Preserve home screen data when grid migration fails

DEVDOC.md

@@ -1,3 +1,19 @@
+## Local migration regression tests
+
+With JDK 21 and the Android SDK configured (`ANDROID_HOME` or `local.properties`), run:
+
+```sh
+./gradlew testAospOmegaDebugUnitTest --tests '*GridSizeMigrationRegressionTest'
+```
+
+These tests live in `tests/unit/src`, outside the production `src` source root. They use
+Robolectric API 35 and native, file-backed SQLite with the production migration/controller
+implementation. Coverage includes SQLite rollback, retry/reopen, widget and folder preservation,
+fresh database initialization, invalid/no-op migrations, and loader cancellation before defaults,
+cleanup, binding, or loader-transaction commit. Application DI, logging, and the smartspace setting
+are mocked; no device or launcher application startup is required. This suite does not replace
+the existing device/Soong tests under `tests/src`.
+
 ## Development Progress
 
 - [ ] Rebase on A13

build.gradle.kts

@@ -184,6 +184,10 @@ extensions.configure<ApplicationExtension> {
     }
 
     sourceSets {
+        named("test") {
+            java.directories.add("tests/unit/src")
+            kotlin.directories.add("tests/unit/src")
+        }
         named("main") {
             java.directories.addAll(
                 listOf(
@@ -229,6 +233,15 @@ extensions.configure<ApplicationExtension> {
         checkReleaseBuilds = false
         disable += listOf("MissingTranslation", "ExtraTranslation")
     }
+
+    testOptions {
+        unitTests.isIncludeAndroidResources = true
+        unitTests.all {
+            val scratchDir = layout.buildDirectory.dir("unitTestScratch").get().asFile
+            it.systemProperty("java.io.tmpdir", scratchDir.absolutePath)
+            it.doFirst { scratchDir.mkdirs() }
+        }
+    }
 }
 protobuf {
     protoc {
@@ -356,6 +369,8 @@ dependencies {
     protobuf(files("protos_overrides/"))
 
     testImplementation(libs.junit)
+    testImplementation(libs.mockito.core)
+    testImplementation(libs.robolectric)
     androidTestImplementation(libs.dexmaker.mockito)
     androidTestImplementation(libs.junit.jupiter)
     androidTestImplementation(libs.mockito.core)

gradle/libs.versions.toml

@@ -51,6 +51,7 @@ junit = "4.13.2"
 junit5 = "6.1.1"
 truth = "1.4.5"
 mockito = "5.23.0"
+robolectric = "4.16.1"
 dexmaker = "1.2"
 androidx-annotation = "1.10.0"
 androidx-test = "1.3.0"
@@ -137,6 +138,7 @@ dexmaker-mockito = { module = "com.google.dexmaker:dexmaker-mockito", version.re
 junit = { module = "junit:junit", version.ref = "junit" }
 junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit5" }
 mockito-core = { module = "org.mockito:mockito-core", version.ref = "mockito" }
+robolectric = { module = "org.robolectric:robolectric", version.ref = "robolectric" }
 runner = { module = "com.android.support.test:runner", version.ref = "support-runner" }
 rules = { module = "com.android.support.test:rules", version.ref = "support-rules" }
 test-junit = { module = "androidx.test.ext:junit", version.ref = "androidx-test" }

res/values/strings.xml

@@ -257,6 +257,9 @@
     <string name="permdesc_write_settings">Allows the app to change the settings and
         shortcuts in home.</string>
 
+    <!-- Shown when a grid migration fails and loading stops to preserve the saved layout. -->
+    <string name="workspace_migration_failed">Couldn\'t migrate the home screen. Your saved layout has not been reset.</string>
+
     <!-- Widgets: -->
     <skip />
 

