Type URLs can have any host and even include URI scheme

[jhump]

The previous implementation assumed that the type_url field in an Any would always have a type.googleapis.com/ prefix. Though that is typical in practice, it is not actually required per the spec for that field. In fact, protoc allows the use of Any messages (inside message literals for complex option values) that contain a prefix of type.googleprod.com/ (therefore, so does the buf CLI).

The way all protobuf runtimes handle Any is to instead look at the last path element and ignore the prefix (which is also mentioned in the spec for the type_url field). So this makes the code more resilient to unexpected values for type URLs. Previously, the ErrorDetail.Type() method would return the full URL, instead of the type name, in the event that the URL had an unexpected prefix.

[akshayjshah]

Good catch!