new: enable StrictMode in debug builds

androidApp/README.md

@@ -5,6 +5,21 @@
 GlitchTip is configured in the project. It uses the open source solution Senstry to log crashes
 generated by the app and send them to GlitchTip on a European server.
 
+## StrictMode (debug builds)
+
+The app enables Android [StrictMode](https://developer.android.com/reference/android/os/StrictMode)
+**only for debuggable builds** (gated on debug versions, so release builds are never affected).
+
+Both the thread policy (disk/network on the main thread, etc.) and the VM policy (leaked
+`Closeable`s, activity leaks, etc.) are enabled and logged to Logcat.
+
+To see violations, filter Logcat for the `StrictMode` tag while running a debug build:
+
+```bash
+./gradlew :androidApp:installDebug
+adb logcat -s StrictMode
+```
+
 ## Signing
 
 Release builds of the Android app are signed with a keystore whose credentials

androidApp/src/main/kotlin/bzh/ajaury/chombev/ChomBevApp.kt

@@ -1,5 +1,39 @@
 package bzh.ajaury.chombev
 
 import android.app.Application
+import android.content.pm.ApplicationInfo
+import android.os.StrictMode
 
-class ChomBevApp : Application()
+class ChomBevApp : Application() {
+    override fun onCreate() {
+        super.onCreate()
+        if (isDebuggable()) {
+            enableStrictMode()
+        }
+    }
+
+    private fun isDebuggable(): Boolean =
+        applicationInfo.flags and ApplicationInfo.FLAG_DEBUGGABLE != 0
+
+    /**
+     * Enables StrictMode for debug builds only. All violations are logged
+     * ([StrictMode.ThreadPolicy.Builder.penaltyLog]) so problems surface in Logcat
+     * without ever crashing the app (no `penaltyDeath`).
+     */
+    private fun enableStrictMode() {
+        StrictMode.setThreadPolicy(
+            StrictMode.ThreadPolicy
+                .Builder()
+                .detectAll()
+                .penaltyLog()
+                .build(),
+        )
+        StrictMode.setVmPolicy(
+            StrictMode.VmPolicy
+                .Builder()
+                .detectAll()
+                .penaltyLog()
+                .build(),
+        )
+    }
+}