DataSource.Factory with map/mapByPage does not invalidate source in Paging 3 [165313046]

Fixed

Bug

Status Update

No update yet.

Description

ti...@chainels.com

created issue #1

Aug 18, 2020 07:13PM

Component used: Paging
Version used: 3.0 alpha-04
Devices/Android versions reproduced on: n/a

Today (after many hours of debugging) I seem to have found a bug in latest alpha version of the Paging library. In my app I still have various lists that are not yet migrated to the new v3 API's, but since the documentation states it's backward compatible I figured that was okay.

Those lists use the database + remote pattern. One such list displayed strange behavior, it seemed to call all the boundary callbacks correctly, do the API call, and insert the new items in the database, however the items in the RecyclerView did not change.

The only difference that I could find between that list and other lists that were functioning correctly, is that it used a map function on the Datasource.Factory returned by Room

I think I found the underlying issue. The data source does not seem to be invalidated when using a map function.

DataSource has two variants of addOnValidationCallback. An open function DataSource.kt:366 and a final function that accepts Kotlin functions DataSource.kt:385

The Kotlin version is actually called in LegacyPagingSource

However when using a map/mapByPage function on the factory returned by room, the source is wrapped and in that class (WrappedDataSource, but also WrapperPositionalDataSource for example) only the non Kotlin version of addOnValidationCallback is overridden, and thus if called with the Kotlin version, addOnValidationCallback is never called on the source of the wrapper.

I could see when debugging that indeed onInvalidatedCallbacks is empty.

Hopefully this is actually the cause of the behavior I'm seeing. The Paging code is quite complex so I could be missing something else.

Comments

du...@google.com <du...@google.com> #2Aug 19, 2020 05:12PM

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

commit b90079595f33f58fece04026a97faa0d243acdb1
Author: Yuichi Araki <yaraki@google.com>
Date: Wed Sep 18 16:55:49 2019

Change the way to detect mismatch between POJO and query

This fixes cursor mismatch warnings with expandProjection.

Bug: 140759491
Test: QueryMethodProcessorTest
Change-Id: I7659002e5e0d1ef60fc1af2a625c0c36da0664d8

M room/compiler/src/main/kotlin/androidx/room/processor/QueryMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/solver/TypeAdapterStore.kt
M room/compiler/src/main/kotlin/androidx/room/solver/query/result/PojoRowAdapter.kt
M room/compiler/src/test/kotlin/androidx/room/processor/QueryMethodProcessorTest.kt
M room/compiler/src/test/kotlin/androidx/room/testing/TestProcessor.kt

https://android-review.googlesource.com/1123258

https://goto.google.com/android-sha1/b90079595f33f58fece04026a97faa0d243acdb1

du...@google.com <du...@google.com> #3Sep 4, 2020 03:28AM

Accepted by du...@google.com.

The following changes were cherrypicked through Coastguard (

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

https://android-build.googleplex.com/coastguard/dashboard/6093116828680192/#/cherrypickHistory/all)
Created: 2019-10-14 17:23:42.610596+00:00
Changes: aosp/1123258

ti...@chainels.com <ti...@chainels.com> #4Sep 4, 2020 12:25PM

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

commit bdde5a1a970ddc9007b28de4aa29d60ffa588f08
Author: Yigit Boyar <yboyar@google.com>
Date: Thu Apr 16 16:47:05 2020

Re-factor how errors are dismissed when query is re-written

This CL changes how we handle errors/warnings if query is
re-written.
There was a bug in expandProjection where we would report warnings
for things that Room already fixes automatically (

b/140759491

).
The solution to that problem (I7659002e5e0d1ef60fc1af2a625c0c36da0664d8)
solved it by deferring validating of columns until after re-write
decision is made. Unfortunately, this required changing PojoRowAdapter
to have a dummy mapping until it is validating, make it hard to use
as it does have a non-null mapping which is not useful.

This CL partially reverts that change and instead rely on the log
deferring logic we have in Context. This way, we don't need to break
the stability of PojoRowAdapter while still having the ability to
drop warnings that room fixes. This will also play nicer when we
have different query re-writing options that can use more information
about the query results.

Bug: 153387066
Bug: 140759491
Test: existing tests pass
Change-Id: I2ec967c763d33d7a3ff02c1a13c6953b460d1e5f

M room/compiler/src/main/kotlin/androidx/room/log/RLog.kt
M room/compiler/src/main/kotlin/androidx/room/processor/QueryMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/solver/TypeAdapterStore.kt
M room/compiler/src/main/kotlin/androidx/room/solver/query/result/PojoRowAdapter.kt

https://android-review.googlesource.com/1288456

du...@google.com <du...@google.com> #5Sep 5, 2020 06:32PM

This fix is slated to be released with alpha07, which should be the next one.

du...@google.com <du...@google.com> #6Sep 23, 2020 04:18AM

Spoke too soon, I had thought it had already merged, but looks like this will instead end up landing in alpha08

ap...@google.com <ap...@google.com> #7Oct 13, 2020 04:11PM

Marked as fixed.

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

commit 0680b894e3f13d0a93415a3cc0d9543135e179c5
Author: Dustin Lam <dustinlam@google.com>
Date: Thu Sep 03 20:19:24 2020

Ensure kotlin invalidate callbacks are called by WrapperDataSources

Relnote: "The Kotlin / Java variants of DataSource.InvalidatedCallback
have been combined by enabling SAM-conversions in Kotlin via functional
interface (available in Kotlin 1.4). This also fixes a bug where the
kotlin variant of invalidate callbacks were not called after transformed
by .map or .mapByPage."
Fixes: 165313046
Test: ./gradlew paging:paging-common:test
Change-Id: I1f244498bd9f78bfed2744d9e6c9d5c1c1448971

M paging/common/api/current.txt
M paging/common/api/public_plus_experimental_current.txt
M paging/common/api/restricted_current.txt
M paging/common/src/main/kotlin/androidx/paging/DataSource.kt
M paging/common/src/main/kotlin/androidx/paging/WrapperPageKeyedDataSource.kt
M paging/common/src/main/kotlin/androidx/paging/WrapperPositionalDataSource.kt
M paging/common/src/test/kotlin/androidx/paging/LegacyPagingSourceTest.kt
M paging/common/src/test/kotlin/androidx/paging/PagedListTest.kt
A paging/common/src/test/kotlin/androidx/paging/WrappedItemKeyedDataSourceTest.kt
A paging/common/src/test/kotlin/androidx/paging/WrappedPageKeyedDataSourceTest.kt
A paging/common/src/test/kotlin/androidx/paging/WrappedPositionalDataSourceTest.kt
M paging/runtime/src/androidTest/java/androidx/paging/AsyncPagedListDifferTest.kt
M paging/rxjava2/src/test/java/androidx/paging/RxPagedListBuilderTest.kt
A testutils/testutils-paging/src/main/java/androidx/paging/TestItemKeyedDataSource.kt
A testutils/testutils-paging/src/main/java/androidx/paging/TestPageKeyedDataSource.kt
M testutils/testutils-paging/src/main/java/androidx/paging/TestPositionalDataSource.kt

https://android-review.googlesource.com/1419738

Issue 165313046