ci(publish): build & publish the skainet-backend-jni-cpu AAR on release (#946)

.github/workflows/publish.yml

@@ -21,6 +21,12 @@ name: release
 #     resources.srcDir(nativeResourcesRoot) on jvmMain picks them all
 #     up into the published JAR.
 #
+# The publish job also builds and publishes the skainet-backend-jni-cpu AAR
+# (Android JNI kernel provider). Its native .so's are cross-compiled by the
+# NDK during `./gradlew publish`, so the publish runner sets up the Android
+# SDK + a pinned NDK (see the publish job) — independent of the build-native
+# matrix above, which only produces the FFM shared libs.
+#
 # Linux ARM64 is intentionally absent: Kotlin/Native plugin 2.3.21
 # doesn't support `linux aarch64` as a HOST target ("Unknown host
 # target" — see SKaiNET PR #577). Linux ARM64 consumers fall back
@@ -139,6 +145,20 @@ jobs:
           distribution: 'zulu'
           java-version: 25
 
+      # `./gradlew publish` now includes skainet-backend-jni-cpu (an Android
+      # library whose AAR carries NDK-built .so's). The publish runner therefore
+      # needs the Android SDK + a pinned NDK; without it the AAR's native build
+      # fails and the release ships no JNI artifact. The NDK version must match
+      # gradle/libs.versions.toml `android-ndk`.
+      - name: Set up Android SDK
+        uses: android-actions/setup-android@9fc6c4e9069bf8d3d10b2204b1fb8f6ef7065407 # v3.2.2
+
+      - name: Install pinned NDK
+        run: |
+          NDK_VERSION="$(grep -E '^android-ndk[[:space:]]*=' gradle/libs.versions.toml | sed -E 's/.*"([^"]+)".*/\1/')"
+          echo "Installing NDK ${NDK_VERSION}"
+          yes | sdkmanager "ndk;${NDK_VERSION}" >/dev/null
+
       - name: Validate signing configuration
         run: |
           if ! grep -Eq '^[[:space:]]*signAllPublications[[:space:]]*=[[:space:]]*true[[:space:]]*$' gradle.properties; then

CHANGELOG.md

@@ -2,6 +2,15 @@
 
 ## [Unreleased]
 
+### CI
+
+- **Release workflow publishes the `skainet-backend-jni-cpu` AAR.** `./gradlew publish` now
+  includes the Android JNI kernel module, whose AAR carries NDK-cross-built `.so`s; the publish
+  job gains Android SDK + a pinned NDK setup so the native build succeeds on the release runner
+  (previously the release would ship no JNI artifact, or fail). The NDK version is pinned in
+  `gradle/libs.versions.toml` (`android-ndk`) and referenced by the module's `ndkVersion` and the
+  workflow, so local and CI builds are reproducible. (#946)
+
 ### Added
 
 - **NEON body for the Q4_0 matmul kernel.** `skainet_q4_0_matmul` was the only priority

gradle/libs.versions.toml

@@ -10,6 +10,10 @@ kotlinxCoroutines = "1.11.0"
 kotlinBrowser = "0.5.0"
 android-minSdk = "24"
 android-compileSdk = "36"
+# NDK for skainet-backend-jni-cpu's externalNativeBuild. Pinned so the AAR's
+# .so's build reproducibly on dev machines and the release runner. r28+ links
+# 16 KB-page-aligned .so's by default (Android 15+ requirement).
+android-ndk = "28.2.13676358"
 kotlinxSerializationJson = "1.11.0"
 ktorClientCore = "3.5.2"
 ktorClientPlugins = "3.1.1"

skainet-backends/skainet-backend-jni-cpu/build.gradle.kts

@@ -23,6 +23,9 @@ plugins {
 android {
     namespace = "sk.ainet.exec.kernel.jni"
     compileSdk = libs.versions.android.compileSdk.get().toInt()
+    // Pinned NDK so the AAR's .so's build reproducibly locally and on the
+    // release runner (AGP provisions it via sdkmanager when absent).
+    ndkVersion = libs.versions.android.ndk.get()
 
     defaultConfig {
         minSdk = libs.versions.android.minSdk.get().toInt()