IssueTracker

Due to the issues described in b/240600673, we have had to revert virtually all nullability annotations recently added to RecyclerView (except those specifically adding @Nullable to methods that cannot be overridden; this is the only safe change).

If that bug is fixed, we should put them back.

Relevant CLs containing the original changes: https://android-review.googlesource.com/q/file:%2522recyclerview%2522+file:%2522current.txt%2522+after:2022-06-14+before:2022-07-01+status:merged