protobuf-go/reflect/protoreflect
Damien Neil d4f0800c42 all: make handling of zero-value composites more consistent
We occasionally need to work with immutable, empty lists, maps, and
messages. Notably, Message.Get on an empty repeated field will return a
"frozen" empty value.

Move handling of these immutable, zero-length composites into Converter,
to unify the behavior of regular and extension fields.

Add a Zero method to Converter, MessageType, and ExtensionType, to
provide a consistent way to get an empty, frozen value of a composite
type. Adding this method to the public {Message,Extension}Type
interfaces does increase our API surface, but lets us (for example)
cleanly represent an empty map as a nil map rather than a non-nil
one wrapped in a frozenMap type.

Drop the frozen{List,Map,Message} types as no longer necessary.
(These types did have support for creating a read-only view of a
non-empty value, but we are not currently using that feature.)

Change-Id: Ia76f149d591da07b40ce75b7404a7ab8a60cb9d8
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/189339
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
2019-08-08 18:20:25 +00:00
..
proto_test.go reflect/protoreflect: initial commit 2018-08-10 19:59:50 +00:00
proto.go reflect/protoreflect: print unknown number in String methods 2019-06-24 23:34:46 +00:00
source.go reflect/protoreflect: add FileDescriptor.SourceLocations 2019-07-13 00:15:59 +00:00
type.go all: make handling of zero-value composites more consistent 2019-08-08 18:20:25 +00:00
value_pure.go all: change module to google.golang.org/protobuf 2019-05-14 17:28:29 +00:00
value_test.go all: rename Vector as List 2018-11-14 23:03:53 +00:00
value_union.go reflect/protoreflect: add alternative message reflection API 2019-06-17 17:33:24 +00:00
value_unsafe.go all: change module to google.golang.org/protobuf 2019-05-14 17:28:29 +00:00
value.go all: add NewField, NewElement, NewValue 2019-08-06 21:54:30 +00:00