Fixed #30324 -- Forced utf-8 encoding when loading the template for the technical 500 debug page.

Regression in 50b8493. Related to ea542a9.

Author: ngnpope

django/views/debug.py

@@ -328,14 +328,14 @@ def get_traceback_data(self):
 
  def get_traceback_html(self):
  """Return HTML version of debug 500 HTTP error page."""
- with Path(CURRENT_DIR, 'templates', 'technical_500.html').open() as fh:
+ with Path(CURRENT_DIR, 'templates', 'technical_500.html').open(encoding='utf-8') as fh:
  t = DEBUG_ENGINE.from_string(fh.read())
  c = Context(self.get_traceback_data(), use_l10n=False)
  return t.render(c)
 
  def get_traceback_text(self):
  """Return plain text version of debug 500 HTTP error page."""
- with Path(CURRENT_DIR, 'templates', 'technical_500.txt').open() as fh:
+ with Path(CURRENT_DIR, 'templates', 'technical_500.txt').open(encoding='utf-8') as fh:
  t = DEBUG_ENGINE.from_string(fh.read())
  c = Context(self.get_traceback_data(), autoescape=False, use_l10n=False)
  return t.render(c)

docs/releases/2.2.1.txt

@@ -14,3 +14,6 @@ Bugfixes
  (:ticket:`30307`).
 
 * Added compatibility for ``psycopg2`` 2.8 (:ticket:`30331`).
+
+* Fixed a regression in Django 2.2 that caused a crash when loading the
+ template for the technical 500 debug page (:ticket:`30324`).

tests/view_tests/tests/test_debug.py

@@ -7,6 +7,7 @@
 import threading
 from io import StringIO
 from pathlib import Path
+from unittest import mock
 
 from django.core import mail
 from django.core.files.uploadedfile import SimpleUploadedFile
@@ -20,7 +21,8 @@
 from django.utils.safestring import mark_safe
 from django.views.debug import (
  CLEANSED_SUBSTITUTE, CallableSettingWrapper, ExceptionReporter,
- cleanse_setting, technical_500_response,
+ Path as DebugPath, cleanse_setting, default_urlconf,
+ technical_404_response, technical_500_response,
 )
 
 from ..views import (
@@ -648,6 +650,20 @@ def __str__(self):
  text = reporter.get_traceback_text()
  self.assertIn('USER: [unable to retrieve the current user]', text)
 
+ def test_template_encoding(self):
+ """
+ The templates are loaded directly, not via a template loader, and
+ should be opened as utf-8 charset as is the default specified on
+ template engines.
+ """
+ reporter = ExceptionReporter(None, None, None, None)
+ with mock.patch.object(DebugPath, 'open') as m:
+ reporter.get_traceback_html()
+ m.assert_called_once_with(encoding='utf-8')
+ m.reset_mock()
+ reporter.get_traceback_text()
+ m.assert_called_once_with(encoding='utf-8')
+
 
 class PlainTextReportTests(SimpleTestCase):
  rf = RequestFactory()