Call DescriptorPool::FindEnumValueByName in C++ don't work (return nullptr).

[lhh2001]

I have a proto file like this:

syntax = "proto3";

package test;

enum Foo {
  FOO_NONE = 0;
}

message Bar {
}

And I called FindEnumValueByName in cpp:

const auto EnumValueDesc = DescriptorPool::generated_pool()->FindEnumValueByName("test.FOO_NONE");  // EnumValueDesc = NULL

Then I got nullptr, but the wired thing is, if I called FindMessageTypeByName or FindEnumTypeByName on any type in the same package (not necessarily the very Foo enum type), it worked!

// Work, but WHYYYYYYYY?
const auto MessageDesc = DescriptorPool::generated_pool()->FindMessageTypeByName("test.Bar");
const auto EnumValueDesc = DescriptorPool::generated_pool()->FindEnumValueByName("test.FOO_NONE");

// Also work.
const auto EnumDesc = DescriptorPool::generated_pool()->FindEnumTypeByName("test.Foo");
const auto EnumValueDesc = DescriptorPool::generated_pool()->FindEnumValueByName("test.FOO_NONE");

Maybe it's some kind of bug?