[Python-checkins] cpython (3.4): #21991: make headerregistry params property MappingProxyType.

[r.david.murray]

https://hg.python.org/cpython/rev/fea3ddcaf652
changeset: 93118:fea3ddcaf652
branch: 3.4
parent: 93115:9ec84f9b61c6
user: R David Murray <rdmurray at bitdance.com>
date: Fri Oct 17 19:30:13 2014 -0400
summary:
#21991: make headerregistry params property MappingProxyType.

It is unlikely anyone is using the fact that the dictionary returned
by the 'params' attribute was previously writable, but even if someone
is the API is provisional so this kind of change is acceptable (and
needed, to get the API "right" before it becomes official).

Patch by St?phane Wirtel.

files:
Lib/email/headerregistry.py | 3 ++-
Lib/test/test_email/test_headerregistry.py | 3 +++
Misc/NEWS | 4 ++++
3 files changed, 9 insertions(+), 1 deletions(-)


diff --git a/Lib/email/headerregistry.py b/Lib/email/headerregistry.py
--- a/Lib/email/headerregistry.py
+++ b/Lib/email/headerregistry.py
@@ -7,6 +7,7 @@
and will probably change some before that happens.

"""
+from types import MappingProxyType

from email import utils
from email import errors
@@ -454,7 +455,7 @@

@property
def params(self):
- return self._params.copy()
+ return MappingProxyType(self._params)


class ContentTypeHeader(ParameterizedMIMEHeader):
diff --git a/Lib/test/test_email/test_headerregistry.py b/Lib/test/test_email/test_headerregistry.py
--- a/Lib/test/test_email/test_headerregistry.py
+++ b/Lib/test/test_email/test_headerregistry.py
@@ -1,6 +1,7 @@
import datetime
import textwrap
import unittest
+import types
from email import errors
from email import policy
from email.message import Message
@@ -235,6 +236,8 @@
self.assertEqual(h.maintype, maintype)
self.assertEqual(h.subtype, subtype)
self.assertEqual(h.params, parmdict)
+ with self.assertRaises(TypeError):
+ h.params['abc'] = 'xyz' # params is read-only.
self.assertDefectsEqual(h.defects, defects)
self.assertEqual(h, decoded)
self.assertEqual(h.fold(policy=policy.default), folded)
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -33,6 +33,10 @@
Library
-------

+- Issue #21991: Make email.headerregistry's header 'params' attributes
+ be read-only (MappingProxyType). Previously the dictionary was modifiable
+ but a new one was created on each access of the attribute.
+
- Issue #22641: In asyncio, the default SSL context for client connections
is now created using ssl.create_default_context(), for stronger security.