build(android): install the debug build alongside release as its own app

Testing a debug build meant uninstalling the real one first: same
applicationId signed with a different key is INSTALL_FAILED_UPDATE_
INCOMPATIBLE, so every experiment cost the app's settings, credentials
and offline cache.

The debug build type now carries applicationIdSuffix ".debug" and
versionNameSuffix "-debug", so it installs as com.dtourolle.jellytau.debug
("JellyTau Debug", 0.5.5-debug) with its own data directory — two
independent apps on one device.

Only the *application* id is suffixed. Kotlin classes stay in the
`namespace` package com.dtourolle.jellytau, so the JNI loadClass lookups
in player/android/mod.rs, the manifest <service> entry and the R8 keep
rules are untouched, and the FileProvider authority was already
${applicationId}-relative. Launcher names come from the appLabel /
activityLabel manifestPlaceholders rather than resValue, which would
collide with Tauri's generated strings.xml; release resolves them back to
@string/app_name and merges byte-identical.

deploy-android.sh reports the target package and explains an
UPDATE_INCOMPATIBLE failure instead of leaving it raw; logcat.sh takes a
debug|release argument (it was filtering on com.jellytau.app, a package
that has never existed) and attaches by pid when the app is running.

Verified: aapt2 badging on the built APK reports
com.dtourolle.jellytau.debug / 0.5.5-debug / "JellyTau Debug", and the
release manifest merge is unchanged.

