fix 404 when page query parameter is empty string (#8578)

* fix 404 when page query parameter is empty string

* Update pagination.py

* Update pagination.py

Co-authored-by: Tom Christie <[email protected]>

Author: shipengtaov

rest_framework/pagination.py

@@ -218,7 +218,7 @@ def paginate_queryset(self, queryset, request, view=None):
         return list(self.page)
 
     def get_page_number(self, request, paginator):
-        page_number = request.query_params.get(self.page_query_param, 1)
+        page_number = request.query_params.get(self.page_query_param) or 1
         if page_number in self.last_page_strings:
             page_number = paginator.num_pages
         return page_number

tests/test_pagination.py

@@ -180,8 +180,9 @@ def get_paginated_content(self, queryset):
     def get_html_context(self):
         return self.pagination.get_html_context()
 
-    def test_no_page_number(self):
-        request = Request(factory.get('/'))
+    @pytest.mark.parametrize('url', ['/', '/?page='])
+    def test_no_page_number(self, url):
+        request = Request(factory.get(url))
         queryset = self.paginate_queryset(request)
         content = self.get_paginated_content(queryset)
         context = self.get_html_context()