No Content-Type text/html on empty exception views [4.x] (#1088)

* Only set response header Content-Type as text/html on exception views when the response has content. This fixes a problem in Plone with caching.
* Fix test and add new test for Content-Type header of empty exception body.
* Apply code review changes co-authored-by: Jens Vagelpohl <jens@plyp.com>
* Fix tox lint. Use isort 5, which isort-apply was already using.
* tox -e isort-apply
* Please both flake8 and isort for an unused BBB import.
* Fix tox -e docs, Locally I got Python 3.10, which cannot install this version of Zope.

CHANGES.rst

@@ -10,6 +10,10 @@ https://zope.readthedocs.io/en/2.13/CHANGES.html
 4.8.7 (unreleased)
 ------------------
 
+- Only set response header Content-Type as text/html on exception views when
+  the response has content.
+  (`#1089 <https://github.com/zopefoundation/Zope/issues/1089>`_)
+
 - Update dependencies to the latest releases for each supported Python version.
 
 

src/App/tests/test_ApplicationManager.py

@@ -464,6 +464,7 @@ def _makeOne(self, id):
     def _makeModuleClasses(self):
         import sys
         import types
+
         from ExtensionClass import Base
 
         class Foo(Base):
@@ -513,6 +514,7 @@ def test_refdict(self):
 
     def test_rcsnapshot(self):
         import sys
+
         import App.ApplicationManager
         from DateTime.DateTime import DateTime
         dm = self._makeOne('test')

src/App/tests/test_getZopeVersion.py

@@ -15,9 +15,8 @@
 
 import unittest
 
-from pkg_resources import get_distribution
-
 from App.version_txt import getZopeVersion
+from pkg_resources import get_distribution
 
 
 class Test(unittest.TestCase):

src/OFS/Application.py

@@ -295,8 +295,8 @@ def install_inituser(self):
     def install_virtual_hosting(self):
         app = self.getApp()
         if 'virtual_hosting' not in app:
-            from Products.SiteAccess.VirtualHostMonster \
-                import VirtualHostMonster
+            from Products.SiteAccess.VirtualHostMonster import \
+                VirtualHostMonster
             any_vhm = [obj for obj in app.values()
                        if isinstance(obj, VirtualHostMonster)]
             if not any_vhm:
@@ -308,8 +308,8 @@ def install_virtual_hosting(self):
     def install_root_view(self):
         app = self.getApp()
         if 'index_html' not in app:
-            from Products.PageTemplates.ZopePageTemplate \
-                import ZopePageTemplate
+            from Products.PageTemplates.ZopePageTemplate import \
+                ZopePageTemplate
             root_pt = ZopePageTemplate('index_html')
             root_pt.pt_setTitle(u'Auto-generated default page')
             app._setObject('index_html', root_pt)

src/OFS/ObjectManager.py

@@ -799,6 +799,7 @@ def manage_FTPstat(self, REQUEST):
                  u'Zope 5.', DeprecationWarning, stacklevel=2)
             mode = 0o0040000
             from AccessControl.User import nobody
+
             # check to see if we are acquiring our objectValues or not
             parents = REQUEST.PARENTS
             if not (len(parents) > 1

src/OFS/bbb.py

@@ -12,7 +12,6 @@
 ##############################################################################
 
 import pkg_resources
-
 from zope.deferredimport import deprecated
 
 

src/OFS/tests/applicationproduct/__init__.py

@@ -5,8 +5,8 @@
 
 
 def initialize(context):
-    from OFS.Folder import Folder
     import transaction
+    from OFS.Folder import Folder
 
     app = context.getApplication()
     folder = Folder('some_folder')

src/OFS/tests/testApplication.py

@@ -93,8 +93,9 @@ def test_bobo_traverse_attribute_key_miss_R_M_is_GET(self):
         self.assertRaises(KeyError, app.__bobo_traverse__, request, 'NONESUCH')
 
