refactor!: remove deprecated divisionPolicy config and averageDeci

.github/pull_request_template.md

@@ -10,4 +10,4 @@
 
 - [ ] All tests pass (`./gradlew allTests`)
 - [ ] Lint passes (`./gradlew ktlintCheck`)
-- [ ] API compatibility verified (`./gradlew apiCheck`)
+- [ ] API compatibility verified (`./gradlew checkKotlinAbi`)

.github/workflows/build.yml

@@ -48,7 +48,7 @@ jobs:
         run: ./gradlew :deci:ktlintCheck
 
       - name: API compatibility check
-        run: ./gradlew :deci:apiCheck
+        run: ./gradlew :deci:checkKotlinAbi
 
       - name: Run JVM tests
         run: ./gradlew :deci:jvmTest

CHANGELOG.md

@@ -1,6 +1,38 @@
 # Changelog
 
-## [Unreleased]
+## [0.3.0] - 2026-06-09
+
+### Changed
+
+- **The `/` and `%` operators are now fixed to `DeciContext.DEFAULT`.** Behaviour
+  is unchanged for any code that never reassigned the (now-removed) global
+  `divisionPolicy`: bare division still yields 20 fractional digits with
+  `HALF_UP` rounding, and `%` (which is computed via `/`) is likewise unaffected.
+
+- **Migrated to the Kotlin Gradle plugin's built-in ABI validation — no public
+  API or runtime changes.** Dropped the deprecated standalone
+  `org.jetbrains.kotlinx:binary-compatibility-validator` plugin in favour of the
+  Kotlin Gradle plugin's `abiValidation { }` DSL. The `apiDump` / `apiCheck`
+  tasks are replaced by `updateKotlinAbi` / `checkKotlinAbi`, and the reference
+  dump now lives at `deci/api/jvm/deci.api` (JVM) plus `deci/api/deci.klib.api`
+  (Kotlin/Native, JS, and Wasm). Removed the `binary-compatibility-validator`
+  version and `bcv-gradle-plugin` version-catalog entries.
+
+### Removed
+
+- **Deprecated division-policy configuration removed (breaking).** Deleted
+  `DeciConfiguration.divisionPolicy`, `DeciConfiguration.resetDivisionPolicy()`,
+  and the `DeciDivisionPolicy` class. The `/` operator no longer reads a global
+  mutable policy; it always divides with `DeciContext.DEFAULT` (20 fractional
+  digits, `HALF_UP`) — identical to the previous out-of-the-box default. To
+  customise division scale or rounding, pass an explicit context per call:
+  `a.divide(b, DeciContext.CURRENCY_USD)` or
+  `a.divide(b, scale = 4, roundingMode = RoundingMode.HALF_EVEN)`.
+  `DeciConfiguration.logSink` / `disableLogging()` are unaffected.
+
+- **`Iterable<Deci>.averageDeci()` removed (breaking).** Use
+  `Iterable<Deci>.mean()` from `org.kimplify.deci.statistics` instead — a drop-in
+  replacement with the same signature and semantics: `values.mean(context)`.
 
 ## [0.2.2] - 2026-06-05
 

CLAUDE.md

@@ -113,19 +113,19 @@ val expected = 0.10.toDecimal()
 ./gradlew publishToMavenLocal
 
 # Generate API binary-compatibility dump
-./gradlew apiDump
+./gradlew updateKotlinAbi
 
 # Check for binary-compatibility regressions
-./gradlew apiCheck
+./gradlew checkKotlinAbi
 ```
 
 ---
 
 ## API Stability
 
-- This library uses [kotlin-binary-compatibility-validator](https://github.com/Kotlin/binary-compatibility-validator).
-- Run `./gradlew apiDump` after any public API change and commit the updated `.api` file.
-- `./gradlew apiCheck` runs in CI and will fail the build on unintentional API changes.
+- This library uses the Kotlin Gradle plugin's [built-in ABI validation](https://kotlinlang.org/docs/whatsnew2120.html#binary-compatibility-validation-in-the-kotlin-gradle-plugin) (`abiValidation`).
+- Run `./gradlew updateKotlinAbi` after any public API change and commit the updated dump files under `deci/api/` (`jvm/deci.api` for JVM, `deci.klib.api` for the Kotlin/Native, JS, and Wasm targets).
+- `./gradlew checkKotlinAbi` runs in CI and will fail the build on unintentional API changes.
 - Mark experimental APIs with `@ExperimentalDeciApi` and require opt-in.
 
 ---

README.MD

@@ -169,17 +169,19 @@ Values serialize as JSON **strings** to preserve trailing zeros and avoid lossy
 
 ## Configuration
 
+Division scale and rounding are chosen per call via `DeciContext` — there is no global
+mutable division policy. The `/` operator uses `DeciContext.DEFAULT` (20 fractional
+digits, `HALF_UP`); pass an explicit context or `scale`/`roundingMode` for anything else:
+
 ```kotlin
-DeciConfiguration.divisionPolicy = DeciDivisionPolicy(
-    fractionalDigits = 6,
-    roundingMode = RoundingMode.HALF_UP
-)
+Deci("10") / Deci("3")                                   // DeciContext.DEFAULT
+Deci("10").divide(Deci("3"), DeciContext.CURRENCY_USD)   // 2 digits, HALF_UP
+Deci("10").divide(Deci("3"), scale = 4, roundingMode = RoundingMode.HALF_EVEN)
 
 DeciConfiguration.logSink = DeciLogSink { tag, message ->
     println("[$tag] $message")
 }
 
-DeciConfiguration.resetDivisionPolicy()
 DeciConfiguration.disableLogging()
 ```
 

build-logic/build.gradle.kts

@@ -4,5 +4,4 @@ dependencies {
     implementation(libs.kotlin.gradle.plugin)
     implementation(libs.android.gradle.plugin)
     implementation(libs.ktlint.gradle.plugin)
-    implementation(libs.bcv.gradle.plugin)
 }

build-logic/src/main/kotlin/deci.kmp.library.gradle.kts

@@ -1,15 +1,19 @@
-@file:OptIn(org.jetbrains.kotlin.gradle.ExperimentalWasmDsl::class)
+@file:OptIn(
+    org.jetbrains.kotlin.gradle.ExperimentalWasmDsl::class,
+    org.jetbrains.kotlin.gradle.dsl.abi.ExperimentalAbiValidation::class,
+)
 
 plugins {
     id("org.jetbrains.kotlin.multiplatform")
     id("com.android.kotlin.multiplatform.library")
     id("org.jlleitschuh.gradle.ktlint")
-    id("org.jetbrains.kotlinx.binary-compatibility-validator")
 }
 
 kotlin {
     jvmToolchain(21)
 
+    abiValidation {}
+
     jvm()
     js { browser() }
     wasmJs { browser() }