src/com/android/launcher3/model/GridSizeMigrationDBController.kt

@@ -115,8 +115,8 @@ object GridSizeMigrationDBController {
         idsInUse: List<Int>,
     ): Int {
         var newId = -1
-        val c =
-            helper.writableDatabase.query(
+        helper.writableDatabase
+            .query(
                 srcTableName,
                 null,
                 LauncherSettings.Favorites._ID + " = '" + (entry?.id ?: id) + "'",
@@ -125,18 +125,20 @@ object GridSizeMigrationDBController {
                 null,
                 null,
             )
-        while (c.moveToNext()) {
-            val values = ContentValues()
-            DatabaseUtils.cursorRowToContentValues(c, values)
-            entry?.updateContentValues(values)
-                ?: values.put(LauncherSettings.Favorites.CONTAINER, folderId)
-            do {
-                newId = helper.generateNewItemId()
-            } while (idsInUse.contains(newId))
-            values.put(LauncherSettings.Favorites._ID, newId)
-            helper.writableDatabase.insert(destTableName, null, values)
-        }
-        c.close()
+            .use { c ->
+                check(c.moveToFirst()) {
+                    "Missing migration entry ${entry?.id ?: id} in $srcTableName"
+                }
+                val values = ContentValues()
+                DatabaseUtils.cursorRowToContentValues(c, values)
+                entry?.updateContentValues(values)
+                    ?: values.put(LauncherSettings.Favorites.CONTAINER, folderId)
+                do {
+                    newId = helper.generateNewItemId()
+                } while (idsInUse.contains(newId))
+                values.put(LauncherSettings.Favorites._ID, newId)
+                helper.writableDatabase.insertOrThrow(destTableName, null, values)
+            }
         return newId
     }
 

src/com/android/launcher3/model/GridSizeMigrationLogic.kt

@@ -67,7 +67,6 @@ constructor(
         target: DatabaseHelper,
         source: SQLiteDatabase,
         isDestNewDb: Boolean,
-        modelDelegate: ModelDelegate,
     ) {
 
         if (!GridSizeMigrationDBController.needsToMigrate(srcDeviceState, destDeviceState)) {
@@ -82,86 +81,70 @@ constructor(
                 "$srcDeviceState\ndestDeviceState: $destDeviceState\nisDestNewDb: $isDestNewDb",
         )
 
-        val shouldMigrateToStrtictlyTallerGrid =
+        val shouldMigrateToStrictlyTallerGrid =
             shouldMigrateToStrictlyTallerGrid(isDestNewDb, srcDeviceState, destDeviceState)
-        if (shouldMigrateToStrtictlyTallerGrid) {
-            copyTable(source, TABLE_NAME, target.writableDatabase, TABLE_NAME, context)
-        } else {
-            copyTable(source, TABLE_NAME, target.writableDatabase, TMP_TABLE, context)
-        }
+        // Stage the source before the transaction: copyTable attaches and detaches its database.
+        // Never replace favorites outside the transaction, even for the taller-grid shortcut.
+        copyTable(source, TABLE_NAME, target.writableDatabase, TMP_TABLE, context)
 
         val migrationStartTime = System.currentTimeMillis()
         try {
             SQLiteTransaction(target.writableDatabase).use { t ->
                 // We want to add the extra row(s) to the top of the screen, so we shift the grid
                 // down.
-                if (shouldMigrateToStrtictlyTallerGrid) {
+                if (shouldMigrateToStrictlyTallerGrid) {
                     Log.d(TAG, "Migrating to strictly taller grid")
+                    copyTable(t.db, TMP_TABLE, t.db, TABLE_NAME, context)
                     if (Flags.oneGridSpecs()) {
                         shiftWorkspaceByXCells(
                             target.writableDatabase,
                             (destDeviceState.rows - srcDeviceState.rows),
                             TABLE_NAME,
                         )
                     }
-                    // Save current configuration, so that the migration does not run again.
-                    destDeviceState.writeToPrefs(context)
-                    t.commit()
-
-                    if (isOneGridMigration(srcDeviceState, destDeviceState)) {
-                        statsLogManager.logger().log(LAUNCHER_ROW_SHIFT_ONE_GRID_MIGRATION)
-                    }
-                    statsLogManager.logger().log(LAUNCHER_ROW_SHIFT_GRID_MIGRATION)
-
-                    return
+                } else {
+                    val srcReader = DbReader(t.db, TMP_TABLE, context)
+                    val destReader = DbReader(t.db, TABLE_NAME, context)
+
+                    val targetSize = Point(destDeviceState.columns, destDeviceState.rows)
+
+                    // Keep destination IDs so newly added items cannot collide with them.
+                    val idsInUse = mutableListOf<Int>()
+
+                    migrateHotseat(
+                        srcDeviceState.numHotseat,
+                        destDeviceState.numHotseat,
+                        srcReader,
+                        destReader,
+                        target,
+                        idsInUse,
+                    )
+                    migrateWorkspace(srcReader, destReader, target, targetSize, idsInUse)
                 }
 
