Change the storage type of ExtensionField from interface{} to
protoreflect.Value.
Replace the codec functions operating on interface{}s with ones
operating on Values.
Values are potentially more efficient, since they can represent
non-pointer types without allocation. This also reduces the number of
types used to represent field values.
Additionally, this change lays groundwork for changing the
user-visible representation of repeated extension fields from
*[]T to []T. The storage type for extension fields must support mutation
(thus *[]T currently); changing the storage type to a Value permits this
without the need to introduce yet another view on field values.
Change-Id: Ida336be14112bb940f655236eb58df21bf312525
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/192218
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Rename build tag "proto1_legacy" -> "protolegacy"
to be consistent with the "protoreflect" tag.
Rename flag constant "Proto1Legacy" -> "ProtoLegacy" since
it covers more than simply proto1 legacy features.
For example, it covers alpha-features of proto3 that
were eventually removed from the final proto3 release.
Change-Id: I0f4fcbadd4b5a61c87645e2e5be11d187e59157c
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/189345
Reviewed-by: Damien Neil <dneil@google.com>
MessageSets are a deprecated proto1 feature, long since superseded by
extensions. Add disabled-by-default support behind flags.Proto1Legacy.
Change-Id: I7d3ace07f3b0efd59673034f3dc633b908345a88
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/185538
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