     def test_bobo_traverse_attribute_key_miss_R_M_not_GET_POST(self):
+        from Acquisition import aq_inner
+        from Acquisition import aq_parent
         from webdav.NullResource import NullResource
-        from Acquisition import aq_inner, aq_parent
 
         app = self._makeOne()
         app._getOb = _noWay

src/OFS/tests/testCopySupport.py

@@ -362,8 +362,9 @@ def _scrubSecurity(self):
     def _assertCopyErrorUnauth(self, callable, *args, **kw):
 
         import re
-        from zExceptions import Unauthorized
+
         from OFS.CopySupport import CopyError
+        from zExceptions import Unauthorized
 
         ce_regex = kw.get('ce_regex')
         if ce_regex is not None:

src/OFS/tests/testEtagSupport.py

@@ -4,8 +4,8 @@
 class TestEtagSupport(unittest.TestCase):
 
     def test_interfaces(self):
-        from zope.interface.verify import verifyClass
         from OFS.EtagSupport import EtagBaseInterface
         from OFS.EtagSupport import EtagSupport
+        from zope.interface.verify import verifyClass
 
         verifyClass(EtagBaseInterface, EtagSupport)

src/OFS/tests/testFileAndImage.py

@@ -314,9 +314,9 @@ def test_manage_DAVget_text(self):
         self.assertEqual(self.file.manage_DAVget(), text)
 
     def test_interfaces(self):
-        from zope.interface.verify import verifyClass
         from OFS.Image import File
         from OFS.interfaces import IWriteLock
+        from zope.interface.verify import verifyClass
         from ZPublisher.HTTPRangeSupport import HTTPRangeInterface
 
         verifyClass(HTTPRangeInterface, File)
@@ -370,9 +370,9 @@ def testViewImageOrFile(self):
         self.assertEqual(result, self.data)
 
     def test_interfaces(self):
-        from zope.interface.verify import verifyClass
         from OFS.Image import Image
         from OFS.interfaces import IWriteLock
+        from zope.interface.verify import verifyClass
 
         verifyClass(IWriteLock, Image)
 

src/OFS/tests/testObjectManager.py

@@ -608,9 +608,9 @@ def test_export_import(self):
 
         from OFS.Folder import Folder
         from OFS.Image import File
-        from ZODB.DemoStorage import DemoStorage
-        from ZODB.DB import DB
         from transaction import commit
+        from ZODB.DB import DB
+        from ZODB.DemoStorage import DemoStorage
         try:
             tf = None  # temporary file required for export/import
             # export/import needs the object manager in ZODB

src/OFS/tests/testRanges.py

@@ -49,6 +49,7 @@ class TestRequestRange(unittest.TestCase):
     def setUp(self):
         import io
         import string
+
         import transaction
         from OFS.Application import Application
         from OFS.Folder import manage_addFolder
@@ -168,9 +169,9 @@ def expectSingleRange(self, range, start, end, if_range=None):
         self.assertEqual(body, self.data[start:end])
 
     def expectMultipleRanges(self, range, sets, draft=0):
+        import email
         import io
         import re
-        import email
         rangeParse = re.compile(r'bytes\s*(\d+)-(\d+)/(\d+)')
         req = self.app.REQUEST
         rsp = req.RESPONSE

src/OFS/tests/testTraverse.py

@@ -45,8 +45,8 @@ class ProtectedMethodSecurityPolicy(object):
     """Check security strictly on bound methods.
     """
     def validate(self, accessed, container, name, value, *args):
-        from Acquisition import aq_base
         from AccessControl import Unauthorized
+        from Acquisition import aq_base
         if getattr(aq_base(value), '__self__', None) is None:
             return 1
 
