Fixed #24399 -- Made filesystem loaders use more specific exceptions.

django/template/loaders/filesystem.py

@@ -2,6 +2,7 @@
 Wrapper for loading templates from the filesystem.
 """
 
+import errno
 import io
 
 from django.core.exceptions import SuspiciousFileOperation
@@ -37,6 +38,7 @@ def load_template_source(self, template_name, template_dirs=None):
             try:
                 with io.open(filepath, encoding=self.engine.file_charset) as fp:
                     return fp.read(), filepath
-            except IOError:
-                pass
+            except IOError as e:
+                if e.errno != errno.ENOENT:
+                    raise
         raise TemplateDoesNotExist(template_name)

django/views/debug.py

@@ -269,10 +269,6 @@ def __init__(self, request, exc_type, exc_value, tb, is_email=False):
     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):

docs/releases/1.9.txt

@@ -224,6 +224,19 @@ the keyword argument ``clear=True``.
 assignment for many-to-many relations and as a consequence now use the new
 behavior.
 
+Filesystem-based template loaders catch more specific exceptions
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+When using the :class:`filesystem.Loader <django.template.loaders.filesystem.Loader>`
+or :class:`app_directories.Loader <django.template.loaders.app_directories.Loader>`
+template loaders, earlier versions of Django raised a
+:exc:`~django.template.TemplateDoesNotExist` error if a template source existed
+but was unreadable. This could happen under many circumstances, such as if
+Django didn't have permissions to open the file, or if the template source was
+a directory. Now, Django only silences the exception if the template source
+does not exist. All other situations result in the original ``IOError`` being
+raised.
+
 Miscellaneous
 ~~~~~~~~~~~~~
 

tests/template_tests/test_loaders.py

@@ -3,6 +3,7 @@
 
 import os.path
 import sys
+import tempfile
 import types
 import unittest
 from contextlib import contextmanager
@@ -176,7 +177,16 @@ def test_not_installed(self):
 class FileSystemLoaderTests(SimpleTestCase):
 
     def setUp(self):
-        self.engine = Engine()
+        self.engine = Engine(dirs=[TEMPLATE_DIR])
+
+    @contextmanager
+    def set_dirs(self, dirs):
+        original_dirs = self.engine.dirs
+        self.engine.dirs = dirs
+        try:
+            yield
+        finally:
+            self.engine.dirs = original_dirs
 
     @contextmanager
     def source_checker(self, dirs):
@@ -189,12 +199,8 @@ def check_sources(path, expected_sources):
                 expected_sources,
             )
 
-        original_dirs = self.engine.dirs
-        self.engine.dirs = dirs
-        try:
+        with self.set_dirs(dirs):
             yield check_sources
-        finally:
-            self.engine.dirs = original_dirs
 
     def test_directory_security(self):
         with self.source_checker(['/dir1', '/dir2']) as check_sources:
@@ -238,6 +244,27 @@ def test_case_sensitivity(self):
             check_sources('index.html', ['/dir1/index.html', '/DIR2/index.html'])
             check_sources('/DIR1/index.HTML', ['/DIR1/index.HTML'])
 
+    def test_file_does_not_exist(self):
+        with self.assertRaises(TemplateDoesNotExist):
+            self.engine.get_template('doesnotexist.html')
+
+    @unittest.skipIf(
+        sys.platform == 'win32',
+        "Python on Windows doesn't have working os.chmod().",
+    )
+    def test_permissions_error(self):
+        with tempfile.NamedTemporaryFile() as tmpfile:
+            tmpdir = os.path.dirname(tmpfile.name)
+            tmppath = os.path.join(tmpdir, tmpfile.name)
+            os.chmod(tmppath, 0o0222)
+            with self.set_dirs([tmpdir]):
+                with self.assertRaisesMessage(IOError, 'Permission denied'):
+                    self.engine.get_template(tmpfile.name)
+
+    def test_notafile_error(self):
+        with self.assertRaisesMessage(IOError, 'Is a directory'):
+            self.engine.get_template('first')
+
 
 class AppDirectoriesLoaderTest(SimpleTestCase):
 

tests/view_tests/tests/test_debug.py

@@ -7,7 +7,6 @@
 import inspect
 import os
 import re
-import shutil
 import sys
 import tempfile
 from unittest import skipIf
@@ -152,36 +151,6 @@ def test_template_loader_postmortem(self):
                 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 tempfile.NamedTemporaryFile() as tmpfile:
-            template_name = tmpfile.name
-            tempdir = os.path.dirname(tmpfile.name)
-            template_path = os.path.join(tempdir, template_name)
-            os.chmod(template_path, 0o0222)
-            with override_settings(TEMPLATES=[{
-                'BACKEND': 'django.template.backends.django.DjangoTemplates',
-                '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 = tempfile.mkdtemp()
-            template_name = os.path.basename(template_path)
-            tempdir = os.path.dirname(template_path)
-            with override_settings(TEMPLATES=[{
-                'BACKEND': 'django.template.backends.django.DjangoTemplates',
-                '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)
-
     def test_no_template_source_loaders(self):
         """
         Make sure if you don't specify a template, the debug view doesn't blow up.