In 2014, when proto3 was being developed, there were a number of early
adopters of the new syntax. Before the finalization of proto3 when
it was released in open-source in July 2016, a decision was made to
strictly validate strings in proto3. However, some of the early adopters
were already using invalid UTF-8 with string fields.
The google.protobuf.FieldOptions.enforce_utf8 option only exists to support
those grandfathered users where they can opt-out of the validation logic.
Practical use of that option in open source is impossible even if a user
specifies the proto1_legacy build tag since it requires a hacked
variant of descriptor.proto that is not externally available.
This CL supports enforce_utf8 by modifiyng internal/filedesc to
expose the flag if it detects it in the raw descriptor.
We add an strs.EnforceUTF8 function as a centralized place to determine
whether to perform validation. Validation opt-out is supported
only in builds with legacy support.
We implement support for validating UTF-8 in all proto3 string fields,
even if they are backed by a Go []byte.
Change-Id: I9c0628b84909bc7181125f09db730c80d490e485
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/186002
Reviewed-by: Damien Neil <dneil@google.com>
Create a new internal/strs package that unifies common functionality:
* Since protobuf itself pseudo-specifies at least 4 different camel-case
and snake-case conversion functions, we define all variants in one place.
* We move the internal/filedesc.nameBuilder function to this package.
We simplify its implementation to not depend on a strings.Builder fork
under the hood since the semantics we desire is simpler than what
strings.Builder provides.
* We use strs.Builder in reflect/protodesc in its construction of all
the full names. This is perfect use case of strs.Builder since all
full names within a file descriptor share the same lifetime.
* Add an UnsafeString and UnsafeBytes cast function that will be useful
in the near future for optimizing encoding/prototext and encoding/protojson.
Change-Id: I2cf07cbaf6f72e5f9fd6ae3d37b0d46f6af2ad59
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/185198
Reviewed-by: Damien Neil <dneil@google.com>