@@ -65,6 +65,7 @@ class TestTraverse(unittest.TestCase):
 
     def setUp(self):
         import io
+
         import transaction
         from AccessControl import SecurityManager
         from AccessControl.SecurityManagement import newSecurityManager
@@ -393,9 +394,10 @@ def testDefaultValueWhenUnathorized(self):
             self.root.folder1.restrictedTraverse('stuff', 42), 42)
 
     def testNotFoundIsRaised(self):
+        from operator import getitem
+
         from OFS.SimpleItem import SimpleItem
         from zExceptions import NotFound
-        from operator import getitem
         self.folder1._setObject('foo', SimpleItem('foo'))
         self.assertRaises(AttributeError, getitem, self.folder1.foo,
                           'doesntexist')

src/OFS/tests/test_DTMLDocument.py

@@ -15,8 +15,8 @@ def _makeOne(self, *args, **kw):
         return self._getTargetClass()(*args, **kw)
 
     def test_class_conforms_to_IWriteLock(self):
-        from zope.interface.verify import verifyClass
         from OFS.interfaces import IWriteLock
+        from zope.interface.verify import verifyClass
         verifyClass(IWriteLock, self._getTargetClass())
 
     def test_manage_upload__bytes(self):
@@ -70,8 +70,8 @@ class FactoryTests(unittest.TestCase):
 
     def test_defaults_no_standard_html_header(self):
         # see LP #496961
-        from OFS.DTMLDocument import addDTMLDocument
         from OFS.DTMLDocument import DTMLDocument
+        from OFS.DTMLDocument import addDTMLDocument
         dispatcher = DummyDispatcher()
         addDTMLDocument(dispatcher, 'id')
         method = dispatcher._set['id']

src/OFS/tests/test_DTMLMethod.py

@@ -15,8 +15,8 @@
 
 
 def _lock_item(item):
-    from OFS.LockItem import LockItem
     from AccessControl.users import nobody
+    from OFS.LockItem import LockItem
     item.wl_setLock('token', LockItem(nobody, token='token'))
 
 
@@ -30,8 +30,8 @@ def _makeOne(self, *args, **kw):
         return self._getTargetClass()(*args, **kw)
 
     def test_class_conforms_to_IWriteLock(self):
-        from zope.interface.verify import verifyClass
         from OFS.interfaces import IWriteLock
+        from zope.interface.verify import verifyClass
         verifyClass(IWriteLock, self._getTargetClass())
 
     def test_edit_taintedstring(self):
@@ -264,8 +264,8 @@ class FactoryTests(unittest.TestCase):
 
     def test_defaults_no_standard_html_header(self):
         # see LP #496961
-        from OFS.DTMLMethod import addDTMLMethod
         from OFS.DTMLMethod import DTMLMethod
+        from OFS.DTMLMethod import addDTMLMethod
         dispatcher = DummyDispatcher()
         addDTMLMethod(dispatcher, 'id')
         method = dispatcher._set['id']

src/OFS/tests/test_Uninstalled.py

@@ -112,10 +112,10 @@ def test_Broken_instance___getattr___allows_persistence_attrs(self):
 class TestsIntegratedBroken(base.TestCase):
 
     def test_Broken_instance___getstate___gives_access_to_its_state(self):
+        import transaction
         from Acquisition import aq_base
-        from OFS.Uninstalled import BrokenClass
         from OFS.tests import test_Uninstalled
-        import transaction
+        from OFS.Uninstalled import BrokenClass
 
         # store an instance
         tr = ToBreak()

src/OFS/tests/test_metaconfigure.py

@@ -21,8 +21,9 @@ def setUp(self):
         OFS.metaconfigure._meta_type_regs[:] = []
 
     def tearDown(self):
-        from zope.component.testing import tearDown
         import OFS.metaconfigure
+        from zope.component.testing import tearDown
+
         # restore registrations
         OFS.metaconfigure._meta_type_regs[:] = self._old_mt_regs
         OFS.metaconfigure._register_monkies[:] = self._old_monkies

