Enhance TZDB compiler to better match spec

[jodastephen]

• File format is defined by zic manual page
• Add support for more edge cases
• Fixes Broken build after 2024b tz database version #785

Summary by CodeRabbit

• New Features

  • Introduced version 2.13.0, enhancing the parser's functionality for time zone specifications.
  • Improved handling of time zone rules, months, and days of the week for better parsing accuracy.

• Bug Fixes

  • Resolved issue number 785, improving parser alignment with zic specifications.

• Tests

  • Added new test method to validate time zone name formatting, enhancing test coverage.

[coderabbitai]

Walkthrough

Walkthrough

The changes introduced in this pull request encompass the addition of a new release entry for version 2.13.0, which includes a fix to enhance the parser's functionality in ZoneInfoCompiler.java. This fix addresses issue number 785, related to build failures after the 2024b tz database update. The code improvements involve restructuring time zone rule handling, refining parsing logic, and expanding test coverage in TestCompiler.java.

Changes

Files	Change Summary
src/changes/changes.xml	Added release entry for version 2.13.0 and a fix by developer jodastephen addressing issue 785.
src/main/java/org/joda/time/tz/ZoneInfoCompiler.java	Introduced structured sets and maps for time zone rules; updated parsing methods and logic; added helper methods and improved error handling and code readability.
src/test/java/org/joda/time/tz/TestCompiler.java	Modified test cases for time zone rules and added a new test method test_formatName to enhance test coverage.

Assessment against linked issues

Objective	Addressed	Explanation
Fix build failures after 2024b tz database version (#785)	✅
Resolve time zone errors in ZoneInfoCompiler.java (#785)	✅
Improve parsing of time zone rules (#785)	✅

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Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL

Commits

Files that changed from the base of the PR and between 038646b and c633e21.

Files selected for processing (3)

• src/changes/changes.xml (1 hunks)
• src/main/java/org/joda/time/tz/ZoneInfoCompiler.java (13 hunks)
• src/test/java/org/joda/time/tz/TestCompiler.java (3 hunks)

Additional comments not posted (15)

src/test/java/org/joda/time/tz/TestCompiler.java (2)

219-232: LGTM!

The new test method test_formatName provides comprehensive coverage for the formatName method in the ZoneInfoCompiler.Rule class. The test cases cover various scenarios with different inputs, including time zone abbreviations, offsets, and formatting patterns. The expected outputs are correctly defined for each test case, ensuring the formatting logic is thoroughly validated.

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48-70: Looks good!

The updates to the time zone rules for "America/Los_Angeles" and "Canada" in the AMERICA_LOS_ANGELES_FILE test data introduce variations in the abbreviations and formatting. These changes help test the robustness of the parsing logic by using different abbreviations like "r", "RUL", and modifying the month abbreviations and other parameters.

The variations in the test data ensure that the parsing logic can handle different formats and abbreviations correctly. Since the changes are limited to the test data and do not introduce any functional changes to the code being tested, they are safe to include.

src/changes/changes.xml (1)

11-16: LGTM!

The release entry is well-structured and includes all the necessary information. The fix description clearly summarises the changes and referencing the linked issue helps provide additional context.

src/main/java/org/joda/time/tz/ZoneInfoCompiler.java (12)

29-35: LGTM!

The new imports are necessary for the lookup structures introduced later in the class.

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66-82: Great improvement to parsing efficiency and readability!

The introduction of the static lookup sets for parsing time zone data is a significant enhancement. It replaces string comparisons with efficient set lookups, making the parsing logic more readable and performant.

The lookup sets are populated using the expand helper method, which ensures that all valid abbreviations for each name are included, in accordance with the TZDB specification.

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81-105: Excellent addition of lookup maps for months and days of the week!

The introduction of the static lookup maps for parsing months and days of the week is another great improvement. Similar to the lookup sets, these maps replace string comparisons with efficient map lookups, enhancing the parsing logic's readability and performance.

The lookup maps are populated using the put helper method, which ensures that all valid abbreviations for each name are included, in line with the TZDB specification.

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107-122: Helper methods improve code readability and maintainability!

The addition of the put and expand helper methods is a great way to improve code readability and maintainability. These methods encapsulate the logic for populating the lookup structures, making the code more modular and easier to understand.

Moreover, the methods ensure that the lookup structures adhere to the TZDB specification for abbreviating names, maintaining consistency throughout the parsing process.

