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Motivation: On Scala 3, `Logging(system, getClass)` fails to compile with "Cannot find LogSource for Class[? <: Foo]". `getClass` returns a wildcard class type, which Scala 3 does not match against `LogSource.fromAnyClass[T]: LogSource[Class[T]]`. Scala 2.13 accepts it. Modification: - Make `object LogSource` extend a new `LogSourceCompat` trait. - The Scala 3 `LogSourceCompat` adds a lower priority `fromAnySubClass[T]: LogSource[Class[? <: T]]` implicit; the Scala 2.13 version is empty because Scala 2 reports that implicit as ambiguous with `fromAnyClass`. - `fromAnyClass` is unchanged; changing its signature instead fails MiMa with an IncompatibleSignatureProblem. - Add `LogSourceSpec`. Result: `Logging(system, getClass)` and `LogSource(getClass, system)` compile on Scala 3. Tests: - `actor-tests/Test/testOnly org.apache.pekko.event.LogSourceSpec` on Scala 3.3.8 without the fix: compile error "Cannot find LogSource for Class[? <: ...LogsWithGetClass]" - `actor-tests/Test/testOnly org.apache.pekko.event.LogSourceSpec org.apache.pekko.event.LoggerSpec` with the fix: passed on 2.13.18 and 3.3.8 - `actor/mimaReportBinaryIssues`: passed on 2.13.18 and 3.3.8 - scalafmt run on changed files References: Fixes apache#1538
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Motivation
On Scala 3,
Logging(system, getClass)fails to compile withCannot find LogSource for Class[? <: Foo].getClassreturns a wildcard class type, which Scala 3 does not match againstLogSource.fromAnyClass[T]: LogSource[Class[T]]. Scala 2.13 accepts the same code.Modification
object LogSourcenow extends a newLogSourceCompattrait.LogSourceCompatadds a lower priorityfromAnySubClass[T]: LogSource[Class[? <: T]]implicit. The Scala 2.13 version is empty, because Scala 2 reports that implicit as ambiguous withfromAnyClass.fromAnyClassis unchanged. Changing its signature toLogSource[Class[? <: T]]also works, but MiMa reports anIncompatibleSignatureProblem.LogSourceSpec.Result
Logging(system, getClass)andLogSource(getClass, system)compile on Scala 3.Tests
actor-tests/Test/testOnly org.apache.pekko.event.LogSourceSpecon Scala 3.3.8 without the fix: compile errorCannot find LogSource for Class[? <: ...LogsWithGetClass]actor-tests/Test/testOnly org.apache.pekko.event.LogSourceSpec org.apache.pekko.event.LoggerSpecwith the fix: passed on 2.13.18 and 3.3.8actor/mimaReportBinaryIssues: passed on 2.13.18 and 3.3.8References
Fixes #1538