R8 full mode remove default constructor of androidx.lifecycle.AbstractSavedStateVMFactory$OnRecreation [132655499]

Fixed

Bug

Status Update

No update yet.

Description

yq...@gmail.com

created issue #1

May 14, 2019 06:51AM

Build Tool: com.android.tools.build:gradle:3.5.0-alpha12
androidx.lifecycle: 2.2.0-alpha01

<Steps to reproduce>
1. Based on new empty activity project, add following ViewModel class.
```
class MainViewModel(
private val savedStateHandle: SavedStateHandle
): ViewModel()
```

2. Modify MainActivity as followings.
```
class MainActivity : AppCompatActivity() {

private lateinit var viewModel: MainViewModel

override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)

viewModel = ViewModelProviders.of(
this,
SavedStateVMFactory(this)
).get(MainViewModel::class.java)
}
}
```

3. Add a keep rule for MainViewModel.
-keep class com.example.savedstateviewmodelsample.MainViewModel { *; }

4. Enable r8 fullMode and run app, then the app crash with the following error.
com.example.savedstateviewmodelsample E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.savedstateviewmodelsample, PID: 15365
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.savedstateviewmodelsample/com.example.savedstateviewmodelsample.MainActivity}: java.lang.IllegalArgumentException: ClassOnRecreation must have default constructor in order to be automatically recreated
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.IllegalArgumentException: ClassOnRecreation must have default constructor in order to be automatically recreated
at androidx.savedstate.SavedStateRegistry.runOnNextRecreation(:177)
at androidx.lifecycle.AbstractSavedStateVMFactory.create(:71)
at androidx.lifecycle.ViewModelProvider.get(:162)
at androidx.lifecycle.ViewModelProvider.get(:130)
at com.example.savedstateviewmodelsample.MainActivity.onCreate(:20)
at android.app.Activity.performCreate(Activity.java:7136)
at android.app.Activity.performCreate(Activity.java:7127)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.NoSuchMethodException: <init> []
at java.lang.Class.getConstructor0(Class.java:2327)
at java.lang.Class.getDeclaredConstructor(Class.java:2166)
at androidx.savedstate.SavedStateRegistry.runOnNextRecreation(:175)
at androidx.lifecycle.AbstractSavedStateVMFactory.create(:71)
at androidx.lifecycle.ViewModelProvider.get(:162)
at androidx.lifecycle.ViewModelProvider.get(:130)
at com.example.savedstateviewmodelsample.MainActivity.onCreate(:20)
at android.app.Activity.performCreate(Activity.java:7136)
at android.app.Activity.performCreate(Activity.java:7127)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

Comments

ch...@google.com <ch...@google.com> May 14, 2019 06:57AM

Assigned to ch...@google.com.

ch...@google.com <ch...@google.com> #2May 15, 2019 10:49AM

Looks like it's related to

https://cs.android.com/androidx/platform/frameworks/support/+/d7f5e8294c72d753234ff82e868cd09a06241c5e - When destroying the fragment view, moveToState is called and ends up re-creating the fragment view now that check has been removed

yq...@gmail.com <yq...@gmail.com> #3May 16, 2019 03:34AM

Seems like this is already fixed in master as a side effect of https://issuetracker.google.com/issues/145769287. Can you confirm this is fixed for you if you use the latest snapshot?

You'd want to add the snapshot repository to your repositories block:

maven {
  url "https://ci.android/com/builds/submitted/6080026/androidx_snapshot/latest/repository/"
}

then switch to androidx.fragment:fragment-ktx:1.3.0-SNAPSHOT.

We'll look into cherry picking the changes into Fragment 1.2.0

SavedStateViewModelSample.zip

14 MB

Download

ch...@google.com <ch...@google.com> #4May 16, 2019 07:26AM

Status: Won't Fix (Intended Behavior)

I can confirm that the issue appears to be fixed in that snapshot. Thanks!

yq...@gmail.com <yq...@gmail.com> #5May 16, 2019 09:17AM

Great, thanks for confirming.

While there isn't any specific changes needed for this issue (as the issue was already fixed before this bug was filed), I do want to explain what exactly is going to happen from a release process:

First, we'll be cherry picking in the changes needed into a Fragment 1.2.0-rc05 release (it was too late to hit rc04, which already went out earlier today). Namely, these two changes:

https://android-review.googlesource.com/1178750/
https://android-review.googlesource.com/1183079/ (this was the fix for the bug mentioned in comment#3, FWIW)

Secondly, we've added additional testing (in an unrelated, but fortuitously timed effort) specifically to cover this case to ensure this doesn't happen again in https://android-review.googlesource.com/1193030

ch...@google.com <ch...@google.com> #6May 16, 2019 09:34AM

Status: Assigned (reopened)

I could confirm the behavior on both my device and emulator. Thanks for the update and it is also good to see addition check here.

I'm curious why you need to limit the check to Build.VERSION.SDK_INT >= 17?

ch...@google.com <ch...@google.com> #7May 16, 2019 10:11AM

For the test in https://android-review.googlesource.com/1193030, isDestroyed() only exists on API 17 and higher: https://developer.android.com/reference/android/app/Activity.html#isDestroyed()

sg...@google.com <sg...@google.com> #8May 16, 2019 11:00AM

I did some digging into the androidx.lifecycle:lifecycle-viewmodel-savedstate:1.0.0-alpha01 library, and it turns out that they already supply this keep rule from the library:

-keepclassmembers,allowobfuscation class * extends androidx.savedstate.SavedStateRegistry.AutoRecreated {
<init>();
}

However, that is using the fully qualified and not the binary name of the AutoRecreated inner class.

I will create a CL, so that going forward using androidx.lifecycle:lifecycle-viewmodel-savedstate should not require additional keep rules.

sg...@google.com <sg...@google.com> #9May 20, 2019 07:31AM

Marked as fixed.

Landed the fix to androidx in

https://android-review.googlesource.com/c/platform/frameworks/support/+/963252.

Not sure when that will make it into a release.

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