all: rename tag and flags for legacy support
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>
diff --git a/internal/flags/flags.go b/internal/flags/flags.go
index 8208a6d..89b0aff 100644
--- a/internal/flags/flags.go
+++ b/internal/flags/flags.go
@@ -5,12 +5,13 @@
// Package flags provides a set of flags controlled by build tags.
package flags
-// Proto1Legacy specifies whether to enable support for legacy proto1
-// functionality such as MessageSets, weak fields, and various other obscure
-// behavior that is necessary to maintain backwards compatibility with proto1.
+// ProtoLegacy specifies whether to enable support for legacy functionality
+// such as MessageSets, weak fields, and various other obscure behavior
+// that is necessary to maintain backwards compatibility with proto1 or
+// the pre-release variants of proto2 and proto3.
//
-// This is disabled by default unless built with the "proto1_legacy" tag.
+// This is disabled by default unless built with the "protolegacy" tag.
//
// WARNING: The compatibility agreement covers nothing provided by this flag.
// As such, functionality may suddenly be removed or changed at our discretion.
-const Proto1Legacy = proto1Legacy
+const ProtoLegacy = protoLegacy