Target Java 1.8 for Circuit published libraries (from Java 11) (#1378)

Our problem is we want to use Circuit in a SDK potentially used by AGP
4.0 / Java 8 consumers (Unity). Since Circuit target Java 11 we can't
build the consumer app. Since current androidx libraries are built for
Java 8 it makes sense to downgrade from Java 11 to Java 8 (until
androidx team decide to bump to Java 11).

In this change only published libraries are impacted. Published library
mean a `POM_ARTIFACT_ID` property exists.

The change was tested successfully using a Unity 2020 project with the
Circuit counter sample added to our SDK.

build.gradle.kts

@@ -139,8 +139,12 @@ fun Project.configureComposeBom(dependencyHandler: DependencyHandler) {
 }
 
 val jvmTargetVersion = libs.versions.jvmTarget
+val publishedJvmTargetVersion = libs.versions.publishedJvmTarget
 
 subprojects {
+  val isPublished = project.hasProperty("POM_ARTIFACT_ID")
+  val jvmTargetProject = if (isPublished) publishedJvmTargetVersion else jvmTargetVersion
+
   pluginManager.withPlugin("java") {
     configure<JavaPluginExtension> {
       toolchain {
@@ -151,7 +155,9 @@ subprojects {
     }
 
     tasks.withType<JavaCompile>().configureEach {
-      options.release.set(jvmTargetVersion.map(String::toInt))
+      options.release.set(
+        jvmTargetProject.map(JavaVersion::toVersion).map { it.majorVersion.toInt() }
+      )
     }
 
     // This is the default base plugin applied on all projects, so safe to add this hook here
@@ -167,7 +173,12 @@ subprojects {
       compilerOptions {
         allWarningsAsErrors.set(true)
         if (this is KotlinJvmCompilerOptions) {
-          jvmTarget.set(jvmTargetVersion.map(JvmTarget::fromTarget))
+          jvmTarget.set(
+            jvmTargetProject
+              .map(JavaVersion::toVersion)
+              .map { it.toString() }
+              .map(JvmTarget::fromTarget)
+          )
           // Stub gen copies args from the parent compilation
           if (this@configureEach !is KaptGenerateStubsTask) {
             freeCompilerArgs.addAll(
@@ -340,8 +351,8 @@ subprojects {
     }
 
     compileOptions {
-      sourceCompatibility = JavaVersion.VERSION_11
-      targetCompatibility = JavaVersion.VERSION_11
+      sourceCompatibility = jvmTargetProject.map(JavaVersion::toVersion).get()
+      targetCompatibility = jvmTargetProject.map(JavaVersion::toVersion).get()
     }
 
     lint {

gradle/libs.versions.toml

@@ -32,6 +32,7 @@ dokka = "1.9.20"
 eithernet = "1.8.1"
 jdk = "21"
 jvmTarget = "11"
+publishedJvmTarget = "1.8"
 kct = "0.4.1"
 kotlin = "1.9.23"
 kotlinpoet = "1.16.0"