feat: derive versionName/versionCode from the v* tag

.github/workflows/release.yml

@@ -40,6 +40,24 @@ jobs:
       - name: Build release APK
         run: ./gradlew :app:assembleRelease --no-daemon --stacktrace
 
+      # The APK's versionName is git-derived (app/build.gradle.kts), so a
+      # mismatch here means the checkout wasn't at the tag (workflow_dispatch
+      # on a moving branch, or describe picked an older tag). Fail before the
+      # release is published rather than ship a mislabelled APK.
+      - name: Verify APK version matches the tag
+        if: startsWith(github.ref, 'refs/tags/v')
+        run: |
+          set -e
+          tag="${GITHUB_REF_NAME#v}"
+          aapt="$(ls $ANDROID_HOME/build-tools/*/aapt2 | sort -V | tail -1)"
+          apk="$(ls app/build/outputs/apk/release/*.apk | head -1)"
+          apk_version="$("$aapt" dump badging "$apk" | sed -n "s/^package:.*versionName='\([^']*\)'.*/\1/p" | head -1)"
+          echo "tag: $tag   apk: $apk_version"
+          if [ "$apk_version" != "$tag" ]; then
+            echo "::error::APK versionName ($apk_version) does not match the tag being released (v$tag)"
+            exit 1
+          fi
+
       - name: Rename APK with tag
         run: |
           tag="${GITHUB_REF_NAME:-untagged}"

app/build.gradle.kts

@@ -1,5 +1,32 @@
 import org.gradle.api.tasks.Copy
 
+// ── Version from the v* tag (single source of truth) ────────────────────────
+// versionName = the most recent v* tag (via git describe); versionCode = the
+// number of commits since the tag began, plus a base, so it is deterministic
+// and strictly monotonic across builds without manual bumping — versionName
+// sat at "0.1.0" for eight releases because nothing forced the bump.
+// Tarball/no-git builds fall back to the constants below; keep them at the
+// last released values.
+fun gitVersionName(fallback: String): String {
+    val describe = try {
+        val p = ProcessBuilder("git", "describe", "--tags", "--match", "v*")
+            .directory(rootDir).redirectErrorStream(true).start()
+        p.inputStream.bufferedReader().readText().trim().also { p.waitFor() }
+    } catch (_: Exception) { "" }
+    return if (describe.startsWith("v")) describe.removePrefix("v") else fallback
+}
+
+fun gitVersionCode(base: Int, fallback: Int): Int {
+    // Count commits since the first commit reachable from HEAD; the base keeps
+    // historical codes (0.1.8 shipped as 8) below any git-derived value.
+    val count = try {
+        val p = ProcessBuilder("git", "rev-list", "--count", "HEAD")
+            .directory(rootDir).redirectErrorStream(true).start()
+        p.inputStream.bufferedReader().readText().trim().toIntOrNull().also { p.waitFor() }
+    } catch (_: Exception) { null }
+    return base + (count ?: (fallback - base))
+}
+
 plugins {
     alias(libs.plugins.android.application)
     alias(libs.plugins.kotlin.android)
@@ -15,8 +42,8 @@ android {
         applicationId = "at.dasher.android"
         minSdk = 24
         targetSdk = 35
-        versionCode = 8
-        versionName = "0.1.8"
+        versionCode = gitVersionCode(base = 1000, fallback = 8)
+        versionName = gitVersionName(fallback = "0.1.8")
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"