tree 84b57cde187d41050c4d4bfbe99461856f3fc7f8
parent 44e4150b302bcb42b8c2fad97e7be5fd89032bb5
author Joe Tsai <joetsai@digital-static.net> 1592335070 -0700
committer Joe Tsai <thebrokentoaster@gmail.com> 1592342326 +0000

types/known: handle nil in IsValid and CheckValid methods

Many usages of the legacy ptypes.Timestamp and ptypes.Duration rely
on the functions implicitly returning an error for a nil message.
In order to migrate previous usages of the ptypes constructors to
the new API, we modify CheckValid to preserve similar semantics.

There is some consistency with this change in that:
	(*M)(nil).IsValid() == (*M)(nil).ProtoReflect().IsValid()
where M is Duration, Timestamp, and FieldMask.

Change-Id: I05ae152511f9875ea034e78aefb7aab18d17a318
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/238007
Reviewed-by: Damien Neil <dneil@google.com>