Fixed #6412 -- More details if a template file cannot be loaded

Report more details about template files in loader postmortem.

django/views/debug.py

@@ -218,6 +218,15 @@ class ExceptionReporter(object):
             self.exc_value = Exception('Deprecated String Exception: %r' % self.exc_type)
             self.exc_type = type(self.exc_value)
 
+    def format_path_status(self, path):
+        if not os.path.exists(path):
+            return "File does not exist"
+        if not os.path.isfile(path):
+            return "Not a file"
+        if not os.access(path, os.R_OK):
+            return "File is not readable"
+        return "File exists"
+
     def get_traceback_data(self):
         "Return a Context instance containing traceback information."
 
@@ -230,8 +239,10 @@ class ExceptionReporter(object):
                     source_list_func = loader.get_template_sources
                     # NOTE: This assumes exc_value is the name of the template that
                     # the loader attempted to load.
-                    template_list = [{'name': t, 'exists': os.path.exists(t)} \
-                        for t in source_list_func(str(self.exc_value))]
+                    template_list = [{
+                        'name': t,
+                        'status': self.format_path_status(t),
+                    } for t in source_list_func(str(self.exc_value))]
                 except AttributeError:
                     template_list = []
                 loader_name = loader.__module__ + '.' + loader.__class__.__name__
@@ -650,7 +661,9 @@ TECHNICAL_500_TEMPLATE = """
         <ul>
         {% for loader in loader_debug_info %}
             <li>Using loader <code>{{ loader.loader }}</code>:
-                <ul>{% for t in loader.templates %}<li><code>{{ t.name }}</code> (File {% if t.exists %}exists{% else %}does not exist{% endif %})</li>{% endfor %}</ul>
+                <ul>
+                {% for t in loader.templates %}<li><code>{{ t.name }}</code> ({{ t.status }})</li>{% endfor %}
+                </ul>
             </li>
         {% endfor %}
         </ul>
@@ -753,7 +766,7 @@ Installed Middleware:
 {% if template_does_not_exist %}Template Loader Error:
 {% if loader_debug_info %}Django tried loading these templates, in this order:
 {% for loader in loader_debug_info %}Using loader {{ loader.loader }}:
-{% for t in loader.templates %}{{ t.name }} (File {% if t.exists %}exists{% else %}does not exist{% endif %})
+{% for t in loader.templates %}{{ t.name }} ({{ t.status }})
 {% endfor %}{% endfor %}
 {% else %}Django couldn't find any templates because your TEMPLATE_LOADERS setting is empty!
 {% endif %}
@@ -943,7 +956,7 @@ Installed Middleware:
 {% if template_does_not_exist %}Template loader Error:
 {% if loader_debug_info %}Django tried loading these templates, in this order:
 {% for loader in loader_debug_info %}Using loader {{ loader.loader }}:
-{% for t in loader.templates %}{{ t.name }} (File {% if t.exists %}exists{% else %}does not exist{% endif %})
+{% for t in loader.templates %}{{ t.name }} ({{ t.status }})
 {% endfor %}{% endfor %}
 {% else %}Django couldn't find any templates because your TEMPLATE_LOADERS setting is empty!
 {% endif %}

tests/view_tests/tests/test_debug.py

@@ -5,8 +5,9 @@ from __future__ import absolute_import, unicode_literals
 
 import inspect
 import os
+import shutil
 import sys
-import tempfile
+from tempfile import NamedTemporaryFile, mkdtemp, mkstemp
 
 from django.core import mail
 from django.core.files.uploadedfile import SimpleUploadedFile
@@ -21,6 +22,7 @@ from .. import BrokenException, except_args
 from ..views import (sensitive_view, non_sensitive_view, paranoid_view,
     custom_exception_reporter_filter_view, sensitive_method_view,
     sensitive_args_function_caller, sensitive_kwargs_function_caller)
+from django.utils.unittest import skipIf
 
