tree 3751d2cc8031f75f0d5619e7694ca741d108485d
parent 194511be31cd7a97c85213cadf0763dee8e4af69
author Googler <noreply@google.com> 1581109264 -0800
committer Copybara-Service <copybara-worker@google.com> 1581109320 -0800

Add Support of Core Library Type Desugaring for Classes with Nest-based Access.

#java11 #desugar

Rationale:
- Context: Nest desugaring takes two passes of input class files. During the first pass, a nest analyzer collects class attributes without core library type renaming (i.e. __desugar__/ prefixing). During the second pass, core library types are renamed (by CoreLibrarySupport-enabled class visitors) before running nest-based desugaring (by NestDesugaring).
- This causes breakages that class attributes for core types cannot be found during NestDesugaring visiting. Potential Real issues:
   1) Java 11 core library with inter-mate private access cannot be desugared.
   2) IllegalStateExceptions/NullPointerExceptions even for prior Java 11, since ClassAttributes in langmode/ is not specific to NestHost/NestMembers, it is expected ClassAttributes is present for every input class during second pass to ensure state integrity. An blind null check would just hide the incorrect state and make wrong assumptions.

- Key Changes:
  - Add support type remapping for the nest summary object (NestDigest), including its recursively dependent data classes.
  - Rename NestCompanions to NestDigest; Move ClassMemberRecord APIs used by NestDesugaring to NestDigest; Remove the NestDesugaring's direct dependency on ClassMemberRecord, and let NestDesugaring only query with NestDigest for nest attribute info.
  - Create ClassName class in replacement of String-represented class binary names to get better name anchoring, conversions among different names and centralized checking.
  - Share and feed the core library renaming logic into NestDigest.
  - Add javadesugar/ package in par with java/ for easy testing.

PiperOrigin-RevId: 293876896