[GH-2830] Add Geography support for ST_Equals

[zhangfengcdt]

Did you read the Contributor Guide?

• Yes, I have read the Contributor Rules and Contributor Development Guide

Is this PR related to a ticket?

• Yes, and the PR name follows the format [GH-XXX] my subject. Closes #<issue_number>

What changes were proposed in this PR?

• Converts ST_Equals to InferredExpression for dual-dispatch (Geometry vs Geography)
• Follow-up to [GH-2830] Improve Geography query support - core #2831; L3 tier. ST_Equals in Predicates.scala is converted from ST_Predicate with CodegenFallback to InferredExpression(Predicates.equals, geography.Functions.equals).
  • JoinQueryDetector: moves ST_Equals out of getJoinDetection (it's no longer an ST_Predicate subtype) and adds a top-level case with the existing isGeographyInput guard, mirroring ST_Contains. Preserves today's Geometry-path join planning; Geography inputs fall back to row-by-row evaluation.

How was this patch tested?

• mvn clean test -pl common -am -Dtest=FunctionTest
• New Spark SQL cases in GeographyFunctionTest
• mvn spotless:apply run before commit; no format violations.

Did this PR include necessary documentation updates?

• Yes, I have updated the documentation.

[Copilot]

Pull request overview

Adds Geography support for ST_Equals by converting it to an InferredExpression (dual-dispatch Geometry vs Geography), while ensuring join planning remains Geometry-only and Geography joins fall back to Spark evaluation.

Changes:

• Convert ST_Equals from ST_Predicate to InferredExpression wired to both JTS (Predicates.equals) and S2 (geography.Functions.equals).
• Update JoinQueryDetector to keep Geometry join optimization for ST_Equals while skipping join planning when either side is GeographyUDT.
• Add Geography equality implementation + unit/integration tests and publish new Geography SQL docs for ST_Equals.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
spark/common/src/main/scala/org/apache/spark/sql/sedona_sql/expressions/Predicates.scala	Switch ST_Equals to dual-dispatch via InferredExpression (Geometry + Geography).
common/src/main/java/org/apache/sedona/common/geography/Functions.java	Add S2-based Functions.equals(Geography, Geography) implementation.
spark/common/src/main/scala/org/apache/spark/sql/sedona_sql/strategy/join/JoinQueryDetector.scala	Move ST_Equals join detection to top-level match with Geography guard (no Geography join planning).
common/src/test/java/org/apache/sedona/common/Geography/FunctionTest.java	Add unit tests for Functions.equals (points/polygon + null handling).
spark/common/src/test/scala/org/apache/sedona/sql/geography/GeographyFunctionTest.scala	Add Spark SQL integration tests for ST_Equals on Geography (point cases).
docs/api/sql/geography/Geography-Functions.md	Add ST_Equals to Geography function index.
docs/api/sql/geography/Geography-Functions/ST_Equals.md	New Geography SQL docs page for ST_Equals.

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