IssueTracker

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

commit cfd1258a8911348898cd07d1b02b00d14917159d
Author: Yigit Boyar <yboyar@google.com>
Date:   Tue Dec 01 17:01:50 2020

    Ensure legacy data source is always created on the fetcher
   
    This CL fixes a bug where we could possibly create the legacy data
    source on the main thread (more specifically, the thread where flow
    collection happens).
    We already tried to prevent it by making it lazy, assuming the first
    call will be a loadInitial call but it is not the case for invalidations
    where we end up calling dataSource.isInvalid which might create it
    (lazy) and then call isInvalid. This issue became more appearant because
    Room's limit offset data source implementations might run a database
    query to check for invalidation, possibly causing ANR.
   
    In this CL, I changed the paging source factory to be a suspend function
    in Fetcher (it is internal class). Public API (Pager) still expects a
    regular function. To workaround it, now asPagingSource returns a known
    internal class (SuspendingPagingSourceFactory) which extends Function0
    but also has another suspend function to create the paging source.
   
    Pager, when initializing PageFetcher, checks the instance of the
    function to unwrap it before creating the fetcher.
   
    This WONT work if someone wraps that function but besides that, for the
    common case, this should fix the issue until we can move everyone off of
    Paging2 APIs, including Room.
   
    I've also slightly changed the legacy paging source implementation not
    to rely on overriding invalidate to be able to remove that method from
    public API.
   
    Bug: 173029013
    Bug: 137971356
    Test: LegacyPagingSourceTest
    RelNote: "PagingSource.invalidate is no longer an open function. If you
    need to get notified when invalidation happens, consider calling the
    registerInvalidatedCallback method instead of overriding invalidate."
   
    Change-Id: I628d9893a4ac55409aa24e49de1e2d2c35beda4f

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/LegacyPagingSource.kt
M       paging/common/src/main/kotlin/androidx/paging/PageFetcher.kt
M       paging/common/src/main/kotlin/androidx/paging/PagedList.kt
M       paging/common/src/main/kotlin/androidx/paging/Pager.kt
M       paging/common/src/main/kotlin/androidx/paging/PagingSource.kt
A       paging/common/src/main/kotlin/androidx/paging/SuspendingPagingSourceFactory.kt
M       paging/common/src/test/kotlin/androidx/paging/LegacyPagingSourceTest.kt
M       paging/common/src/test/kotlin/androidx/paging/PageFetcherSnapshotTest.kt
M       paging/common/src/test/kotlin/androidx/paging/PageFetcherTest.kt
M       paging/common/src/test/kotlin/androidx/paging/PageKeyedDataSourceTest.kt
M       paging/common/src/test/kotlin/androidx/paging/PagedListTest.kt
M       paging/runtime/src/androidTest/java/androidx/paging/AsyncPagedListDifferTest.kt
M       testutils/testutils-common/src/main/java/androidx/testutils/TestExecutor.kt

https://android-review.googlesource.com/1515484