Add -Yfuture-lazy-vals for Scala 3 builds#1060
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Motivation: The Scala 3.3.8 compiler introduced the -Yfuture-lazy-vals flag (scala/scala3-lts#637) to optionally use VarHandle instead of sun.misc.Unsafe for lazy val implementation. This prepares libraries for upcoming JDK releases that restrict Unsafe access. Modification: Add -Yfuture-lazy-vals to Common.scala scalacOptions using the existing onlyOnScala3 helper. Result: pekko-http's Scala 3 build uses the future-proof VarHandle-based lazy val implementation, compatible with all JDK 9+ versions. Tests: - sbt "++3.3.8; http/compile" passed (exit 0, 66s) References: Refs scala/scala3-lts#637
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Motivation: The -Yfuture-lazy-vals flag added in 6d25f5e changes the Scala 3 bytecode generated for object lazy vals. As a side effect, the synthetic <clinit> static initializers on Directives, PathMatchers, and PathDirectives are no longer emitted, causing MiMa to flag three DirectMissingMethodProblem errors against the 1.0.0 baseline. These are compiler-internal initialization methods, not part of the public API, so the change is binary compatible in practice. Modification: Add a new mima-filters exclude file under 2.0.x.backwards.excludes/ to suppress the three <clinit> missing-method warnings on the Scala 3 build. Result: sbt "++3.3.8; http/mimaReportBinaryIssues" and validatePullRequest MiMa checks pass again. References: Refs apache#1060
pjfanning
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Jun 13, 2026
Motivation: Code review requested combining the two onlyOnScala3 calls into one. Modification: Merge "-Wconf:cat=deprecation:s" and "-Yfuture-lazy-vals" into a single onlyOnScala3(Seq(...)) call. Result: Cleaner build definition with both Scala 3 options in one place. Tests: Not run - build config only References: Refs apache#1060
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Motivation
The Scala 3.3.8 compiler introduced the
-Yfuture-lazy-valsflag (scala/scala3-lts#637) to optionally useVarHandleinstead ofsun.misc.Unsafefor lazy val implementation. This prepares libraries for upcoming JDK releases that restrictsun.misc.Unsafeaccess.Modification
Add
-Yfuture-lazy-valstoCommon.scalascalacOptions using the existingonlyOnScala3helper:Result
pekko-http's Scala 3 build uses the future-proof
VarHandle-based lazy val implementation, compatible with all JDK 9+ versions.Tests
sbt "++3.3.8; http/compile"— passed (exit 0, 66s, only pre-existing warnings)References
Refs scala/scala3-lts#637