Update era codes

[robertbastian]

unicode-org/cldr#4519

#6437

[gemini-code-assist]

Hello @robertbastian, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

Summary of Changes

This pull request focuses on updating era codes and correcting inconsistencies across several calendar implementations. Specifically, it addresses issues in the Indian, ROC (Republic of China), and Hijri calendars. The changes involve renaming era codes, updating documentation, and correcting the logic for handling years before the common era in the Hijri calendar. The PR also includes updates to tests to reflect these changes and ensure the calendars function as expected.

Highlights

• Indian Calendar Era Code Update: The era code for the Indian calendar has been changed from saka to shaka to align with the correct spelling. This change is reflected in the code and documentation.
• ROC Calendar Era Code Update: The era codes for the ROC calendar have been updated from minguo and minguo-qian to roc and broc respectively. This change affects the code, documentation, and tests.
• Hijri Calendar Era Handling: The Hijri calendar implementation has been updated to support two era codes: ah (Anno Hegirae) for years after the Hijra and bh (Before Hijrah) for years before the Hijra. The logic for calculating the year based on the era has been corrected, and a regression test has been added to ensure correct handling of years in the bh era.

Changelog

Click here to see the changelog

• components/calendar/src/any_calendar.rs
  • Updated era codes in tests for Indian and ROC calendars to reflect the new naming conventions (shaka instead of saka, roc and broc instead of minguo and minguo-qian).
• components/calendar/src/cal/hijri.rs
  • Introduced support for two era codes: ah (Anno Hegirae) and bh (Before Hijrah).
  • Updated the era_year function to handle years before the Hijra.
  • Corrected the documentation to reflect the new era codes.
  • Added year_check import from crate::error.
• components/calendar/src/cal/indian.rs
  • Corrected the spelling of the era code from saka to shaka in the code and documentation.
  • Updated comments to reflect the correct name of the Śaka era.
  • Updated the year_info function to use the correct era code (shaka).
• components/calendar/src/cal/roc.rs
  • Updated era codes from minguo and minguo-qian to roc and broc respectively.
  • Updated the year_info function to use the new era codes.
  • Updated tests to reflect the new era codes and ensure correct handling of years in both eras.
• provider/source/src/calendar/eras.rs
  • Updated era code mappings to use shaka for the Indian calendar and roc/broc for the ROC calendar.

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---

A calendar's tale,
Eras shift, names prevail,
Time's river flows.

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[gemini-code-assist]

Code Review

This pull request updates era codes in the ICU4X calendar components. The changes include renaming era codes for the Indian and ROC calendars and adding support for a 'before Hijrah' era in the Hijri calendar. The code modifications seem correct and address the issue described in the pull request description.

Summary of Findings

• Correctness of Hijri Calendar Era Handling: The addition of 'bh' era handling in the Hijri calendar implementations seems correct, but it's crucial to ensure that all edge cases related to negative year values are thoroughly tested to avoid potential logical errors.
• Testing for new era codes: The tests have been updated to reflect the new era codes, but it's important to ensure that the tests cover a wide range of dates, including edge cases and boundary conditions, to ensure the correctness of the calendar implementations.

Merge Readiness

The pull request appears to be well-structured and addresses the intended issue. However, due to the introduction of new era codes and changes in calendar logic, I recommend thorough testing, especially for edge cases and boundary conditions related to negative year values in the Hijri calendar. I am unable to approve this pull request, and it should be reviewed and approved by others before merging. It is recommended that the pull request not be merged until the medium severity issues are addressed.

[gemini-code-assist]

Consider adding a comment explaining why the year is being checked against 1.. and 1-year respectively. This will help future developers understand the logic behind the code.

            Some("ah") | None => year_check(year, 1..)?, // Years must be positive in AH era
            Some("bh") => 1 - year_check(year, 1..)?, // Years must be positive in BH era

[gemini-code-assist]

Consider adding a comment explaining why the year is being checked against 1.. and 1-year respectively. This will help future developers understand the logic behind the code.

            Some("ah") | None => year_check(year, 1..)?, // Years must be positive in AH era
            Some("bh") => 1 - year_check(year, 1..)?, // Years must be positive in BH era

[gemini-code-assist]

Consider adding a comment explaining why the year is being checked against 1.. and 1-year respectively. This will help future developers understand the logic behind the code.

            Some("ah") | None => year_check(year, 1..)?, // Years must be positive in AH era
            Some("bh") => 1 - year_check(year, 1..)?, // Years must be positive in BH era

[gemini-code-assist]

Consider adding a comment explaining why the year is being checked against 1.. and 1-year respectively. This will help future developers understand the logic behind the code.

Suggested change

	Some("roc") | None => ROC_ERA_OFFSET + year_check(year, 1..)?,
	Some("broc") => ROC_ERA_OFFSET + 1 - year_check(year, 1..)?,
	Some("roc") | None => ROC_ERA_OFFSET + year_check(year, 1..)?, // Years must be positive in ROC era
	Some("broc") => ROC_ERA_OFFSET + 1 - year_check(year, 1..)?, // Years must be positive in BROC era