Serialize demo SQL and block concurrent taps

Author: 0xadam-brown

sentry-samples/sentry-samples-android/src/main/java/io/sentry/samples/android/sqlite/SQLiteActivity.kt

@@ -353,6 +353,8 @@ class SQLiteActivity : ComponentActivity() {
 
   /** Run the variant's SQL statement inside a manual, scope-bound transaction. */
   private fun onTap(variant: DemoVariant) {
+    if (dbOperationInFlight) return
+
     sqlDetail = if (heavyWork) variant.displayInfo.sqlHeavy else variant.displayInfo.sql
     runTick++ // shimmer the detail box outline in the integration color
 
@@ -376,6 +378,8 @@ class SQLiteActivity : ComponentActivity() {
    * `ui.load` transaction owns the spans.
    */
   private fun onLongPress(variant: DemoVariant) {
+    if (dbOperationInFlight) return
+
     sqlDetail = if (heavyWork) variant.displayInfo.sqlHeavy else variant.displayInfo.sql
     latestResult = "Opened the auto-load screen — its ui.load transaction owns the db spans."
     startActivity(UiLoadActivity.intent(this, variant.demo, heavyWork))
@@ -598,7 +602,7 @@ class SQLiteActivity : ComponentActivity() {
   }
 
   /** Closes + deletes every demo database file (via [SampleDatabases]), then re-warms them. */
-  private fun resetDatabases(): String {
+  private suspend fun resetDatabases(): String {
     val cleared = SampleDatabases.reset(applicationContext)
     return "Dropped tables: cleared $cleared database file(s)."
   }

sentry-samples/sentry-samples-android/src/main/java/io/sentry/samples/android/sqlite/SampleDatabases.kt

@@ -19,6 +19,8 @@ import io.sentry.sqlite.SentrySQLiteDriver
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 
 /**
  * Process-lifetime holder for the demo databases used by [SQLiteActivity].
@@ -40,9 +42,14 @@ import kotlinx.coroutines.launch
  */
 object SampleDatabases {
 
+  private val sqlAccess = Mutex()
+
   val driverDirectLock = Any()
   val openHelperDirectLock = Any()
 
+  /** Serializes demo SQL and [reset] so handles are never closed mid-statement. */
+  suspend fun <T> withSqlAccess(block: suspend () -> T): T = sqlAccess.withLock { block() }
+
   @Volatile private var driverConnection: SQLiteConnection? = null
   @Volatile private var driverRoom2Db: SampleRoom2Database? = null
   @Volatile private var driverRoom3Db: SampleRoom3Database? = null
@@ -170,9 +177,9 @@ object SampleDatabases {
 
   /**
    * Closes the open handles, deletes every demo database file, then re-warms. Returns the number of
-   * files cleared.
+   * files cleared. Waits for any in-flight demo SQL (including [UiLoadActivity]) to finish first.
    */
-  fun reset(context: Context): Int {
+  suspend fun reset(context: Context): Int = withSqlAccess {
     closeAll()
     val appContext = context.applicationContext
     val names =
@@ -186,7 +193,7 @@ object SampleDatabases {
       )
     val cleared = names.count { appContext.deleteDatabase(it) }
     warmUp(appContext)
-    return cleared
+    cleared
   }
 
   private fun closeAll() {

sentry-samples/sentry-samples-android/src/main/java/io/sentry/samples/android/sqlite/SqlStatements.kt

@@ -59,13 +59,15 @@ object SqlStatements {
     Array(rowCount * 2) { i -> if (i % 2 == 0) "song ${i / 2}" else "artist ${i / 2}" }
 
   suspend fun execute(context: Context, demo: SqlDemo, heavy: Boolean): String =
-    when (demo) {
-      SqlDemo.DRIVER_DIRECT -> driverDirect(context, heavy)
-      SqlDemo.DRIVER_ROOM2 -> driverWithRoom2(context, heavy)
-      SqlDemo.DRIVER_ROOM3 -> driverWithRoom3(context, heavy)
-      SqlDemo.OPENHELPER_DIRECT -> openHelperDirect(context, heavy)
-      SqlDemo.OPENHELPER_ROOM -> openHelperWithRoom(context, heavy)
-      SqlDemo.OPENHELPER_SQLDELIGHT -> openHelperWithSqlDelight(context, heavy)
+    SampleDatabases.withSqlAccess {
+      when (demo) {
+        SqlDemo.DRIVER_DIRECT -> driverDirect(context, heavy)
+        SqlDemo.DRIVER_ROOM2 -> driverWithRoom2(context, heavy)
+        SqlDemo.DRIVER_ROOM3 -> driverWithRoom3(context, heavy)
+        SqlDemo.OPENHELPER_DIRECT -> openHelperDirect(context, heavy)
+        SqlDemo.OPENHELPER_ROOM -> openHelperWithRoom(context, heavy)
+        SqlDemo.OPENHELPER_SQLDELIGHT -> openHelperWithSqlDelight(context, heavy)
+      }
     }
 
   // --- 1. SentrySQLiteDriver, used directly -------------------------------------------------