FieldDescriptor.HasPresence returns true if both ClearValue and HasValue (on the accessor) can be expected to work. Some fields have a working ClearValue, but no HasValue; HasPresence returns false for those fields.
Generally:
- Extension fields have presence if and only if they're singular
- Repeated fields do not support presence
- Map fields do not support presence
- Message fields support presence
- Oneof fields support presence (this includes synthetic oneof fields, so that covers proto3 optional singular fields)
- Proto2 singular primitive fields support presence
- Proto3 singular primitive fields do not support presence (unless they're in a oneof, covered above)
This is a breaking change in terms of proto2 code generation: users who were previously using these members will have to change to null checks for message fields.
After toying with removing Has/Clear for proto2 oneof fields, I've left them alone in this commit, for consistency with other languages. The inconsistency between proto2 and proto3 won't come up here, because proto3 oneof fields can never be explicitly optional.
Fixes#7395.
It is no longer possible to "bundle install" these versions:
$ bundle install
Fetching gem metadata from https://rubygems.org/.................
reline-0.1.3 requires ruby version >= 2.5, which is incompatible with the current version, ruby 2.4.9p362
This is a breaking change in terms of proto2 code generation: users who were previously using these members will have to change to null checks for message fields.
After toying with removing Has/Clear for proto2 oneof fields, I've left them alone in this commit, for consistency with other languages. The inconsistency between proto2 and proto3 won't come up here, because proto3 oneof fields can never be explicitly optional.
Fixes#7395.
* Added changelog for 3.12.x.
* Updated the wording of the changelog for proot3 presence.
Also removed notice for change that was rolled back for
Java enums.
* A bit more teaking of the wording.
Joshua Haberman
Evan Klitzke
Daniel Azuma
Protobuf Team
listonjesse
Jon Skeet
Jan Tattermusch
Paul Yang
Michael WERLE
Thomas Van Lenten
Nick Presta
Greg Steuck
Jan Tattermusch