From 043383e3f31955c493517cb5b12dd538c02f5246 Mon Sep 17 00:00:00 2001
From: Berker Peksag <berker.peksag@gmail.com>
Date: Sun, 14 Feb 2016 23:28:26 +0200
Subject: [PATCH] Fixed #24727 -- Prevented ClearableFileInput from masking
 exceptions on Python 2

---
 django/forms/widgets.py                       |  2 +-
 .../widget_tests/test_clearablefileinput.py   | 39 +++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/django/forms/widgets.py b/django/forms/widgets.py
index 3d7f711056..f48f84dfa8 100644
--- a/django/forms/widgets.py
+++ b/django/forms/widgets.py
@@ -372,7 +372,7 @@ class ClearableFileInput(FileInput):
         """
         Return whether value is considered to be initial value.
         """
-        return bool(value and hasattr(value, 'url'))
+        return bool(value and getattr(value, 'url', False))
 
     def get_template_substitution_values(self, value):
         """
diff --git a/tests/forms_tests/widget_tests/test_clearablefileinput.py b/tests/forms_tests/widget_tests/test_clearablefileinput.py
index 4982a6e570..5c093dbd46 100644
--- a/tests/forms_tests/widget_tests/test_clearablefileinput.py
+++ b/tests/forms_tests/widget_tests/test_clearablefileinput.py
@@ -105,3 +105,42 @@ class ClearableFileInputTest(WidgetTest):
             name='myfile',
         )
         self.assertEqual(value, field)
+
+    def test_html_does_not_mask_exceptions(self):
+        """
+        A ClearableFileInput should not mask exceptions produced while
+        checking that it has a value.
+        """
+        @python_2_unicode_compatible
+        class FailingURLFieldFile(object):
+            @property
+            def url(self):
+                raise ValueError('Canary')
+
+            def __str__(self):
+                return 'value'
+
+        with self.assertRaisesMessage(ValueError, 'Canary'):
+            self.widget.render('myfile', FailingURLFieldFile())
+
+    def test_url_as_property(self):
+        @python_2_unicode_compatible
+        class URLFieldFile(object):
+            @property
+            def url(self):
+                return 'https://www.python.org/'
+
+            def __str__(self):
+                return 'value'
+
+        html = self.widget.render('myfile', URLFieldFile())
+        self.assertInHTML('<a href="https://www.python.org/">value</a>', html)
+
+    def test_return_false_if_url_does_not_exists(self):
+        @python_2_unicode_compatible
+        class NoURLFieldFile(object):
+            def __str__(self):
+                return 'value'
+
+        html = self.widget.render('myfile', NoURLFieldFile())
+        self.assertHTMLEqual(html, '<input name="myfile" type="file" />')