Pass all URL parameters to page chooser search action, including multiple and user_perms

wagtail/admin/templates/wagtailadmin/chooser/browse.html

@@ -5,7 +5,8 @@
     {% trans "Choose a page" as choose_str %}
 {% endif %}
 
-{% include "wagtailadmin/shared/header.html" with title=choose_str subtitle=page_type_names|join:", " search_url="wagtailadmin_choose_page_search" query_parameters="page_type="|add:page_type_string icon="doc-empty-inverse" search_disable_async=True %}
+{% querystring as search_query_params %}
+{% include "wagtailadmin/shared/header.html" with title=choose_str subtitle=page_type_names|join:", " search_url="wagtailadmin_choose_page_search" query_parameters=search_query_params icon="doc-empty-inverse" search_disable_async=True %}
 
 <div class="nice-padding">
     {% include 'wagtailadmin/chooser/_link_types.html' with current='internal' %}

wagtail/admin/templates/wagtailadmin/shared/header.html

@@ -11,7 +11,7 @@
     - `search_results_url` - URL to be used for async requests to search results, if not provided, the form's action URL will be used
     - `search_target` - A selector string to be used as the target for the search results to be swapped into. Defaults to '#listing-results'
     - `search_disable_async` - If True, the default header async search functionality will not be used
-    - `query_parameters` - a query string (without the '?') to be placed after the search URL
+    - `query_parameters` - a query string (with or without the '?') to be placed after the search URL
     - `icon` - name of an icon to place against the title
     - `merged` - if true, add the classname 'w-header--merged'
     - `action_url` - if present, display an 'action' button. This is the URL to be used as the link URL for the button
@@ -42,7 +42,7 @@
             {% if search_url %}
                 <form
                     class="col search-form"
-                    action="{% url search_url %}{% if query_parameters %}?{{ query_parameters }}{% endif %}"
+                    action="{% url search_url %}{% if query_parameters %}{% if query_parameters.0 != '?' %}?{% endif %}{{ query_parameters }}{% endif %}"
                     method="get"
                     novalidate
                     role="search"

wagtail/admin/tests/test_page_chooser.py

@@ -65,12 +65,20 @@ class TestChooserBrowse(WagtailTestUtils, TestCase):
 
         checkbox_value = str(self.child_page.id)
         decoded_content = response.content.decode()
+        response_json = json.loads(decoded_content)
+        self.assertEqual(response_json["step"], "browse")
+        response_html = response_json["html"]
 
-        self.assertIn(f'value=\\"{checkbox_value}\\"', decoded_content)
+        self.assertIn(f'value="{checkbox_value}"', response_html)
 
         self.assertEqual(response.status_code, 200)
         self.assertTemplateUsed(response, "wagtailadmin/chooser/browse.html")
 
+        soup = self.get_soup(response_html)
+        search_url = soup.find("form", role="search")["action"]
+        search_query_params = parse_qs(urlsplit(search_url).query)
+        self.assertEqual(search_query_params["multiple"], ["1"])
+
     @override_settings(USE_THOUSAND_SEPARATOR=False)
     def test_multiple_chooser_view_without_thousand_separator(self):
         self.page = Page.objects.get(id=1)