android/core/preferences/src/main/kotlin/com/flagship/abox/manager/preferences/DataStoreUiPreferencesRepository.kt

@@ -38,9 +38,16 @@ class DataStoreUiPreferencesRepository internal constructor(
         transform: (UiPreferences) -> UiPreferences,
     ): UiPreferencesWriteResult = try {
         dataStore.edit { storedPreferences ->
-            storedPreferences.putAll(transform(preferencesFrom(storedPreferences)))
+            val updatedPreferences = try {
+                transform(preferencesFrom(storedPreferences))
+            } catch (cause: Throwable) {
+                throw TransformFailure(cause)
+            }
+            storedPreferences.putAll(updatedPreferences)
         }
         UiPreferencesWriteResult.Success
+    } catch (failure: TransformFailure) {
+        throw failure.cause
     } catch (cause: CancellationException) {
         throw cause
     } catch (_: IOException) {
@@ -71,6 +78,10 @@ class DataStoreUiPreferencesRepository internal constructor(
     private inline fun <reified T : Enum<T>> String.enumOrDefault(default: T): T =
         enumValues<T>().firstOrNull { it.name == this } ?: default
 
+    private class TransformFailure(
+        override val cause: Throwable,
+    ) : RuntimeException(cause)
+
     private companion object {
         val RENDERER = stringPreferencesKey("renderer")
         val THEME_MODE = stringPreferencesKey("theme_mode")

android/core/preferences/src/test/kotlin/com/flagship/abox/manager/preferences/DataStoreUiPreferencesRepositoryTest.kt

@@ -99,6 +99,18 @@ class DataStoreUiPreferencesRepositoryTest {
         assertEquals(failure, actual)
     }
 
+    @Test
+    fun updateRethrowsTransformIOException() = runTest {
+        val repository = DataStoreUiPreferencesRepository(InMemoryPreferencesDataStore())
+        val failure = IOException("invalid transform")
+
+        val actual = runCatching {
+            repository.update { throw failure }
+        }.exceptionOrNull()
+
+        assertEquals(failure, actual)
+    }
+
     @Test
     fun updateRethrowsCancellationException() = runTest {
         val cancellation = CancellationException("cancelled")