src/OFS/userfolder.py

@@ -18,7 +18,7 @@
 from AccessControl import ClassSecurityInfo
 from AccessControl import userfolder as accesscontrol_userfolder
 from AccessControl.class_init import InitializeClass
-from AccessControl.Permissions import manage_users as ManageUsers  # NOQA
+from AccessControl.Permissions import manage_users as ManageUsers
 from AccessControl.requestmethod import requestmethod
 from AccessControl.rolemanager import DEFAULTMAXLISTUSERS
 from AccessControl.users import _remote_user_mode

src/Products/Five/browser/adding.py

@@ -36,7 +36,7 @@
 from zope.component.interfaces import IFactory
 from zope.container.constraints import checkFactory
 from zope.container.constraints import checkObject
-from zope.container.i18n import ZopeMessageFactory as _  # NOQA
+from zope.container.i18n import ZopeMessageFactory as _
 from zope.container.interfaces import IContainerNamesContainer
 from zope.container.interfaces import INameChooser
 from zope.event import notify

src/Products/Five/browser/tests/test_i18n.py

@@ -83,7 +83,8 @@ def test_zpt_i18n():
 
 
 def test_suite():
-    from Testing.ZopeTestCase import FunctionalDocTestSuite
     import doctest
+
+    from Testing.ZopeTestCase import FunctionalDocTestSuite
     return FunctionalDocTestSuite(
         optionflags=doctest.ELLIPSIS | doctest.NORMALIZE_WHITESPACE)

src/Products/Five/browser/tests/test_pagetemplatefile.py

@@ -35,14 +35,14 @@ def test_getId_with_path(self):
         self.assertEqual(vptf.id, 'dirpage1.pt')
 
     def test_pt_getEngine(self):
+        from Products.PageTemplates.Expressions import SecureModuleImporter
+        from Products.PageTemplates.Expressions import TrustedZopePathExpr
+        from Products.PageTemplates.Expressions import UnicodeAwareStringExpr
+        from zope.contentprovider.tales import TALESProviderExpression
         from zope.tales.expressions import DeferExpr
         from zope.tales.expressions import LazyExpr
         from zope.tales.expressions import NotExpr
         from zope.tales.pythonexpr import PythonExpr
-        from zope.contentprovider.tales import TALESProviderExpression
-        from Products.PageTemplates.Expressions import TrustedZopePathExpr
-        from Products.PageTemplates.Expressions import SecureModuleImporter
-        from Products.PageTemplates.Expressions import UnicodeAwareStringExpr
 
         vptf = self._makeOne('seagull.pt')
         engine = vptf.pt_getEngine()
@@ -59,9 +59,9 @@ def test_pt_getEngine(self):
         self.assertEqual(engine.base_names['modules'], SecureModuleImporter)
 
     def test_pt_getContext_no_kw_no_physicalRoot(self):
+        from AccessControl.SecurityManagement import newSecurityManager
         from Products.Five.browser.pagetemplatefile import ViewMapper
         from Products.PageTemplates.Expressions import SecureModuleImporter
-        from AccessControl.SecurityManagement import newSecurityManager
         newSecurityManager(None, DummyUser('a_user'))
         context = DummyContext()
         request = DummyRequest()
@@ -191,8 +191,8 @@ def test___getitem___miss(self):
         self.assertRaises(ComponentLookupError, mapper.__getitem__, 'nonesuch')
 
     def test___getitem___hit(self):
-        from zope.interface import Interface
         from zope.component import provideAdapter
+        from zope.interface import Interface
 
         def _adapt(context, request):
             return self

src/Products/Five/browser/tests/test_zope3security.py

@@ -152,6 +152,7 @@ def test_allowed_interface():
 
 
 def test_suite():
-    from Testing.ZopeTestCase import FunctionalDocTestSuite
     from doctest import ELLIPSIS
+
+    from Testing.ZopeTestCase import FunctionalDocTestSuite
     return FunctionalDocTestSuite(optionflags=ELLIPSIS)