From 5ce237e00471d885f05e6d979ec777552809b3b1 Mon Sep 17 00:00:00 2001
From: Dhaval Mehta <20968146+dhaval-mehta@users.noreply.github.com>
Date: Sun, 28 Jun 2020 17:58:59 +0530
Subject: [PATCH] Corrected regex serialization for OpenAPI.  (#7389)

* replace \Z by \z in regex

* fix test cases for Django >= 3.0

* fix isort

* Added comment for why `\z`.

Co-authored-by: Carlton Gibson <carlton@noumenal.es>
---
 rest_framework/schemas/openapi.py | 4 +++-
 tests/schemas/test_openapi.py     | 1 +
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/rest_framework/schemas/openapi.py b/rest_framework/schemas/openapi.py
index 9b3082822..9774a94c7 100644
--- a/rest_framework/schemas/openapi.py
+++ b/rest_framework/schemas/openapi.py
@@ -554,7 +554,9 @@ class AutoSchema(ViewInspector):
             if isinstance(v, URLValidator):
                 schema['format'] = 'uri'
             if isinstance(v, RegexValidator):
-                schema['pattern'] = v.regex.pattern
+                # In Python, the token \Z does what \z does in other engines.
+                # https://stackoverflow.com/questions/53283160
+                schema['pattern'] = v.regex.pattern.replace('\\Z', '\\z')
             elif isinstance(v, MaxLengthValidator):
                 attr_name = 'maxLength'
                 if isinstance(field, serializers.ListField):
diff --git a/tests/schemas/test_openapi.py b/tests/schemas/test_openapi.py
index 0e86a7f50..d483f3d45 100644
--- a/tests/schemas/test_openapi.py
+++ b/tests/schemas/test_openapi.py
@@ -855,6 +855,7 @@ class TestOperationIntrospection(TestCase):
         assert properties['url']['type'] == 'string'
         assert properties['url']['nullable'] is True
         assert properties['url']['default'] == 'http://www.example.com'
+        assert '\\Z' not in properties['url']['pattern']
 
         assert properties['uuid']['type'] == 'string'
         assert properties['uuid']['format'] == 'uuid'