-                val srcReader = DbReader(t.db, TMP_TABLE, context)
-                val destReader = DbReader(t.db, TABLE_NAME, context)
-
-                val targetSize = Point(destDeviceState.columns, destDeviceState.rows)
-
-                // Here we keep all the DB ids we have in the destination DB such that we don't
-                // assign
-                // an item that we want to add to the destination DB the same id as an already
-                // existing
-                // item.
-                val idsInUse = mutableListOf<Int>()
-
-                // Migrate hotseat.
-                migrateHotseat(
-                    srcDeviceState.numHotseat,
-                    destDeviceState.numHotseat,
-                    srcReader,
-                    destReader,
-                    target,
-                    idsInUse,
-                )
-                // Migrate workspace.
-                migrateWorkspace(srcReader, destReader, target, targetSize, idsInUse)
-
                 dropTable(t.db, TMP_TABLE)
                 t.commit()
-
-                if (isOneGridMigration(srcDeviceState, destDeviceState)) {
-                    statsLogManager.logger().log(LAUNCHER_STANDARD_ONE_GRID_MIGRATION)
-                }
-                statsLogManager.logger().log(LAUNCHER_STANDARD_GRID_MIGRATION)
             }
         } catch (e: Exception) {
             FileLog.e(TAG, "Error during grid migration", e)
-        } finally {
-            Log.v(
-                TAG,
-                "Workspace migration completed in " +
-                    (System.currentTimeMillis() - migrationStartTime),
-            )
-
-            // Save current configuration, so that the migration does not run again.
-            destDeviceState.writeToPrefs(context)
+            throw e
+        }
 
-            // Notify if we've migrated successfully
-            modelDelegate.gridMigrationComplete(srcDeviceState, destDeviceState)
+        Log.v(
+            TAG,
+            "Workspace migration completed in " +
+                (System.currentTimeMillis() - migrationStartTime),
+        )
+        if (shouldMigrateToStrictlyTallerGrid) {
+            if (isOneGridMigration(srcDeviceState, destDeviceState)) {
+                statsLogManager.logger().log(LAUNCHER_ROW_SHIFT_ONE_GRID_MIGRATION)
+            }
+            statsLogManager.logger().log(LAUNCHER_ROW_SHIFT_GRID_MIGRATION)
+        } else {
+            if (isOneGridMigration(srcDeviceState, destDeviceState)) {
+                statsLogManager.logger().log(LAUNCHER_STANDARD_ONE_GRID_MIGRATION)
+            }
+            statsLogManager.logger().log(LAUNCHER_STANDARD_GRID_MIGRATION)
         }
     }
 

src/com/android/launcher3/model/LoaderTask.java

@@ -29,6 +29,7 @@
 import static com.android.launcher3.model.data.AppsListData.FLAG_QUIET_MODE_ENABLED;
 import static com.android.launcher3.model.data.AppsListData.FLAG_WORK_PROFILE_QUIET_MODE_ENABLED;
 import static com.android.launcher3.model.data.ItemInfoWithIcon.FLAG_INSTALL_SESSION_ACTIVE;
+import static com.android.launcher3.util.Executors.MAIN_EXECUTOR;
 import static com.android.launcher3.util.Executors.MODEL_EXECUTOR;
 import static com.android.launcher3.util.LooperExecutor.CALLER_LOADER_TASK;
 import static com.android.launcher3.util.PackageManagerHelper.hasShortcutsPermission;
@@ -48,6 +49,7 @@
 import android.os.UserHandle;
 import android.util.Log;
 import android.util.LongSparseArray;
+import android.widget.Toast;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -58,6 +60,7 @@
 import com.android.launcher3.InvariantDeviceProfile;
 import com.android.launcher3.LauncherModel;
 import com.android.launcher3.LauncherPrefs;
+import com.android.launcher3.R;
 import com.android.launcher3.Utilities;
 import com.android.launcher3.backuprestore.LauncherRestoreEventLogger;
 import com.android.launcher3.dagger.ApplicationContext;
@@ -450,6 +453,12 @@ private void loadWorkspaceImpl(
             dbController.attemptMigrateDb(restoreEventLogger, mModelDelegate);
         } catch (Exception e) {
             FileLog.e(TAG, "Failed to migrate grid", e);
+            MAIN_EXECUTOR.execute(() -> Toast.makeText(
+                    mContext, R.string.workspace_migration_failed, Toast.LENGTH_LONG).show());
+            CancellationException cancelled =
+                    new CancellationException("Workspace loading cancelled after migration failure");
+            cancelled.initCause(e);
+            throw cancelled;
         }
 
         Log.d(TAG, "loadWorkspace: loading default favorites if necessary");