From 0fe0e1e7038e74f071e93a77bd5900dc191b086d Mon Sep 17 00:00:00 2001
From: Tom Christie <tom@tomchristie.com>
Date: Fri, 21 Oct 2016 16:59:34 +0100
Subject: [PATCH] Fix schema base paths (#4611)

---
 rest_framework/schemas.py | 15 +++++++++++++--
 tests/test_schemas.py     | 11 +++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/rest_framework/schemas.py b/rest_framework/schemas.py
index af861426c1..9b9984699c 100644
--- a/rest_framework/schemas.py
+++ b/rest_framework/schemas.py
@@ -1,4 +1,3 @@
-import os
 import re
 from collections import OrderedDict
 from importlib import import_module
@@ -37,6 +36,18 @@
 })
 
 
+def common_path(paths):
+    split_paths = [path.strip('/').split('/') for path in paths]
+    s1 = min(split_paths)
+    s2 = max(split_paths)
+    common = s1
+    for i, c in enumerate(s1):
+        if c != s2[i]:
+            common = s1[:i]
+            break
+    return '/' + '/'.join(common)
+
+
 def get_pk_name(model):
     meta = model._meta.concrete_model._meta
     return _get_pk(meta).name
@@ -292,7 +303,7 @@ def determine_path_prefix(self, paths):
                 # one URL that doesn't have a path prefix.
                 return '/'
             prefixes.append('/' + prefix + '/')
-        return os.path.commonprefix(prefixes)
+        return common_path(prefixes)
 
     def create_view(self, callback, method, request=None):
         """
diff --git a/tests/test_schemas.py b/tests/test_schemas.py
index 7188087c4e..80b456ea07 100644
--- a/tests/test_schemas.py
+++ b/tests/test_schemas.py
@@ -335,3 +335,14 @@ def test_schema_for_regular_views(self):
             }
         )
         self.assertEqual(schema, expected)
+
+
+@unittest.skipUnless(coreapi, 'coreapi is not installed')
+class Test4605Regression(TestCase):
+    def test_4605_regression(self):
+        generator = SchemaGenerator()
+        prefix = generator.determine_path_prefix([
+            '/api/v1/items/',
+            '/auth/convert-token/'
+        ])
+        assert prefix == '/'