chore(build): parallel configuration cache, and make version assignment IP-safe

Enables org.gradle.configuration-cache.parallel, and removes the one thing in
this build that Isolated Projects rejects.

The root build script set the git-derived version through `allprojects { }`.
Under Isolated Projects that fails outright — "Project ':' cannot access
'Project.version' functionality on subprojects via 'allprojects'" — because the
root project may not reach into its subprojects' state. The supported
equivalent is gradle.lifecycle.beforeProject in settings.gradle.kts, which
needs no cross-project access, so the derivation moves there wholesale.

One subtlety worth the comment it carries: the beforeProject lambda must close
over a *local* copy of the resolved version. A top-level `val` in a settings
script is a field of the script object, so referencing it directly makes the
configuration cache try to serialise the script itself and fail with "cannot
serialize Gradle script object references".

Isolated Projects is still not enabled, and the remaining blocker is not ours:
KGP's WasmNpmResolverPlugin reaches from :sample into the root project
("Project ':sample' cannot access 'Project.plugins' functionality on another
project ':'"). gradle.properties records this so the next reader does not
rediscover it. With the build's own side now clean, turning the feature on is a
one-line change once JetBrains isolates the Wasm/npm plugins.

Verified with spotlessCheck detektAll allTests apiCheck koverVerify.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: jamesarich

build.gradle.kts

@@ -16,39 +16,6 @@ plugins {
     alias(libs.plugins.kover)
 }
 
-// ---------------------------------------------------------------------------
-// Version: derived from the latest git tag (e.g. v0.3.6 → 0.3.6).
-// Between tags: next patch + "-SNAPSHOT" (e.g. v0.3.6-4-gabcdef → 0.3.7-SNAPSHOT).
-// Overridable via -PVERSION_NAME=... (used by CI snapshot publishing).
-// ---------------------------------------------------------------------------
-val gitVersion: Provider<String> = providers.exec {
-    commandLine("git", "describe", "--tags", "--match", "v*")
-    isIgnoreExitValue = true
-}.standardOutput.asText.map { raw ->
-    val desc = raw.trim()
-    if (desc.isBlank()) {
-        return@map providers.gradleProperty("VERSION_NAME").getOrElse("0.0.0-SNAPSHOT")
-    }
-    val stripped = desc.removePrefix("v")
-    if ('-' in stripped) {
-        // Not on an exact tag — compute next-patch SNAPSHOT
-        val base = stripped.substringBefore('-')
-        val parts = base.split('.').map(String::toInt)
-        "${parts[0]}.${parts[1]}.${parts[2] + 1}-SNAPSHOT"
-    } else {
-        stripped
-    }
-}
-
-val resolvedVersion: String =
-    providers.gradleProperty("VERSION_NAME")
-        .orElse(gitVersion)
-        .get()
-
-allprojects {
-    version = resolvedVersion
-}
-
 // ---------------------------------------------------------------------------
 // Aggregate API docs (Dokka) and coverage (Kover) across the published library
 // modules. The ≥80% coverage gate is enforced on the merged report so that

gradle.properties

@@ -2,7 +2,13 @@
 org.gradle.jvmargs=-Xmx2048M -Dfile.encoding=UTF-8
 org.gradle.caching=true
 org.gradle.configuration-cache=true
+org.gradle.configuration-cache.parallel=true
 org.gradle.parallel=true
+#Isolated Projects is NOT enabled, and the blocker is not ours: KGP's
+#WasmNpmResolverPlugin reaches from :sample into the root project
+#("Project ':sample' cannot access 'Project.plugins' functionality on another project ':'").
+#The build's own side is already IP-ready — see the beforeProject version assignment in
+#settings.gradle.kts — so this is a one-line flip once KGP's Wasm/npm plugins isolate cleanly.
 org.gradle.vfs.watch=true
 org.gradle.welcome=never
 #Kotlin

settings.gradle.kts

@@ -23,6 +23,49 @@ dependencyResolutionManagement {
     }
 }
 
+// ---------------------------------------------------------------------------
+// Version: derived from the latest git tag (e.g. v0.3.6 -> 0.3.6).
+// Between tags: next patch + "-SNAPSHOT" (e.g. v0.3.6-4-gabcdef -> 0.3.7-SNAPSHOT).
+// Overridable via -PVERSION_NAME=... (used by CI snapshot publishing).
+//
+// Assigned from settings via gradle.lifecycle.beforeProject rather than an
+// `allprojects { }` block in the root build script: under Isolated Projects the
+// root project may not reach into its subprojects' state, and setting `version`
+// that way fails configuration outright. beforeProject is the supported
+// equivalent and needs no cross-project access.
+// ---------------------------------------------------------------------------
+val gitVersion: Provider<String> = providers.exec {
+    commandLine("git", "describe", "--tags", "--match", "v*")
+    isIgnoreExitValue = true
+}.standardOutput.asText.map { raw ->
+    val desc = raw.trim()
+    if (desc.isBlank()) {
+        return@map providers.gradleProperty("VERSION_NAME").getOrElse("0.0.0-SNAPSHOT")
+    }
+    val stripped = desc.removePrefix("v")
+    if ('-' in stripped) {
+        // Not on an exact tag - compute next-patch SNAPSHOT
+        val base = stripped.substringBefore('-')
+        val parts = base.split('.').map(String::toInt)
+        "${parts[0]}.${parts[1]}.${parts[2] + 1}-SNAPSHOT"
+    } else {
+        stripped
+    }
+}
+
+val resolvedVersion: String =
+    providers.gradleProperty("VERSION_NAME")
+        .orElse(gitVersion)
+        .get()
+
+// Copied into a local before the lambda closes over it: a top-level `val` in a settings script is a
+// field of the script object, so referencing it directly would capture the script itself — which the
+// configuration cache cannot serialize ("cannot serialize Gradle script object references").
+run {
+    val projectVersion = resolvedVersion
+    gradle.lifecycle.beforeProject { version = projectVersion }
+}
+
 rootProject.name = "MQTTastic-Client-KMP"
 include(":core")
 include(":transport-tcp")