Learnt from: KJhellico
PR: vacanza/holidays#2614
File: holidays/countries/guyana.py:114-116
Timestamp: 2025-06-14T20:36:17.239Z
Learning: In the holidays codebase, message comments should always use en_US spelling conventions, while translatable strings can use appropriate local spellings for the target country/region.

Learnt from: PPsyrius
PR: vacanza/holidays#2537
File: holidays/countries/finland.py:0-0
Timestamp: 2025-05-10T04:32:15.760Z
Learning: In the holidays package, detailed historical context and additional information should be added as comments at the method level or above conditional blocks, while comments directly above tr() function calls should only contain the holiday name itself (e.g., "# Independence Day.").

Learnt from: KJhellico
PR: vacanza/holidays#2684
File: holidays/locale/it/LC_MESSAGES/SM.po:13-13
Timestamp: 2025-06-28T10:39:19.185Z
Learning: In the holidays project, .po file header comments use the format "# [Country] holidays." for default language files (without trailing hash) and "# [Country] holidays [locale] localization." for non-default language files (also without trailing hash).

Learnt from: ankushhKapoor
PR: vacanza/holidays#2601
File: holidays/locale/en_MN/LC_MESSAGES/MN.po:13-14
Timestamp: 2025-06-11T18:32:25.595Z
Learning: For non-default locale `.po` files, the header comment format is:
`# <Country> holidays <locale> localization.` (no trailing hash).

Learnt from: PPsyrius
PR: vacanza/holidays#2638
File: holidays/countries/svalbard_and_jan_mayen.py:1-12
Timestamp: 2025-06-16T11:42:28.293Z
Learning: In the holidays library codebase, country implementation files in holidays/countries/ follow a standard convention of NOT having module-level docstrings. They start with the license header comment block, followed by imports, then class definitions. This is consistent across all country implementations like austria.py, belgium.py, canada.py, etc.

Learnt from: PPsyrius
PR: vacanza/holidays#2843
File: holidays/countries/burundi.py:63-101
Timestamp: 2025-08-21T04:56:03.780Z
Learning: In the holidays library, countries with localization support DO use tr() wrappers around holiday names when calling _add_* methods. This is the correct pattern for l10n-enabled country implementations, contrary to previous learning about translation being handled internally by _add_* methods.

Learnt from: PPsyrius
PR: vacanza/holidays#2642
File: holidays/countries/france.py:178-180
Timestamp: 2025-06-18T10:26:50.180Z
Learning: In the France holidays implementation, the _populate_subdiv_57_public_holidays() (Moselle) and _populate_subdiv_6ae_public_holidays() (Alsace) methods are functionally identical, both adding Good Friday (≥1893) and Saint Stephen's Day (≥1892) with the same legal references from August 16th, 1892. Therefore, for the deprecated "Alsace-Moselle" subdivision, calling either method produces the same result.

Learnt from: PPsyrius
PR: vacanza/holidays#2638
File: holidays/countries/svalbard_and_jan_mayen.py:1-12
Timestamp: 2025-06-16T11:42:28.293Z
Learning: In the holidays library codebase, country implementation files in holidays/countries/ follow a standard convention of NOT having module-level docstrings. They start with the license header comment block, followed by imports, then class definitions. This is consistent across all country implementations like austria.py, belgium.py, canada.py, etc.

Learnt from: PPsyrius
PR: vacanza/holidays#2642
File: holidays/countries/france.py:178-182
Timestamp: 2025-06-18T10:18:59.447Z
Learning: In the France holidays implementation, deprecated subdivision names like "Alsace-Moselle" and "Saint-Barthélémy" are handled through explicit conditionals in _populate_public_holidays() that map them to their corresponding new subdivision-specific holiday population methods, providing backward compatibility while users transition to the new ISO codes.

Learnt from: PPsyrius
PR: vacanza/holidays#2643
File: holidays/countries/mauritius.py:144-169
Timestamp: 2025-06-19T02:34:18.382Z
Learning: Custom holiday classes that extend _CustomHinduHolidays, _CustomIslamicHolidays, _CustomBuddhistHolidays, etc. in the holidays library do not use docstrings. They follow a pattern of using only inline comments above date dictionaries, as seen in Malaysia, Singapore, UAE, and other country implementations.

