[AURON #2130] Implement native function of weekofyear

[weimingdiit]

Which issue does this PR close?

Closes ##2130

Rationale for this change

To improve compatibility with Spark SQL date functions, we should implement weekofyear() with Spark-compatible semantics.

Expected behavior

Function name: weekofyear(expr)

Return type: INT

Week semantics:

• A week starts on Monday
• Week 1 is the first week of the year with more than 3 days
• This matches Spark’s ISO-style week numbering behavior

Examples:

• weekofyear('2009-07-30') -> 31
• weekofyear('2016-01-01') -> 53
• weekofyear('2017-01-01') -> 52

Supports: DATE, TIMESTAMP, and compatible string/date inputs consistent with existing date extraction functions

Additional expectations:

• Null-safe: returns NULL if input is NULL
• Array and scalar inputs: consistent with existing native date extraction functions
• Cross-year boundary behavior should match Spark semantics exactly

What changes are included in this PR?

This PR adds native support for the weekofyear() function with Spark-compatible semantics.
The following changes are included:

• Added native implementation of spark_weekofyear() in the expression layer
• Added WeekOfYear expression support in NativeConverters for proper Spark -> native translation
• Registered Spark_WeekOfYear in native function dispatch
• Added unit tests to verify correctness for:
  • normal date inputs
  • cross-year boundary cases
  • Spark-compatible ISO week numbering semantics
  • null input handling

Are there any user-facing changes?

NO.

How was this patch tested?

• Added and ran targeted Rust unit tests for spark_weekofyear()
• Verified expected results for representative Spark-compatible cases such as:
  • weekofyear('2009-07-30') = 31
  • weekofyear('2016-01-01') = 53
  • weekofyear('2017-01-01') = 52

[Copilot]

Pull request overview

Implements native support for Spark-compatible weekofyear() to reduce Spark fallbacks and improve Spark SQL function parity in Auron’s native execution path.

Changes:

• Add Spark expression translation for WeekOfYear to a native ext scalar function (Spark_WeekOfYear).
• Implement spark_weekofyear() in the native Rust function layer and register it in the ext-function dispatcher.
• Add Spark-side integration coverage plus Rust unit test coverage for core ISO week semantics and null propagation.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
spark-extension/src/main/scala/org/apache/spark/sql/auron/NativeConverters.scala	Adds Spark WeekOfYear expression mapping to the native ext function Spark_WeekOfYear.
spark-extension-shims-spark/src/test/scala/org/apache/auron/AuronFunctionSuite.scala	Adds an integration test exercising weekofyear() via checkSparkAnswerAndOperator.
native-engine/datafusion-ext-functions/src/spark_dates.rs	Adds spark_weekofyear() implementation (ISO week) plus a unit test.
native-engine/datafusion-ext-functions/src/lib.rs	Registers Spark_WeekOfYear in the native ext function dispatcher.

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[ShreyeshArangath]

LGTM

[slfan1989]

@weimingdiit Thanks for the contribution! @ShreyeshArangath @yew1eb Thanks for the review!

[weimingdiit]

@slfan1989 Thanks for your merge! @ShreyeshArangath @yew1eb Thanks for the review!