Show error toast if empty URI is passed when trying to create/restore a backup

app/src/main/java/eu/kanade/tachiyomi/data/backup/AbstractBackupManager.kt

@@ -21,7 +21,7 @@ abstract class AbstractBackupManager(protected val context: Context) {
     internal val trackManager: TrackManager by injectLazy()
     protected val preferences: PreferencesHelper by injectLazy()
 
-    abstract fun createBackup(uri: Uri, flags: Int, isJob: Boolean): String?
+    abstract fun createBackup(uri: Uri, flags: Int, isJob: Boolean): String
 
     /**
      * Returns manga

app/src/main/java/eu/kanade/tachiyomi/data/backup/full/FullBackupManager.kt

@@ -44,7 +44,7 @@ class FullBackupManager(context: Context) : AbstractBackupManager(context) {
      * @param uri path of Uri
      * @param isJob backup called from job
      */
-    override fun createBackup(uri: Uri, flags: Int, isJob: Boolean): String? {
+    override fun createBackup(uri: Uri, flags: Int, isJob: Boolean): String {
         // Create root object
         var backup: Backup? = null
 
@@ -87,7 +87,7 @@ class FullBackupManager(context: Context) : AbstractBackupManager(context) {
             file.openOutputStream().sink().gzip().buffer().use { it.write(byteArray) }
             val fileUri = file.uri
 
-            // Validate it to make sure it works
+            // Make sure it's a valid backup file
             FullBackupRestoreValidator().validate(context, fileUri)
 
             return fileUri.toString()

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsBackupController.kt

@@ -162,39 +162,33 @@ class SettingsBackupController : SettingsController() {
             val activity = activity ?: return
             val uri = data.data
 
+            if (uri == null) {
+                activity.toast(R.string.backup_restore_invalid_uri)
+                return
+            }
+
             when (requestCode) {
                 CODE_BACKUP_DIR -> {
                     // Get UriPermission so it's possible to write files
                     val flags = Intent.FLAG_GRANT_READ_URI_PERMISSION or
                         Intent.FLAG_GRANT_WRITE_URI_PERMISSION
 
-                    if (uri != null) {
-                        activity.contentResolver.takePersistableUriPermission(uri, flags)
-                    }
-
-                    // Set backup Uri
+                    activity.contentResolver.takePersistableUriPermission(uri, flags)
                     preferences.backupsDirectory().set(uri.toString())
                 }
                 CODE_BACKUP_CREATE -> {
                     val flags = Intent.FLAG_GRANT_READ_URI_PERMISSION or
                         Intent.FLAG_GRANT_WRITE_URI_PERMISSION
 
-                    if (uri != null) {
-                        activity.contentResolver.takePersistableUriPermission(uri, flags)
-                    }
-
-                    val file = UniFile.fromUri(activity, uri)
-
-                    activity.toast(R.string.creating_backup)
-
+                    activity.contentResolver.takePersistableUriPermission(uri, flags)
                     BackupCreateService.start(
                         activity,
-                        file.uri,
+                        uri,
                         backupFlags,
                     )
                 }
                 CODE_BACKUP_RESTORE -> {
-                    uri?.let { RestoreBackupDialog(it).showDialog(router) }
+                    RestoreBackupDialog(uri).showDialog(router)
                 }
             }
         }

app/src/main/res/values/strings.xml

@@ -425,6 +425,7 @@
     <string name="pref_backup_slots">Maximum backups</string>
     <string name="source_not_found_name">Source not found: %1$s</string>
     <string name="tracker_not_logged_in">Not logged in: %1$s</string>
+    <string name="backup_restore_invalid_uri">Error: empty URI</string>
     <string name="backup_created">Backup created</string>
     <string name="invalid_backup_file">Invalid backup file</string>
     <string name="invalid_backup_file_missing_data">File is missing data.</string>