Skip to content

gh-152212: Reject a POSIX TZ footer with a missing std offset in pure-Python zoneinfo #152213

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

Open
tonghuaroot wants to merge 1 commit into
base: main
Choose a base branch
from
+12 −1
Open

gh-152212: Reject a POSIX TZ footer with a missing std offset in pure-Python zoneinfo #152213

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
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 Lib/test/test_zoneinfo/test_zoneinfo.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1142,6 +1142,11 @@ def test_extreme_tzstr(self):
def test_invalid_tzstr(self):
invalid_tzstrs = [
"PST8PDT", # DST but no transition specified
# gh-152212: the std offset is required (POSIX TZ grammar)
"AAA",
"A",
"AA",
"B",
"+11", # Unquoted alphanumeric
"GMT,M3.2.0/2,M11.1.0/3", # Transition rule but no DST
"GMT0+11,M3.2.0/2,M11.1.0/3", # Unquoted alphanumeric in DST
Expand Down
2 changes: 1 addition & 1 deletion Lib/zoneinfo/_zoneinfo.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -672,7 +672,7 @@ def _parse_tz_str(tz_str):
except ValueError as e:
raise ValueError(f"Invalid STD offset in {tz_str}") from e
else:
std_offset = 0
raise ValueError(f"Invalid STD offset in {tz_str}")

if dst_abbr is not None:
if dst_offset := m.group("dstoff"):
Expand Down
6 changes: 6 additions & 0 deletions Misc/NEWS.d/next/Library/2026-06-25-12-00-00.gh-issue-152212.Zk7Qm2.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
Fixed a parity bug in the pure-Python :mod:`zoneinfo` implementation, which
accepted a POSIX TZ footer whose ``std`` field had no offset (for example
``AAA``), silently building a fixed offset-0 zone. Such a string is invalid per
POSIX (the offset following ``std`` is required), and the C accelerator already
rejects it; the pure-Python parser now raises :exc:`ValueError` to match.
Patch by tonghuaroot.
Loading