tree ed403c9781d99aa62ea1d029ef810420c727b7e2
parent 8e9d5f6e8a0687384bc0db5f6188b49e724c5e5c
author Joe Tsai <joetsai@digital-static.net> 1570226326 -0700
committer Joe Tsai <joetsai@digital-static.net> 1570332532 +0000

reflect/protoregistry: protect global registries with a lock

The global registry is initialized via generated code.
The Go language guarantees that these are serialized (non concurrently).
The main concern is when a concurrent read operation occurs while
registration is still ongoing. In such a case, we do need a lock to
serialize the read with regard to the writes (i.e. registrations).

Change-Id: Ied35d6f8d2620f448cb281c3ec46d8de893b5671
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/199217
Reviewed-by: Damien Neil <dneil@google.com>