Fix BaseGeometryFunction.hashCode to be consistent with equals - #1203
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dr-jts merged 2 commits intoJun 17, 2026
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BaseGeometryFunction.equals() defines two functions as equal when they have the same signature (name, parameter types and return type), and explicitly ignores parameter names. hashCode(), however, also mixed in the parameter names, so two functions that are equal but differ only in their parameter names produced different hash codes -- violating the Object.equals/hashCode contract and causing them to misbehave as keys in hash-based collections. Drop parameterNames from hashCode() so it uses exactly the fields equals() compares. Adds a test for the equals/hashCode contract. (compareTo() remains ordered by name and return type only -- coarser than equals(), which the Comparable contract permits -- so it is left unchanged.) Co-authored-by: Claude <noreply@anthropic.com>
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BaseGeometryFunction.equals()defines two functions as equal when they have the same signature (name, parameter types and return type), and explicitly ignores parameter names.hashCode(), however, also mixed in the parameter names (Arrays.hashCode(parameterNames)), so two functions that are equal but differ only in their parameter names produced different hash codes — violating theObject.equals/hashCodecontract and causing them to misbehave as keys in hash-based collections.Changes Made:
parameterNamesfromBaseGeometryFunction.hashCode()so it uses exactly the fieldsequals()compares (name, parameter types, return type).equals/hashCodecontract.compareTo()remains ordered by name and return type only — coarser thanequals(), which theComparablecontract permits — so it is left unchanged.This was found by a conformance sweep of the
jts-ioandjts-appmodules forequals/hashCode/Comparableinconsistencies;jts-iowas clean.