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Adding a New Correction Rule Type

Correction rules run before validation. They clean, normalize, and transform field values before business rules are applied.

Where Corrections Fit​

Built-in Correction Types​

Steps​

1. Add the enum value​

In FileSpec.kt, add to CorrectionType:

enum class CorrectionType {
    TRIM, PAD_LEFT, PAD_RIGHT, UPPER_CASE, LOWER_CASE, REGEX_REPLACE,
    COERCE_DATE, DEFAULT_IF_NULL,
    YOUR_NEW_TYPE   // ← add here
}

2. Add the when branch in CorrectionEngine​

fun applyCorrection(value: Any?, rule: CorrectionRule, fieldSpec: FieldSpec): Any? {
    return when (rule.correctionType) {
        CorrectionType.TRIM -> (value as? String)?.trim()
        // ... existing cases ...
        CorrectionType.YOUR_NEW_TYPE -> {
            // implement transformation
            value
        }
    }
}

3. Write tests using ShouldSpec​

class CorrectionEngineTest : ShouldSpec({

    val engine = CorrectionEngine()

    context("YOUR_NEW_TYPE correction") {
        should("transform value correctly") {
            val rule = CorrectionRule(
                ruleId = "test",
                field = "amount",
                correctionType = CorrectionType.YOUR_NEW_TYPE
            )
            engine.applyCorrection("input", rule, fieldSpec) shouldBe "expected output"
        }
    }
})
./gradlew :platform-core:test

Correction Rule Execution Order​

Rules are applied in applyOrder — the order they appear in the correctionRules list in the spec.

Checklist​

  • New enum value added to CorrectionType
  • when branch added in CorrectionEngine.applyCorrection()
  • ShouldSpec tests added to CorrectionEngineTest
  • AGENTS.md §6 updated