[tlq5l]

Pull Request Check List

• Added tests for changed code.
• Updated documentation for changed code. (No docs change needed: the docs never said names were case-sensitive.)

Previously, from_format matched the locale's month and weekday names case-sensitively, so 14nov22 with DDMMMYY raised String does not match format and Turkish MAYIS for Mayıs raised the same error. Cumartesi with dddd in tr parsed as Friday (Cuma), because the parse read the first alternative that matched, not the full match.

This wraps the name tokens (MMMM, MMM, dddd, ddd, dd) in a scoped (?i:...) group in Formatter._replace_tokens and escapes each locale name, so the . in lun. is literal. Locale.match_translation looks a value up by exact match first, then by an escaped re.IGNORECASE full match, the same rule the regex uses, so MAYIS finds May. from_format checks for a full match before it reads the groups, so Cumartesi is Saturday. Other tokens (T, Z, A) keep their case rules. match_translation is only called from from_format parsing.

Callers checked: src/pendulum/__init__.py (from_format is the only caller of Formatter.parse, and the full test suite passes); rust/src/parsing.rs, rust/src/python/parsing.rs, src/pendulum/parser.py and src/pendulum/parsing/__init__.py have their own parsers and do not call it.

Fixes #668.

Ran live on 05c1368: pendulum.from_format('15 MAYIS 2024','DD MMMM YYYY', locale='tr') -> 2024-05-15 00:00:00+00:00 (ValueError before); pendulum.from_format('LUNX','ddd', locale='fr') -> ValueError; pendulum.from_format('14nov22','DDMMMYY') -> 2022-11-14 00:00:00+00:00 (ValueError before).

[Muguett-DBY]

I tried two uppercase Turkish month names and both silently parse as January:

pendulum.from_format("15 MAYIS 2024", "DD MMMM YYYY", locale="tr")
# 2024-01-15 (expected 2024-05-15)

pendulum.from_format("15 NİSAN 2024", "DD MMMM YYYY", locale="tr")
# 2024-01-15 (expected 2024-04-15)

The case-insensitive regex accepts these names, but match_translation() compares the results of .lower(), which differ for Turkish dotted and dotless I. The lookup returns None; _get_parsed_locale_value() then checks value rather than the lookup result, so the missing month defaults to January. On the base branch both inputs raise a format mismatch.

Could we add a Turkish uppercase test and make sure an unmatched translation cannot silently become January?

[tlq5l]

Thanks for the repro. The new head is 05c1368.

Name matching now uses the same case-insensitive rule as the regex, so MAYIS and NİSAN map to May and April. Locale names are now escaped in the regex, and Cumartesi no longer parses as Cuma. A name the lookup cannot map raises ValueError. A new test covers every shipped locale's names in exact, upper and lower case.

AI disclosure: written and checked with Claude Code (tests and live run agent-run); I take responsibility for it.