Couldn't find an input with the right value in the response",
         )
 
+    def test_add_query_string_persists(self):
+        save_options = [
+            {"_addanother": "1"},  # "Save and add another".
+            {"_continue": "1"},  # "Save and continue editing".
+            {"_saveasnew": "1"},  # "Save as new".
+        ]
+        other_options = [
+            "",
+            "_changelist_filters=is_staff__exact%3D0",
+            f"{IS_POPUP_VAR}=1",
+            f"{TO_FIELD_VAR}=id",
+        ]
+        url = reverse("admin:auth_user_add")
+        for i, save_option in enumerate(save_options):
+            for j, other_option in enumerate(other_options):
+                with self.subTest(save_option=save_option, other_option=other_option):
+                    qsl = "username=newuser"
+                    if other_option:
+                        qsl = f"{qsl}&{other_option}"
+                    response = self.client.post(
+                        f"{url}?{qsl}",
+                        {
+                            "username": f"newuser{i}{j}",
+                            "password1": "newpassword",
+                            "password2": "newpassword",
+                            **save_option,
+                        },
+                    )
+                    parsed_url = urlparse(response.url)
+                    self.assertEqual(parsed_url.query, qsl)
+
+    def test_change_query_string_persists(self):
+        save_options = [
+            {"_addanother": "1"},  # "Save and add another".
+            {"_continue": "1"},  # "Save and continue editing".
+        ]
+        other_options = [
+            "",
+            "_changelist_filters=warm%3D1",
+            f"{IS_POPUP_VAR}=1",
+            f"{TO_FIELD_VAR}=id",
+        ]
+        url = reverse("admin:admin_views_color_change", args=(self.color1.pk,))
+        for save_option in save_options:
+            for other_option in other_options:
+                with self.subTest(save_option=save_option, other_option=other_option):
+                    qsl = "value=blue"
+                    if other_option:
+                        qsl = f"{qsl}&{other_option}"
+                    response = self.client.post(
+                        f"{url}?{qsl}",
+                        {
+                            "value": "gold",
+                            "warm": True,
+                            **save_option,
+                        },
+                    )
+                    parsed_url = urlparse(response.url)
+                    self.assertEqual(parsed_url.query, qsl)
+
     def test_basic_edit_GET(self):
         """
         A smoke test to ensure GET on the change_view works.