[Serialization] Support Compose's `MutableState` in `saved` [378895074]

Fixed

Feature

Status Update

No update yet.

Description

mg...@google.com

created issue #1

Nov 13, 2024 05:12PM

saveable has built-in support for Compose's MutableState, supporting this use case:

val state by saveable { mutableStateOf(...) }

It does this by providing an overloaded function that handles MutableState.value and serializes it when needed.

To help people migrate from saveable to saved, we want to support MutableState in our KotlinX serialization support.

While working on getMutableState, I experimented with this and created a naive KSerializer implementation to handle MutableState.

Here’s what it could look like:

private class StateSerializer<T : Any>(val valueSerializer: KSerializer<T>)

public inline fun <reified T : Any> stateSerializer(): KSerializer<MutableState<T>>

For serialization, we'd use (value as MutableState<T>).value + valueSerializer to serialize the content. Deserialization works in the opposite direction.

Here’s a usage example:

val state by saved(serializer = stateSerializer<Int>()) { mutableStateOf(1) }

However, calling this without the serializer would cause an exception.

Our variant should work like saveable: if T (the generic type in saved) is serializable, it should work without needing the serializer.

The goal is to find the best way to support MutableState in saved (using a KSerializer, overloads, or another method).

Related to b/378895070.

Comments

mg...@google.com <mg...@google.com> #2Nov 13, 2024 05:13PM

Need to bump a couple of dependencies, as well -- emoji2 and resourceinpection. Should be fine.

ap...@google.com <ap...@google.com> #3Jan 22, 2025 11:15AM

aosp/2136790 with a target release date of July 27th (yes that's the earliest release train).

ap...@google.com <ap...@google.com> #4Jan 22, 2025 11:15AM

Adding a one-off release for July 13th so we can get this out the door. Waiting on aosp/2136790 to land before we can schedule it.

mg...@google.com <mg...@google.com> Jan 22, 2025 05:34PM

Marked as fixed.

ap...@google.com <ap...@google.com> #5Jan 29, 2025 05:37PM

Bugjuggler: wait until aosp/2136790 has merged

pr...@google.com <pr...@google.com> #6Feb 12, 2025 06:40PM

Project: platform/frameworks/support
Branch: androidx-main

commit d109cf3095fe175726b4300c9985d12cf53ed18a
Author: Alan Viverette <alanv@google.com>
Date: Mon Jun 27 16:19:11 2022

Finalize AppCompat, Emoji2, and ResourceInspection APIs for beta

Pins dependencies to latest stable or RC where applicable.

Relnote: Finalize AppCompat APIs for 1.5.0-beta01
Test: ./gradlew checkApi
Bug: 236866227
Merged-In: I2a43d45452aef36c958e780c0678b2f62738b1f1
Change-Id: I2a43d45452aef36c958e780c0678b2f62738b1f1

A emoji2/emoji2/api/res-1.2.0-beta01.txt
A appcompat/appcompat-resources/api/1.5.0-beta01.txt
A emoji2/emoji2-bundled/api/public_plus_experimental_1.2.0-beta01.txt
M appcompat/appcompat/build.gradle
A emoji2/emoji2-views/api/public_plus_experimental_1.2.0-beta01.txt
A emoji2/emoji2-views/api/res-1.2.0-beta01.txt
A emoji2/emoji2-views-helper/api/1.2.0-beta01.txt
M libraryversions.toml
A emoji2/emoji2-views/api/restricted_1.2.0-beta01.txt
A emoji2/emoji2-views-helper/api/public_plus_experimental_1.2.0-beta01.txt
A emoji2/emoji2-bundled/api/1.2.0-beta01.txt
A emoji2/emoji2/api/public_plus_experimental_1.2.0-beta01.txt
A appcompat/appcompat/api/res-1.5.0-beta01.txt
A appcompat/appcompat/api/public_plus_experimental_1.5.0-beta01.txt
A emoji2/emoji2-views-helper/api/restricted_1.2.0-beta01.txt
A resourceinspection/resourceinspection-annotation/api/1.1.0-beta01.txt
A appcompat/appcompat-resources/api/public_plus_experimental_1.5.0-beta01.txt
A emoji2/emoji2-bundled/api/restricted_1.2.0-beta01.txt
A resourceinspection/resourceinspection-annotation/api/restricted_1.1.0-beta01.txt
A appcompat/appcompat-resources/api/restricted_1.5.0-beta01.txt
A emoji2/emoji2/api/1.2.0-beta01.txt
A emoji2/emoji2/api/restricted_1.2.0-beta01.txt
A emoji2/emoji2-views/api/1.2.0-beta01.txt
A emoji2/emoji2-views-helper/api/res-1.2.0-beta01.txt
A resourceinspection/resourceinspection-annotation/api/public_plus_experimental_1.1.0-beta01.txt
A appcompat/appcompat-resources/api/res-1.5.0-beta01.txt
A appcompat/appcompat/api/restricted_1.5.0-beta01.txt
A appcompat/appcompat/api/1.5.0-beta01.txt
A emoji2/emoji2-bundled/api/res-1.2.0-beta01.txt

https://android-review.googlesource.com/2136790

ap...@google.com <ap...@google.com> #7Feb 24, 2025 07:24PM

Bugjuggler: wait until 2022-07-13

ap...@google.com <ap...@google.com> #8Feb 24, 2025 07:24PM

Hi. I've received your bug and will wait until 2022-07-13 00:00 -0400 EDT and then assign the bug to alanv@google.com.

ap...@google.com <ap...@google.com> #9Feb 24, 2025 07:24PM

Remaining work:

Bump appcompat and emoji2 to rc (needs downstream merge conflict resolution CL)
Check in prebuilts for emoji2 rc for use in appcompat release branch, pin dependency
Snap release branches
Schedule releases

ap...@google.com <ap...@google.com> #10Feb 24, 2025 07:25PM

Project: platform/frameworks/support
Branch: androidx-main

commit 129b70eb3bcac9843f55489f23fcd707242b93a5
Author: Alan Viverette <alanv@google.com>
Date: Mon Jul 11 16:42:21 2022

Move appcompat and emoji2 to rc01

Moves resourceinspection back to alpha01 since we didn't release it and
don't need to bump the version. Pins our KAPT dependency to match the
library version.

Bug: 236866227
Test: ./gradlew bOS
Merged-In: If7f50424437d4847d446722978e487bf1cd0f785
Change-Id: If7f50424437d4847d446722978e487bf1cd0f785

M libraryversions.toml
D resourceinspection/resourceinspection-annotation/api/1.1.0-beta01.txt
D resourceinspection/resourceinspection-annotation/api/public_plus_experimental_1.1.0-beta01.txt
M appcompat/appcompat/build.gradle
D resourceinspection/resourceinspection-annotation/api/restricted_1.1.0-beta01.txt

https://android-review.googlesource.com/2150316

na...@google.com <na...@google.com> #11Mar 12, 2025 06:13PM

I'm going to try and shortcut the prebuilts step because it's a lot of work. Remaining:

Wait for a green build in -main
Snap release branches
Schedule releases