When using suspend fun in Room Dao methods, following error: Not sure how to convert a Cursor to this method's return type (java.lang.Object). [236612358]

Fixed

Bug

Status Update

No update yet.

Description

ja...@gmail.com

created issue #1

Jun 21, 2022 05:30AM

Component used: Room with suspend functions i.e. coroutines

error: /Users/jayshah/AndroidStudioProjects/SampleMemoryNotes/app/build/tmp/kapt3/stubs/debug/com/example/samplememorynotes/framework/db/NoteDao.java:17: error: Not sure how to convert a Cursor to this method's return type (java.lang.Object). public abstract java.lang.Object getNoteEntity(long id, @org.jetbrains.annotations.NotNull()

Usage:

// NoteDao.kt
@Dao
interface NoteDao {

    @Insert(onConflict = REPLACE)
    suspend fun addNoteEntity(noteEntity: NoteEntity)

    @Query("select * from note where id=:id")
    suspend fun getNoteEntity(id: Long): NoteEntity

    @Query("select * from note")
    suspend fun getAllNoteEntities(): List<NoteEntity>

    @Delete
    suspend fun deleteNoteEntity(noteEntity: NoteEntity)
}

Version used:

ext.coroutines_version = "1.3.0"
ext.room_version = "2.4.2"

    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutines_version"
    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$coroutines_version"

    implementation "androidx.room:room-runtime:$room_version"
    kapt "androidx.room:room-runtime:$room_version"

    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    kapt "androidx.room:room-compiler:$room_version"
    implementation "androidx.room:room-ktx:$room_version"
    implementation "androidx.room:room-coroutines:2.1.0-alpha04"

Devices/Android versions reproduced on: Android emulator

If this is a bug in the library, we would appreciate if you could attach:

Sample project to trigger the issue: https://github.com/chetnashah/roomerrornotes
A screenrecord or screenshots showing the issue (if UI related):

Screenshot 2022-06-21 at 10.52.36 AM.png

1.4 MB

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Comments

ja...@gmail.com <ja...@gmail.com> #2Jun 21, 2022 05:43AM

+1, but Deferred does not solve the Observer problem that Rx and LiveData do, so I guess Google should implement Channels instead of LiveData which is actually a Kotlin Coroutine counterpart. Looking forward to this as I've decided not to use RxJava in most of future projects due to Kotlin Coroutines..

de...@gmail.com <de...@gmail.com> #3Jun 21, 2022 12:48PM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit e78cceffeac28f0028342990c1391c640edf453c
Author: Daniel Santiago Rivera <danysantiago@google.com>
Date: Wed Nov 28 12:40:24 2018

Room Support for Coroutines

This change allows users to define suspend functions in DAOs with
@Query, @Insert, @Update and @Delete. The new artifact room-coroutine
defines a helper classes for supporting the feature.

Bug: 69474692
Test: ./gradlew room:integration-tests:kotlintestapp:cC
Change-Id: Id73a6b845df3f21f99d14cb6980130dcf3885c81

M buildSrc/src/main/kotlin/androidx/build/PublishDocsRules.kt
A room/compiler/src/main/kotlin/androidx/room/ext/KotlinMetadataElement.kt
D room/compiler/src/main/kotlin/androidx/room/ext/KotlinMetadataProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/ext/element_ext.kt
M room/compiler/src/main/kotlin/androidx/room/ext/javapoet_ext.kt
M room/compiler/src/main/kotlin/androidx/room/processor/DeletionMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/processor/InsertionMethodProcessor.kt
A room/compiler/src/main/kotlin/androidx/room/processor/MethodProcessorDelegate.kt
M room/compiler/src/main/kotlin/androidx/room/processor/PojoProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/processor/ProcessorErrors.kt
M room/compiler/src/main/kotlin/androidx/room/processor/QueryMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/processor/RawQueryMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/processor/ShortcutMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/processor/UpdateMethodProcessor.kt
A room/compiler/src/main/kotlin/androidx/room/solver/query/result/CoroutineResultBinder.kt
M room/compiler/src/main/kotlin/androidx/room/solver/query/result/PojoRowAdapter.kt
A room/compiler/src/main/kotlin/androidx/room/solver/shortcut/binder/CoroutineDeleteOrUpdateMethodBinder.kt
A room/compiler/src/main/kotlin/androidx/room/solver/shortcut/binder/CoroutineInsertMethodBinder.kt
M room/compiler/src/main/kotlin/androidx/room/solver/shortcut/result/DeleteOrUpdateMethodAdapter.kt
M room/compiler/src/main/kotlin/androidx/room/solver/shortcut/result/InsertMethodAdapter.kt
M room/compiler/src/main/kotlin/androidx/room/vo/RelationCollector.kt
M room/compiler/src/test/kotlin/androidx/room/processor/QueryMethodProcessorTest.kt
A room/coroutines/build.gradle
A room/coroutines/src/main/AndroidManifest.xml
A room/coroutines/src/main/java/androidx/room/CoroutinesRoom.kt
M room/integration-tests/kotlintestapp/build.gradle
M room/integration-tests/kotlintestapp/src/androidTest/java/androidx/room/integration/kotlintestapp/dao/BooksDao.kt
M room/integration-tests/kotlintestapp/src/androidTest/java/androidx/room/integration/kotlintestapp/test/BooksDaoTest.kt
A room/integration-tests/kotlintestapp/src/androidTest/java/androidx/room/integration/kotlintestapp/test/SuspendRoomDispatcherTest.kt
M settings.gradle