CLAUDE.md

@@ -31,6 +31,13 @@ bun run android:dev              # build + deploy
 bun run android:logs             # logcat
 ```
 
+The **debug** build type carries `applicationIdSuffix ".debug"`, so
+`com.dtourolle.jellytau.debug` ("JellyTau Debug") installs *alongside* a release
+build with its own data dir — never uninstall the release app to test a debug
+one. Only the applicationId is suffixed; Kotlin classes stay in the `namespace`
+package `com.dtourolle.jellytau`, so JNI lookups and R8 keep rules are
+unaffected. See [README_ANDROID_BUILD.md](src-tauri/android/README_ANDROID_BUILD.md).
+
 CI runs on **Gitea Actions** (`.gitea/workflows/`), not GitHub. Use the `gh` CLI
 only against the mirror if one exists; the canonical remote is
 `gitea.tourolle.paris`.

scripts/deploy-android.sh

@@ -16,10 +16,15 @@ fi
 # Build type: debug or release (default: debug)
 BUILD_TYPE="${1:-debug}"
 
+# The debug build carries applicationIdSuffix ".debug" (see
+# src-tauri/android/app/build.gradle.kts), so it is a separate package and
+# installs alongside a release build — no uninstall dance needed.
 if [ "$BUILD_TYPE" = "release" ]; then
     APK_PATH="src-tauri/gen/android/app/build/outputs/apk/universal/release/app-universal-release.apk"
+    APP_PACKAGE="com.dtourolle.jellytau"
 else
     APK_PATH="src-tauri/gen/android/app/build/outputs/apk/universal/debug/app-universal-debug.apk"
+    APP_PACKAGE="com.dtourolle.jellytau.debug"
 fi
 
 # Check if APK exists
@@ -30,8 +35,20 @@ if [ ! -f "$APK_PATH" ]; then
 fi
 
 echo "📦 Installing APK: $APK_PATH"
-adb install -r "$APK_PATH"
+echo "📛 Package: $APP_PACKAGE"
+
+if ! adb install -r "$APK_PATH"; then
+    echo ""
+    echo "❌ Install failed."
+    echo "   If it says INSTALL_FAILED_UPDATE_INCOMPATIBLE, an older build of"
+    echo "   '$APP_PACKAGE' signed with a different key is still installed."
+    echo "   Uninstall just that one and retry:"
+    echo "     adb uninstall $APP_PACKAGE"
+    exit 1
+fi
 
 echo ""
 echo "✅ Deployment complete!"
-echo "🚀 Launch the app on your device"
+echo "🚀 Launching..."
+adb shell monkey -p "$APP_PACKAGE" -c android.intent.category.LAUNCHER 1 > /dev/null 2>&1 \
+    || echo "   (auto-launch failed — start it from the launcher)"

scripts/logcat.sh

@@ -1,13 +1,34 @@
 #!/bin/bash
-# View Android logcat output filtered for the app
+# View Android logcat output filtered for the app.
+#
+# Usage: ./scripts/logcat.sh [debug|release]   (default: debug)
+#
+# The debug build has applicationIdSuffix ".debug" so it can be installed
+# alongside a release build; pick the package to follow accordingly.
 
 set -e
 
-APP_PACKAGE="com.jellytau.app"
+BUILD_TYPE="${1:-debug}"
+
+if [ "$BUILD_TYPE" = "release" ]; then
+    APP_PACKAGE="com.dtourolle.jellytau"
+else
+    APP_PACKAGE="com.dtourolle.jellytau.debug"
+fi
 
 echo "📱 Showing logcat for $APP_PACKAGE"
 echo "Press Ctrl+C to stop"
 echo ""
 
-# Filter logcat for the app's package name
-adb logcat | grep -i "$APP_PACKAGE\|tauri\|rust"
+# Prefer PID-scoped output when the app is running — it drops the noise that a
+# text grep can't. Fall back to the old keyword filter when it isn't (so you can
+# start the script first and then launch the app).
+PID="$(adb shell pidof "$APP_PACKAGE" 2>/dev/null | tr -d '\r\n' | awk '{print $1}')"
+
+if [ -n "$PID" ]; then
+    echo "   (attached to pid $PID)"
+    adb logcat --pid="$PID"
+else
+    echo "   (app not running — falling back to keyword filter)"
+    adb logcat | grep -i "$APP_PACKAGE\|jellytau\|tauri\|rust"
+fi

src-tauri/android/README_ANDROID_BUILD.md

@@ -41,6 +41,38 @@ When you need to modify Android/Kotlin files:
 - If you only edit `src-tauri/android/`, your changes won't be in the build
 - **You must edit both** (or edit source and copy to generated)
 
+### Debug and release install side by side
+
+The **debug** build type sets `applicationIdSuffix = ".debug"` in
+`app/build.gradle.kts`, so a debug build is a genuinely separate Android app:
+
+| | applicationId | launcher name | versionName |
+|---|---|---|---|
+| release | `com.dtourolle.jellytau` | jellytau | `0.5.5` |
+| debug | `com.dtourolle.jellytau.debug` | JellyTau Debug | `0.5.5-debug` |
+
+That means:
+
+- **No uninstall step.** Debug builds are signed with the local auto-generated
+  `~/.android/debug.keystore`, release builds with the real key. Two different
+  keys on the *same* package is `INSTALL_FAILED_UPDATE_INCOMPATIBLE`; two
+  different packages is just two apps.
+- Each has **its own data directory** — separate settings, credentials,
+  downloads and offline cache. A debug experiment cannot corrupt the state of
+  the build you actually use.
+- Only the *application* id changes. Kotlin classes stay in the `namespace`
+  package `com.dtourolle.jellytau`, so the JNI class lookups in
+  `src-tauri/src/player/android/mod.rs`, the manifest `<service>` entry and the
+  R8 keep rules in `proguard-jellytau.pro` are all unaffected. The FileProvider
+  authority is `${applicationId}.fileprovider`, so it follows the suffix
+  automatically.
+- The launcher labels come from the `appLabel` / `activityLabel`
+  manifestPlaceholders (`AndroidManifest.xml` uses `${appLabel}`), *not* from
+  `resValue`, which would collide with Tauri's generated `strings.xml`.
+
+Follow the right log stream with `./scripts/logcat.sh [debug|release]`
+(defaults to debug).
+
 ### Key Files
 
 Player-related Kotlin files:

src-tauri/android/app/build.gradle.kts

@@ -27,6 +27,11 @@ android {
     namespace = "com.dtourolle.jellytau"
     defaultConfig {
         manifestPlaceholders["usesCleartextTraffic"] = "false"
+        // Launcher/app names come from placeholders so the debug build can
+        // rename itself without touching the generated strings.xml (a
+        // resValue() override there would collide with Tauri's own entries).
+        manifestPlaceholders["appLabel"] = "@string/app_name"
+        manifestPlaceholders["activityLabel"] = "@string/main_activity_title"
         applicationId = "com.dtourolle.jellytau"
         minSdk = 24
         targetSdk = 36
@@ -45,6 +50,21 @@ android {
     }
     buildTypes {
         getByName("debug") {
+            // Distinct applicationId so the debug build installs SIDE BY SIDE
+            // with a release/store install instead of demanding an uninstall
+            // (different signing keys on the same package = INSTALL_FAILED_
+            // UPDATE_INCOMPATIBLE). It gets its own data dir, its own settings
+            // and its own offline cache — the two are fully independent apps.
+            //
+            // This changes only the *application* id. The Kotlin/JNI classes
+            // stay in the `namespace` package (com.dtourolle.jellytau), so the
+            // fully-qualified class names Rust looks up over JNI, the manifest
+            // <service> entry and the R8 keep rules are all unaffected. The
+            // FileProvider authority is already ${applicationId}-relative.
+            applicationIdSuffix = ".debug"
+            versionNameSuffix = "-debug"
+            manifestPlaceholders["appLabel"] = "JellyTau Debug"
+            manifestPlaceholders["activityLabel"] = "JellyTau Debug"
             manifestPlaceholders["usesCleartextTraffic"] = "true"
             isDebuggable = true
             isJniDebuggable = true

src-tauri/android/src/main/AndroidManifest.xml

@@ -11,6 +11,12 @@
   (An earlier version of this file was a partial <application> fragment on the
   assumption that Tauri merged it. It did not: the hardwareAccelerated flag it
   declared never reached any built APK. It is folded in properly below.)
+
+  ${appLabel} / ${activityLabel} are manifestPlaceholders set in
+  app/build.gradle.kts: they resolve to @string/app_name and
+  @string/main_activity_title for release, and to "JellyTau Debug" for the
+  debug build type (which also carries applicationIdSuffix ".debug" so it
+  installs alongside a release build).
 -->
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <uses-permission android:name="android.permission.INTERNET" />
@@ -26,7 +32,7 @@
 
     <application
         android:icon="@mipmap/ic_launcher"
-        android:label="@string/app_name"
+        android:label="${appLabel}"
         android:theme="@style/Theme.jellytau"
         android:hardwareAccelerated="true"
         android:networkSecurityConfig="@xml/network_security_config"
@@ -34,7 +40,7 @@
         <activity
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|smallestScreenSize|screenLayout|uiMode|density"
             android:launchMode="singleTask"
-            android:label="@string/main_activity_title"
+            android:label="${activityLabel}"
             android:name=".MainActivity"
             android:exported="true"
             android:supportsPictureInPicture="true"