Compile build-logic with JDK 17 so the build runs on a JDK 17 daemon [CLF-286] - #1561
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build-logic is on the buildscript classpath, so the Gradle daemon loads its classes directly. Compiling it with the jdk-toolchain (21) meant the daemon itself had to be JDK 21, and building on a stock JDK 17 environment failed with: Could not resolve project :build-logic. > Dependency requires at least JVM runtime version 21. This build uses a Java 17 JVM. The 21 was inherited from the libraries' toolchain, which conflated two different things: the JDK the libraries compile with (a real Gradle toolchain, forked by the daemon) and the JDK the daemon must be able to load. Only the latter constrains JAVA_HOME. Split them with a new jdk-buildLogic version, set to 17 — the floor Gradle 9 and AGP 8 already require. The libraries still compile with the JDK 21 toolchain, so parity with android-register's compile JDK is preserved, and published bytecode is unchanged (jdk-target stays at 11). Also document the three JDK versions in CONTRIBUTING.md, which previously didn't mention any JDK requirement. Co-Authored-By: Claude <noreply@anthropic.com>
zach-klippenstein
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zach-klippenstein
enabled auto-merge
August 18, 2026 18:43
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Fine with me but also fine keeping it JDK 21 |
handstandsam
approved these changes
Aug 18, 2026
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Building workflow-kotlin on a stock JDK 17 environment (e.g. Square's
sa-toolsdefault of Azul 17) fails immediately:Cause
jdk-toolchain = "21"was consumed in two structurally different places:KotlinCommonSettings.kt—jvmToolchain(21)for library/sample modulesbuild-logic/build.gradle.kts— build-logic's own toolchainOnly the second forces
JAVA_HOMEto be 21. Nothing in build-logic needs Java 21 language features — it just inherited the libraries' value, conflating "JDK the libraries compile with" and "JDK the daemon must be able to load".This is why android-register builds fine on JDK 17 while workflow did not: android-register uses toolchains for compilation and keeps its daemon on 17.
Fix
Split the two concepts in the version catalog:
jdk-target(11)jdk-toolchain(21)jdk-buildLogic(17)17 is the natural floor, since Gradle 9.3.1 and AGP 8.13 both already require JDK 17+.
CONTRIBUTING.mdpreviously documented no JDK requirement at all, which is what made this bite silently; it now explains all three versions.Verification
Run locally on both JDKs:
./gradlew test --continueapiCheck artifactsCheck dependencyGuardPublished bytecode is unchanged —
workflow-coreclasses are still major version 55 (Java 11), matchingjdk-target.build-logicmoves from 65 (Java 21) to 61 (Java 17).Fixes CLF-286.