https://android-review.googlesource.com/833705

https://goto.google.com/android-sha1/e78cceffeac28f0028342990c1391c640edf453c

de...@gmail.com <de...@gmail.com> #4Jun 21, 2022 07:46PM

So do you support any Coroutine "observables" like channels? Or these are just one-off suspending calls?

ho...@gmail.com <ho...@gmail.com> #5Jun 22, 2022 09:25AM

For now we'll be just supporting one-off suspend functions in Room 2.1.0-alpha03. Coroutines stream functionality with channels is still a work in progress.

da...@google.com <da...@google.com> #6Jun 22, 2022 03:15PM

Relating to the original request, how about allowing a return type of Deferred<LiveData<T>> which suspends until LiveData<T>'s value has been set the first time?

da...@google.com <da...@google.com> #7Jun 22, 2022 03:32PM

I just tested out Room 2.1.0-alpha03 and added suspend to all of my functions.... there appears to be an issue with functions that use @Query() and UPDATE and DELETE queries. Examples:

Code Example 1:
@Query("DELETE FROM individual")
suspend fun deleteAll()
Error:
Deletion methods must either return void or return int (the number of deleted rows).

Code Example 2:
@Query("UPDATE individual SET firstName = :firstName WHERE id = :id")
suspend fun updateFirstName(id: Long, firstName: String)
Error:
Not sure how to convert a Cursor to this method's return type (kotlin.Unit).

yy...@gmail.com <yy...@gmail.com> #8Jun 23, 2022 01:43AM

Async return types with @Query that perform UPDATE, DELETE or INSERT are not yet supported. This also applies to coroutines. We are actively working on adding this for the next alpha of 2.1.0. Subscribe to the bug for updates:

https://issuetracker.google.com/issues/120227284

ma...@gmail.com <ma...@gmail.com> #9Jun 26, 2022 12:16PM

Hello.
Any updates on returning Channel<T> from DAO?
Will contributions be accepted for that feature?

za...@gotocme.com <za...@gotocme.com> #10Jul 6, 2022 10:46AM

Channels are experimental right now so we probably want to wait until it is stable.

da...@google.com <da...@google.com> #11Jul 6, 2022 12:51PM

Channels +1

si...@gmail.com <si...@gmail.com> #12Jul 8, 2022 06:11AM

Marking as fix since core coroutines are supported in 2.1, in the mean time we'll keep an eye on the Channels API to potentially support it once its upgraded out of experimental.

https://issuetracker.google.com/issues/127328278

zs...@gmail.com <zs...@gmail.com> #13Jul 11, 2022 04:22PM

Is it expected that we still have to ensure that suspended functions aren't dispatched from the main thread?
The first call (eg `final SupportSQLiteStatement _stmt = __preparedStmtOfDeleteAll.acquire();`) is not wrapped in a callable and can't be done on the ui thread, so we still have to wrap suspensions with our own context.

da...@google.com <da...@google.com> #14Jul 11, 2022 05:17PM

Kotlinx.coroutines 1.2 released with cold stream abstraction Flow:

https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/-flow/index.html

It's in "preview" status, but maybe we also could expect some experimental version of Room with Flow support for observable requests

ge...@gmail.com <ge...@gmail.com> #15Jul 26, 2022 07:02AM

It seems to be working with Kotlin 1.7.10

da...@google.com <da...@google.com> Jul 26, 2022 12:50PM

Marked as fixed.

