Reject non-ASCII digits in vWeekday ordwk (BYDAY/BYWEEKDAY/WKST)

[Labib-Bin-Salam]

Linked issue

No related issue; reporting directly (same as #1465).

Description

vWeekday silently accepts non-ASCII digits in the ordwk (relative) part of a BYDAY / BYWEEKDAY / WKST value.

Repro: vWeekday("١٢MO") (Arabic-Indic "12"), or parse a calendar containing RRULE:FREQ=MONTHLY;BYDAY=١٢MO.

>>> from icalendar import vWeekday
>>> w = vWeekday("١٢MO")   # Arabic-Indic digits
>>> w.relative
12

Cause: WEEKDAY_RULE matches the relative part with (?P<relative>[\d]{0,2}). In Python's default Unicode mode, \d is True for non-ASCII decimal digits (Arabic-Indic ١٢, extended-Arabic ۱۲, Devanagari, …). int() then parses those, so a malformed ordwk is silently accepted and normalized to a valid relative number. RFC 5545 §3.3.10 allows only ASCII DIGIT here (ordwk = 1*2DIGIT).

Fix: match [0-9] instead of \d so the grammar agrees with what int() accepts. After the fix, vWeekday("١٢MO") raises ValueError like any other malformed weekday, while every valid ASCII value (MO, 2MO, -1SU, +3WE, 53SU) is unchanged.

This is the direct sibling of the recently merged vMonth fix (#1465), which fixed the same non-ASCII-digit class in BYMONTH.

Checklist

• I've added a change log entry to /news, following the instructions in Change log entry format.
• I've added or updated tests if applicable.
• I've run and ensured all tests pass locally by following Run tests.
• I've added or edited documentation, both as docstrings to be rendered in the API documentation and narrative documentation, as necessary. (N/A — behaviour fix; added an explanatory code comment only.)

Additional information

• Added regression test test_non_ascii_ordwk_digits_rejected (Arabic-Indic and extended-Arabic digits, single- and double-digit) next to the existing vWeekday tests; it fails before the change and passes after.
• ruff check and ruff format --check are clean on the changed files; the targeted prop/ (887) and recurrence/RRULE (444) suites pass locally. (The unrelated test_timezone_identification / test_with_doctest failures reproduce identically on a clean checkout in this environment and are not affected by this change.)
• AI usage disclosure (per the "Responsible AI use" policy): this change was drafted with the assistance of Claude Opus 4.8 (claude-opus-4-8), run via Claude Code — used to locate this sibling of the vMonth fix and to draft the regex change, the regression test, and the change log entry. All output was reviewed, executed, and verified by me, and I take responsibility for it. The model/version and usage are also recorded in the commit message and the disclosure is included in the change log entry.

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📚 Documentation preview 📚: https://icalendar--1488.org.readthedocs.build/en/1488/

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        name: Labib Bin Salam
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          🚀 IT Consultant @TRL | Specializing in, Cloud-Native Infrastructure & Asset, Safety-Critical Data Systems.
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[read-the-docs-community]

Documentation build overview

📚 icalendar | 🛠️ Build #33235058 | 📁 Comparing de6a714 against latest (16fe2ab)

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4 files changed

± 404.html
± contribute/index.html
± _modules/icalendar/parser/string.html
± _modules/icalendar/prop/recur/weekday.html

[angatha]

"12MO" is the valid version, did you mean "١٢MO"?