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259-275: Parsing methods updated to leverage lookup structures and improve error handling!

The updates to the parseYear, parseMonth, and parseDayOfWeek methods significantly improve the parsing logic. By utilizing the new lookup structures, the code becomes more efficient and readable, replacing string comparisons with simple lookups.

Additionally, converting the input to lowercase before performing the lookup ensures case-insensitive parsing, which is a requirement of the TZDB specification.

The improved error handling, with more informative exception messages, enhances the robustness of the parsing process and makes it easier to diagnose and fix issues.

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291-295: Comments and special case handling improve code clarity and compliance!

The addition of comments clarifying the handling of time input according to the TZDB specification greatly improves code readability. The comments explain the expected input format and the handling of special cases, making it easier for other developers to understand and maintain the code.

Furthermore, the code now handles the special case of "-" input, which represents 00:00. This ensures compliance with the TZDB specification and prevents potential parsing errors, enhancing the robustness of the parsing process.

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314-317: Comments enhance code readability and understanding of zone character handling!

The addition of comments explaining the handling of zone characters according to the TZDB specification significantly improves code readability. The comments clarify the meaning of each zone character and how they are mapped to their corresponding time types (standard, UTC, or wall time).

The code correctly implements the mapping of zone characters as per the specification, ensuring accurate parsing and interpretation of the input data.

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576-597: Input handling enhancements improve parsing consistency and accuracy!

The improvements to the input handling in this code segment are commendable. Trimming leading and trailing whitespace from each line ensures consistent parsing of the input data, regardless of the presence of extra whitespace. This enhances the robustness of the parsing process and reduces the likelihood of parsing errors caused by inconsistent whitespace.

The addition of comments explaining the handling of comments and blank lines in the input, according to the TZDB specification, greatly improves code readability. The comments clarify the rules for ignoring comments and blank lines, making it easier for other developers to understand and maintain the code.

Furthermore, the use of a StringTokenizer with the specified delimiters ensures accurate splitting of the input line into fields. The delimiters take into account the various whitespace characters mentioned in the specification, guaranteeing consistent and reliable parsing of the input data.

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Line range hint 612-628: Parsing logic enhanced with lookup structures and clarifying comments!

The enhancements to the parsing logic in this code segment are noteworthy. The addition of comments explaining the case-insensitivity and abbreviation rules for names, according to the TZDB specification, greatly improves code readability. The comments clarify the expected format and handling of names, making it easier for other developers to understand and maintain the code.

Moreover, the use of the new lookup structures (RULE_LOOKUP, ZONE_LOOKUP, LINK_LOOKUP) to determine the type of input line is a significant improvement. By replacing string comparisons with simple lookups, the parsing logic becomes more efficient and readable, reducing the likelihood of errors and making the code easier to follow.

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657-658: ScopedForTesting annotation improves code clarity and maintainability!

The addition of the ScopedForTesting annotation to the DateTimeOfYear class is a welcome improvement. This annotation clearly indicates that the class is intended for testing purposes only, preventing its accidental use in production code.

By explicitly marking the class as a testing utility, the code becomes more readable and maintainable. Developers can easily identify the purpose of the class and avoid using it in inappropriate contexts, reducing the risk of bugs and improving overall code quality.

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Line range hint 688-695: Case-insensitive parsing improves robustness and compliance with TZDB specification!

The modification to the parsing logic in the DateTimeOfYear class, which now converts the input to lowercase before performing string comparisons, is a valuable improvement. By ensuring case-insensitive parsing, the code adheres to the requirements of the TZDB specification, enhancing its compliance and compatibility with the expected input format.

This change also improves the robustness of the parsing process, reducing the likelihood of parsing errors caused by case mismatches. The code becomes more resilient to variations in the input data, providing a more reliable and consistent parsing experience.

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716-717: Comments clarify time input handling and improve code readability!

The addition of comments clarifying the handling of time input as a duration from 00:00, rather than a specific time, is a valuable improvement to the code's readability. These comments help developers understand the expected input format and the interpretation of time values according to the TZDB specification.

By explicitly stating the difference between the TZDB specification and the implementation's handling of time input, the comments reduce confusion and potential misinterpretation of the code. Developers can now clearly understand how the time values are processed and what assumptions are made, leading to more accurate and maintainable code.

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