19...@gmail.com <19...@gmail.com> #16Oct 19, 2022 01:07AM

thanks a lot..

pi...@gmail.com <pi...@gmail.com> #17Jul 7, 2023 11:06AM

Maybe reopen this.

@Query("SELECT * FROM ${SetupData.TABLE_NAME}")
suspend fun selectAll(): Cursor

[ksp] SetupDataDao.kt:24: Not sure how to convert a Cursor to this method's return type (android.database.Cursor).

Duh!

Room 2.5.2
Kotlin 1.9
KSP 1.9.0-1.0.11

te...@gmail.com <te...@gmail.com> #18Jul 11, 2023 11:29PM

I am experiencing the same issue again with the same versions as listed above. Quite frustrating!

da...@google.com <da...@google.com> #19Jul 12, 2023 01:26PM

The diagnosis is the same, Room needs to update its kotlinx-metadata-jvm dependency to be able to read Kotlin 1.9+ metadata. An upcoming patch release (Room 2.5.3) will have the dep updated.

da...@google.com <da...@google.com> #20Jul 12, 2023 01:28PM

Alternative if you use the KSP version of Room, this shouldn't be an issue.

io...@gmail.com <io...@gmail.com> #21Jul 19, 2023 11:26AM

I can confirm that using KSP version of Room the problem with Kotlin 1.9.0 disappears

ri...@gmail.com <ri...@gmail.com> #22Aug 4, 2023 05:04AM

I solved this by upgrading the room version with 2.6.0-alpha02

bl...@gmail.com <bl...@gmail.com> #23Aug 16, 2023 11:29AM

Comment has been deleted.

Message last modified on Aug 16, 2023 11:29AM

da...@davwheat.dev <da...@davwheat.dev> #24Aug 16, 2023 11:29AM

Is there any update on when a new 2.5.x Room version might be released? This is impacting one of our products' upgrades to Kotlin 1.9, and we'd rather not depend on an alpha version.

ra...@gmail.com <ra...@gmail.com> #25Sep 5, 2023 03:11PM

Any update on release of patch version 2.5.3 which will fix above? we are stuck with kotlin 1.9.0 upgrade. Also cannot use 2.6.0-alpha/beta versions as that is compiled against sdk 34. Please help with patch asap.

ma...@gmail.com <ma...@gmail.com> #26Sep 19, 2023 09:39AM

When will be ready the new version 2.6.0? I´ve seen in 2.6.0-beta01 the issue is fixed.

sh...@navi.com <sh...@navi.com> #27Oct 13, 2023 10:15AM

When will the stable version of 2.6.0 be rolled out ?
rc has been out since 20th sept

mr...@gmail.com <mr...@gmail.com> #28Jan 5, 2024 06:29AM

I met that problem again when I use 2022.3.1 Patch 3 Android Studio, Kotlin 1.9.0, Room 2.4.1. Glad I have to see this article that is solved

pa...@gmail.com <pa...@gmail.com> #29Feb 22, 2024 07:26PM

I was facing the same issue with kotlin version - 1.9.0 and room - 2.2.5. I upgraded the room version to 2.6.1 and now it's working absolutely file. So i would suggest to anyone facing this problem to look up for the current stable release for room via this article -

https://developer.android.com/jetpack/androidx/releases/room#2.3.0-beta02 and implementing upgrading the room version accordingly.

ah...@gmail.com <ah...@gmail.com> #30Sep 12, 2024 01:00PM

Same problem here, kotlin version - 1.9.10 and room - 2.5.2
Upgraded room to version to 2.6.1 and the issue is resolved!

ni...@gmail.com <ni...@gmail.com> #31Dec 19, 2024 12:25PM

Issue is still present if you want to return Cursor

Room 2.7.0-alpha12 kotlinVersion = "2.1.0" kspVersion = "2.1.0-1.0.29"

Sample: @Query("SELECT * FROM ${SetupData.TABLE_NAME}") suspend fun selectAll(): Cursor [ksp] Not sure how to convert a Cursor to this method's return type (android.database.Cursor).

co...@gmail.com <co...@gmail.com> #32Feb 11, 2025 05:24AM

#31 thank you it is working