add/replace using reified types cause fragments to be removed by R8 [148181315]

Fixed

Bug

Status Update

No update yet.

Description

my...@gmail.com

created issue #1

Jan 23, 2020 01:49AM

Component used: Fragment
Version used: 1.2.0
Devices/Android versions reproduced on: N/A

Fragment constructor is removed once we use add/replace<MyFragment>(...).

Comments

il...@google.com <il...@google.com> #2Jan 23, 2020 05:27PM

Yigit, do you have time to fix it?

reemission of the same liveData is racy

my...@gmail.com <my...@gmail.com> #3Jan 23, 2020 06:02PM

yea i'll take it.

my...@gmail.com <my...@gmail.com> #4Jan 23, 2020 06:03PM

Thanks for the detailed analysis. This may not be an issue anymore since we've started using Main.immediate there but I' not sure; I'll try to create a test case.

il...@google.com <il...@google.com> #5Jan 23, 2020 09:14PM

Assigned to il...@google.com.

just emitting same live data reproduces the issue.

@Test
fun raceTest() {
val subLiveData = MutableLiveData(1)
val subject = liveData(testScope.coroutineContext) {
emitSource(subLiveData)
emitSource(subLiveData) //crashes
}
subject.addObserver().apply {
testScope.advanceUntilIdle()
}
}

il...@google.com <il...@google.com> Jan 23, 2020 10:24PM

Accepted by il...@google.com.

ap...@google.com <ap...@google.com> #6Jan 23, 2020 10:56PM

With 2.2.0-alpha04 (that use Main.immediate), the issue seems to be still there (I tested it by calling emitSource() twice, like your test case)

il...@google.com <il...@google.com> #7Jan 23, 2020 10:57PM

Marked as fixed.

yea sorry immediate does not fix it.
I actually have a WIP fix for it:

https://android-review.googlesource.com/c/platform/frameworks/support/+/1112186

if your case is the one i found (emitting same LiveData multiple times, as shown in #5) you can work around it by adding a dummy transformation.

val subLiveData = MutableLiveData(1)
val subject = liveData(testScope.coroutineContext) {
emitSource(subLiveData.map {it })
emitSource(subLiveData.map {it} )
}

an...@google.com <an...@google.com> #8Jan 23, 2020 11:06PM

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

commit af12e75e6b4110f48e44ca121466943909de8f06
Author: Yigit Boyar <yboyar@google.com>
Date: Tue Sep 03 12:58:11 2019

Fix coroutine livedata race condition

This CL fixes a bug in liveData builder where emitting same
LiveData source twice would make it crash because the second
emission registry could possibly happen before first one is
removed as source.

We fix it by using a suspending dispose function. It does feel
a bit hacky but we cannot make DisposableHandle.dispose async
and we do not want to block there. This does not mean that there
is a problem if developer disposes it manually since our emit
functions take care of making sure it disposes (and there is
no other way to add source to the underlying MediatorLiveData)

Bug: 140249349
Test: BuildLiveDataTest#raceTest_*

Change-Id: I0b464c242a583da4669af195cf2504e2adc4de40

M lifecycle/lifecycle-livedata-ktx/api/2.2.0-alpha05.txt
M lifecycle/lifecycle-livedata-ktx/api/current.txt
M lifecycle/lifecycle-livedata-ktx/api/public_plus_experimental_2.2.0-alpha05.txt
M lifecycle/lifecycle-livedata-ktx/api/public_plus_experimental_current.txt
M lifecycle/lifecycle-livedata-ktx/api/restricted_2.2.0-alpha05.txt
M lifecycle/lifecycle-livedata-ktx/api/restricted_current.txt
M lifecycle/lifecycle-livedata-ktx/src/main/java/androidx/lifecycle/CoroutineLiveData.kt
M lifecycle/lifecycle-livedata-ktx/src/test/java/androidx/lifecycle/BuildLiveDataTest.kt

https://android-review.googlesource.com/1112186

https://goto.google.com/android-sha1/af12e75e6b4110f48e44ca121466943909de8f06

[Deleted User] <[Deleted User]> #9Mar 19, 2020 03:03PM

Just wanted to add that clicking on file fragment/fragment/proguard-rules.pro in the comment #6, which is highlighted (like a link) redirect the user to a scam web page.

You should remove those redirects when the tool post the patch details here. I would not expect that clicking (like I did) on a file-patch link as a chance to infect my PC with some malwares.

Thank you.

[Deleted User] <[Deleted User]> #10Mar 19, 2020 03:09PM

This is a security problem. Every link on the page is not a direct link but a google search with redirect, in this particular case there is a registered scam domain with proguard-rules.pr0 (used 0 to prevent link instead of o)

an...@google.com <an...@google.com> #11Mar 24, 2020 12:10AM

The following changes were cherrypicked through Coastguard (

https://android-build.googleplex.com/coastguard/)
Release Track: (

https://android-build.googleplex.com/coastguard/dashboard/6552735953321984/#/history/all)
Created: 2020-03-24 00:08:58.917870+00:00
Changes: aosp/1266484

ap...@google.com <ap...@google.com> #12Mar 24, 2020 04:53AM

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

commit 41c9e54ce4ab51f95d19a55fa92a56b6bd018c62
Author: Ian Lake <ilake@google.com>
Date: Mon Mar 23 16:07:32 2020

Allow obfuscation of kept Fragments

Fragments that are kept solely by class
can safely be obfuscated.

By switching to keepclasseswithmembers,
only classes with a default constructor
will qualify to be kept. This also allows
shrinking of classes that are constructed
through a custom FragmentFactory.

Test: tested in sample app at

bug 148181315

#comment4
BUG: 151605338
Change-Id: I68ea8779bce80f33f27658cf87a94ccede5376b0

M fragment/fragment/proguard-rules.pro

https://android-review.googlesource.com/1266484