 
 @override_settings(DEBUG=True, TEMPLATE_DEBUG=True)
@@ -78,9 +80,38 @@ class DebugViewTests(TestCase):
                         raising_loc)
 
     def test_template_loader_postmortem(self):
-        response = self.client.get(reverse('raises_template_does_not_exist'))
-        template_path = os.path.join('templates', 'i_dont_exist.html')
-        self.assertContains(response, template_path, status_code=500)
+        """Tests for not existing file"""
+        template_name = "notfound.html"
+        with NamedTemporaryFile(prefix=template_name) as tempfile:
+            tempdir = os.path.dirname(tempfile.name)
+            template_path = os.path.join(tempdir, template_name)
+            with override_settings(TEMPLATE_DIRS=(tempdir,)):
+                response = self.client.get(reverse('raises_template_does_not_exist', kwargs={"path": template_name}))
+            self.assertContains(response, "%s (File does not exist)" % template_path, status_code=500, count=1)
+
+    @skipIf(sys.platform == "win32", "Python on Windows doesn't have working os.chmod() and os.access().")
+    def test_template_loader_postmortem_notreadable(self):
+        """Tests for not readable file"""
+        with NamedTemporaryFile() as tempfile:
+            template_name = tempfile.name
+            tempdir = os.path.dirname(tempfile.name)
+            template_path = os.path.join(tempdir, template_name)
+            os.chmod(template_path, 0o0222)
+            with override_settings(TEMPLATE_DIRS=(tempdir,)):
+                response = self.client.get(reverse('raises_template_does_not_exist', kwargs={"path": template_name}))
+            self.assertContains(response, "%s (File is not readable)" % template_path, status_code=500, count=1)
+
+    def test_template_loader_postmortem_notafile(self):
+        """Tests for not being a file"""
+        try:
+            template_path = mkdtemp()
+            template_name = os.path.basename(template_path)
+            tempdir = os.path.dirname(template_path)
+            with override_settings(TEMPLATE_DIRS=(tempdir,)):
+                response = self.client.get(reverse('raises_template_does_not_exist', kwargs={"path": template_name}))
+            self.assertContains(response, "%s (Not a file)" % template_path, status_code=500, count=1)
+        finally:
+            shutil.rmtree(template_path)
 
 
 class ExceptionReporterTests(TestCase):
@@ -129,7 +160,7 @@ class ExceptionReporterTests(TestCase):
         reporter = ExceptionReporter(None, None, None, None)
 
         for newline in ['\n', '\r\n', '\r']:
-            fd,filename = tempfile.mkstemp(text = False)
+            fd, filename = mkstemp(text=False)
             os.write(fd, force_bytes(newline.join(LINES)+newline))
             os.close(fd)
 

tests/view_tests/urls.py

@@ -66,5 +66,5 @@ urlpatterns = patterns('',
 urlpatterns += patterns('view_tests.views',
     url(r'view_exception/(?P<n>\d+)/$', 'view_exception', name='view_exception'),
     url(r'template_exception/(?P<n>\d+)/$', 'template_exception', name='template_exception'),
-    url(r'^raises_template_does_not_exist/$', 'raises_template_does_not_exist', name='raises_template_does_not_exist'),
+    url(r'^raises_template_does_not_exist/(?P<path>.+)$', 'raises_template_does_not_exist', name='raises_template_does_not_exist'),
 )

tests/view_tests/views.py

@@ -112,11 +112,11 @@ def render_view_with_current_app_conflict(request):
         'bar': 'BAR',
     }, current_app="foobar_app", context_instance=RequestContext(request))
 
-def raises_template_does_not_exist(request):
+def raises_template_does_not_exist(request, path='i_dont_exist.html'):
     # We need to inspect the HTML generated by the fancy 500 debug view but
     # the test client ignores it, so we send it explicitly.
     try:
-        return render_to_response('i_dont_exist.html')
+        return render_to_response(path)
     except TemplateDoesNotExist:
         return technical_500_response(request, *sys.exc_info())