Skip to content

gh-151221: Fix plistlib loading of partial ISO 8601 dates #151217

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
JavaZeroo wants to merge 3 commits into from
+30 −6
Closed

gh-151221: Fix plistlib loading of partial ISO 8601 dates #151217

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
d549737
Fix plistlib loading of partial ISO 8601 dates
JavaZeroo Jun 10, 2026
526bbb5
Add NEWS entry
JavaZeroo Jun 10, 2026
c0c74b2
Document the behaviour change in plistlib docs
JavaZeroo Jun 10, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 5 additions & 0 deletions Doc/library/plistlib.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,11 @@ This module defines the following functions:
.. versionchanged:: 3.13
The keyword-only parameter *aware_datetime* has been added.

.. versionchanged:: next
``<date>`` values that omit smaller units (for example ``2024-06Z``)
are now accepted, with the omitted components defaulting to the start
of the period. Previously such values raised :exc:`TypeError`.


.. function:: loads(data, *, fmt=None, dict_type=dict, aware_datetime=False)

Expand Down
10 changes: 4 additions & 6 deletions Lib/plistlib.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -139,13 +139,11 @@ def _decode_base64(s):

def _date_from_string(s, aware_datetime):
order = ('year', 'month', 'day', 'hour', 'minute', 'second')
# Smaller units may be omitted; default them to the start of the period.
defaults = (1, 1, 1, 0, 0, 0)
gd = _dateParser.match(s).groupdict()
lst = []
for key in order:
val = gd[key]
if val is None:
break
lst.append(int(val))
lst = [int(val) if (val := gd[key]) is not None else default
for key, default in zip(order, defaults)]
if aware_datetime:
return datetime.datetime(*lst, tzinfo=datetime.UTC)
return datetime.datetime(*lst)
Expand Down
18 changes: 18 additions & 0 deletions Lib/test/test_plistlib.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -938,6 +938,24 @@ def test_load_aware_datetime(self):
aware_datetime=True)
self.assertEqual(dt.tzinfo, datetime.UTC)

def test_load_partial_datetime(self):
# Smaller units may be omitted; missing components default to the
# start of the period.
for data, expected in [
(b"<plist><date>2024Z</date></plist>",

@AleksaMCode AleksaMCode Jun 10, 2026

Copy link
Copy Markdown

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm not sure if 2024Z is a valid ISO 8601 format. While year only (YYYY) format is ISO, I think timezone designators (in this case Zulu time) can only be attached to complete time value, not a standalone year.

@JavaZeroo JavaZeroo Jun 10, 2026

Copy link
Copy Markdown
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

You're right, Z only belongs on a full time value, so 2024Z isn't strictly valid ISO 8601. Whether to accept partial dates at all is still being discussed in the issue. If accepted, I'll drop the Z from the examples.

datetime.datetime(2024, 1, 1)),
(b"<plist><date>2024-06Z</date></plist>",
datetime.datetime(2024, 6, 1)),
(b"<plist><date>2024-06-07Z</date></plist>",
datetime.datetime(2024, 6, 7)),
(b"<plist><date>2024-06-07T08Z</date></plist>",
datetime.datetime(2024, 6, 7, 8)),
(b"<plist><date>2024-06-07T08:09Z</date></plist>",
datetime.datetime(2024, 6, 7, 8, 9)),
]:
with self.subTest(data=data):
self.assertEqual(plistlib.loads(data), expected)

@yuanx749 yuanx749 Jun 16, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Could this test also include one aware_datetime=True case, since this path handles both naive and aware datetimes?

@JavaZeroo JavaZeroo Jul 7, 2026

Copy link
Copy Markdown
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Thankx for reviewing, but picnixz suggested I change the error type to ValueError instead of support it. Therefore, I’ve closed this PR.


@unittest.skipUnless("America/Los_Angeles" in zoneinfo.available_timezones(),
"Can't find timezone datebase")
def test_dump_aware_datetime(self):
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Library/2026-06-10-06-36-35.gh-issue-151221.DPeEZr.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Fix :mod:`plistlib` raising a confusing :exc:`TypeError` when loading a
``<date>`` that omits smaller units (for example ``2024-06Z`` or ``2024Z``).
The omitted components now default to the start of the period.
Loading