Learnt from: PPsyrius
PR: vacanza/holidays#2642
File: holidays/countries/french_southern_territories.py:41-44
Timestamp: 2025-06-18T10:07:58.780Z
Learning: Territorial holiday classes that inherit from parent countries (like HolidaysAX from Finland, HolidaysSJ from Norway, HolidaysTF from France) follow a standard pattern of silently overriding self.subdiv in their _populate_public_holidays() method without validation, as this ensures they always use the correct subdivision code for their territory regardless of user input.

Learnt from: PPsyrius
PR: vacanza/holidays#2642
File: holidays/countries/france.py:184-206
Timestamp: 2025-06-18T10:58:28.058Z
Learning: In the holidays library France implementation, creating shared private methods between subdivision-specific holiday population methods (like _populate_subdiv_57_public_holidays and _populate_subdiv_6ae_public_holidays) is not supported by the current framework architecture, so duplicate code between functionally identical subdivision methods should be left as-is.

Learnt from: KJhellico
PR: vacanza/holidays#2386
File: holidays/countries/nepal.py:24-26
Timestamp: 2025-03-30T20:18:46.006Z
Learning: In the holidays library, country classes do not directly implement `_populate()`. Instead, they implement specialized methods like `_populate_public_holidays()`, and the base class `HolidayBase` handles the orchestration by calling these specialized methods.

Learnt from: PPsyrius
PR: vacanza/holidays#2881
File: tests/countries/test_saint_helena_ascension_and_tristan_da_cunha.py:209-209
Timestamp: 2025-09-14T17:17:14.353Z
Learning: In tests/countries/test_saint_helena_ascension_and_tristan_da_cunha.py, the explicit loop iteration pattern for subdivision-specific holiday checks (like Anniversary Day for TA subdivision) is intentionally preferred over using assertSubdivTa helper methods, as confirmed by PPsyrius.

Learnt from: PPsyrius
PR: vacanza/holidays#2638
File: holidays/countries/svalbard_and_jan_mayen.py:26-32
Timestamp: 2025-06-16T11:46:35.303Z
Learning: When creating country holiday aliases that inherit from parent countries (like Svalbard and Jan Mayen from Norway, or Åland from Finland), it's standard practice to hardcode a specific subdivision code in the _populate methods since the subdivision codes for the parent country yield identical results. The Åland Islands implementation serves as the reference pattern for this approach.

Learnt from: KJhellico
PR: vacanza/holidays#2623
File: holidays/countries/christmas_island.py:110-112
Timestamp: 2025-07-09T20:27:37.760Z
Learning: In Christmas Island, ANZAC Day (April 25) follows the same observed holiday rules as other holidays, using the SAT_SUN_TO_NEXT_MON rule to move to Monday when it falls on a weekend. The implementation correctly uses `_add_observed` wrapper around `_add_anzac_day`.

Learnt from: KJhellico
PR: vacanza/holidays#2608
File: tests/countries/test_saint_vincent_and_the_grenadines.py:162-178
Timestamp: 2025-07-02T18:17:53.342Z
Learning: In the Saint Vincent and the Grenadines holidays implementation, New Year's Day is added without observed rules using `_add_new_years_day()` and should not include observed rule testing in its test method. Only holidays explicitly wrapped with `_add_observed()` have observed behavior.

Learnt from: PPsyrius
PR: vacanza/holidays#2609
File: holidays/countries/nauru.py:57-60
Timestamp: 2025-06-14T11:04:31.180Z
Learning: In the holidays library, the base `HolidayBase._populate()` method already includes a guard clause that prevents holiday population methods like `_populate_public_holidays()` from being called when the year is before `start_year` or after `end_year`. Therefore, individual country implementations do not need to add their own guard clauses for years before independence or other start dates.

Learnt from: PPsyrius
PR: vacanza/holidays#2706
File: holidays/countries/cayman_islands.py:80-97
Timestamp: 2025-07-10T03:36:16.461Z
Learning: In the holidays library, date dictionaries that map years to specific dates (like queens_birthday_dates, spring_bank_dates, thanksgiving_day_dates, etc.) are typically defined within the _populate_public_holidays method rather than as module-level constants. This is the established library-wide pattern seen across multiple country implementations including United Kingdom, United States, Sri Lanka, and others.

Learnt from: PPsyrius
PR: vacanza/holidays#2706
File: holidays/countries/cayman_islands.py:80-97
Timestamp: 2025-07-10T03:36:16.461Z
Learning: In the holidays library, date dictionaries that map years to specific dates (like queens_birthday_dates, special holiday dates, etc.) are typically defined within the _populate_public_holidays method rather than as module-level constants. This is the established library-wide pattern and should be maintained for consistency.