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fix: allow overriding testKit in ScalaTestWithActorTestKit - #3610
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He-Pin merged 3 commits intoOct 10, 2026
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Motivation: A spec that overrides `testKit` with a `val`, e.g. `override val testKit = ActorTestKit()`, fails with a NullPointerException. `ScalaTestWithActorTestKitBase.patience` is a strict `val` that reads `testKit.testKitSettings` while the trait is initialized, before the subclass has assigned its overriding `testKit`. Modification: Make `patience` a `lazy val` so it is computed on first use, after construction. Add `ScalaTestWithActorTestKitSpec`. Result: Specs can override `testKit` with a `val`, and `patience` uses the overriding testkit's `DefaultTimeout`. Tests: - `actor-testkit-typed/Test/testOnly ...ScalaTestWithActorTestKitSpec` without the fix: failed with NullPointerException in `ScalaTestWithActorTestKitBase.testKit()` - `actor-testkit-typed/Test/testOnly org.apache.pekko.actor.testkit.typed.scaladsl.*` with the fix: 99 passed on 2.13.18 and 3.3.8 - `actor-testkit-typed/mimaReportBinaryIssues`: passed on 2.13.18 and 3.3.8 - scalafmt run on changed files References: Fixes apache#1140
Motivation: Making `patience` a `lazy val` broke every subclass that overrides it with `override implicit val patience`, e.g. `ReplicatedShardingSpec`, because a strict `val` cannot override a `lazy val`. User specs doing the same would no longer compile. Modification: Make `patience` a `def` instead. It is still evaluated on access rather than during trait initialization, and can be overridden by a `val`, `lazy val` or `def`. Result: Overriding `testKit` with a `val` works and existing `patience` overrides still compile. Tests: - `actor-testkit-typed/testOnly *ScalaTestWithActorTestKitSpec`: passed - `Test/compile` for cluster-sharding-typed, stream-tests, coordination, remote and actor-tests: passed - `actor-testkit-typed/mimaReportBinaryIssues`: passed - scalafmt run on changed files References: Fixes apache#1140
Motivation: The Check / Binary Compatibility job fails on Scala 3. Making `patience` a `def` leaves `ScalaTestWithActorTestKitBase` with no fields, so Scala 3 no longer emits the trait's synthetic `$init$`. Modification: Add a 2.0.x MiMa exclude for `ScalaTestWithActorTestKitBase.$init$`. Result: MiMa passes for actor-testkit-typed on Scala 2.13 and 3. Tests: - `++3.3.8 actor-testkit-typed/mimaReportBinaryIssues`: failed without the filter with the same error as CI, passed with it - `actor-testkit-typed/mimaReportBinaryIssues` (2.13): passed References: Refs apache#1140
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LGTM. Making patience a def correctly avoids the initialization-order NPE when a spec overrides testKit with a val, while keeping existing override implicit val patience source-compatible. The MiMa filter for the dropped Scala 3 $init$ is in place and the new spec pins the behavior.
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Motivation
A spec that overrides
testKitwith aval, e.g.override val testKit = ActorTestKit(), fails with aNullPointerException.ScalaTestWithActorTestKitBase.patienceis a strictvalthat readstestKit.testKitSettingswhile the trait is being initialized, before the subclass has assigned its overridingtestKit.Modification
patienceadef, so it is computed on access, after construction. Adef(rather than alazy val) keeps existingoverride implicit val patienceoverrides compiling.ScalaTestWithActorTestKitSpec.Result
Specs can override
testKitwith aval, andpatienceuses the overriding testkit'sDefaultTimeout.Tests
actor-testkit-typed/Test/testOnly ...ScalaTestWithActorTestKitSpecwithout the fix: failed withNullPointerExceptioninScalaTestWithActorTestKitBase.testKit()actor-testkit-typed/Test/testOnly org.apache.pekko.actor.testkit.typed.scaladsl.*with the fix: 99 passed on 2.13.18 and 3.3.8actor-testkit-typed/mimaReportBinaryIssues(baseline 1.0.0): passed on 2.13.18 and 3.3.8References
Fixes #1140