Implement support in the protobuf runtime to better understand
message types that are not generated by the official generator.
In particular:
* Add a best-effort implementation of protobuf reflection for
"non-nullable" fields which are supposed to be represented by *T,
but are instead represented by a T. "Non-nullable" message fields
report presence based on whether the message is the zero Go value.
* We do NOT implement support for "non-nullable" fields in the
table-driven implementation since we assume that the aberrant messages
that we care about have a Marshal and Unmarshal method.
* We better handle custom messages that implement Marshal and Unmarshal,
but do NOT implement Merge. In that case, we implement merge in terms of
a back-to-back marshal and unmarshal.
* We better tolerate the situations where a protobuf message field
cannot be mapped to a Go struct field since the latter is missing.
In such cases, reflection treats the field as if it were unpopulated.
Setting such fields will panic.
This change allows the runtime to handle all message types declared
in the "go.etcd.io/etcd" and "k8s.io" modules where protobuf reflection,
Marshal, Unmarshal, Reset, Merge, and Equal all work.
The only types that still do not fully work are:
* "k8s.io/api/authentication/v1".ExtraValue
* "k8s.io/api/authentication/v1beta1".ExtraValue
* "k8s.io/api/authorization/v1".ExtraValue
* "k8s.io/api/authorization/v1beta1".ExtraValue
* "k8s.io/api/certificates/v1".ExtraValue
* "k8s.io/api/certificates/v1beta1".ExtraValue
* "k8s.io/apimachinery/pkg/apis/meta/v1".MicroTime
* "k8s.io/apimachinery/pkg/apis/meta/v1".Time
* "k8s.io/apimachinery/pkg/apis/meta/v1".Verbs
While Marshal, Unmarshal, Reset, and Merge continue to work,
protobuf reflection and any functionality that depends on it
(e.g., prototext, protojson, Equal, etc.) will not work.
Change-Id: I67a9d2f1bec35248045ad0c16220d02fc2e0e172
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/300869
Trust: Joe Tsai <joetsai@digital-static.net>
Trust: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Damien Neil <dneil@google.com>
Changes made:
* Ensure protoreflect.ExtensionType.IsValidInterface never panics,
especially if given a nil interface value.
* Have protoreflect.ExtensionType.IsValid{Interface,Value} only
perform type-checks. It does not do value checks (i.e., whether the
value itself is valid). Value validity is left to when an actual
protoreflect.Message.Set operation is performed.
* Add special-casing on proto.SetExtension to treat an invalid
message or list as functionally equivalent to Clear. This is to
be more consistent with the legacy SetExtension implementation
which never panicked when given such values.
* Add special-casing on proto.HasExtension to treat a mismatched
extension descriptor as simply not being present in the message.
This is also to be more consistent with the legacy HasExtension
implementation which did the same thing.
Change-Id: Idf0419abf27b9f85d9b92bd2ff8088e25b7990cc
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/229558
Reviewed-by: Damien Neil <dneil@google.com>
This interface is only ever used within the impl package.
Unexport it to avoid potential abuse by users.
Change-Id: I58d0cc2e8cb01c8c9d36cdec469c8d2196c4f836
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/193197
Reviewed-by: Damien Neil <dneil@google.com>
Add a way to typecheck a Value or interface{} without converting it to
the other form. This permits implementations which store field values as
a Value (such as dynamicpb, or (soon) extensions in generated messages)
to validate inputs without an unnecessary conversion.
Fixesgolang/protobuf#905
Change-Id: I1b78612b22ae832efbb55f81ae420871729e3a02
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/192457
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Passing a non-pointer type to protoreflect.NewValue causes an
unnecessary allocation in order to store the value in an interface{}.
While this allocation could be avoided by a smarter compiler, no such
compiler exists today.
Add functions for creating new values of a specific type, avoiding the
allocation. (And also adding a small amount of type safety, although
this is unlikely to be important.)
Update the proto and internal/impl packages to use these functions.
Change-Id: Ic733de22ddf19c530189166c853348e1b54b7391
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/191457
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
We occasionally need to work with immutable, empty lists, maps, and
messages. Notably, Message.Get on an empty repeated field will return a
"frozen" empty value.
Move handling of these immutable, zero-length composites into Converter,
to unify the behavior of regular and extension fields.
Add a Zero method to Converter, MessageType, and ExtensionType, to
provide a consistent way to get an empty, frozen value of a composite
type. Adding this method to the public {Message,Extension}Type
interfaces does increase our API surface, but lets us (for example)
cleanly represent an empty map as a nil map rather than a non-nil
one wrapped in a frozenMap type.
Drop the frozen{List,Map,Message} types as no longer necessary.
(These types did have support for creating a read-only view of a
non-empty value, but we are not currently using that feature.)
Change-Id: Ia76f149d591da07b40ce75b7404a7ab8a60cb9d8
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/189339
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Add methods to protoreflect.{Message,List,Map} to constrict values
assignable to a message field, list element, or map value. These
methods return the default value for scalar fields, the zero value for
scalar list elements and map values, and an empty, mutable value for
messages, lists, and maps.
Deprecate the NewMessage methods on these types, which are superseded.
Updates golang/protobuf#879
Change-Id: I0f064f60c89a239330ccea81523f559f14fd2c4f
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/188997
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
A Converter converts between reflect.Values and protoreflect.Values.
The existing usage of Converter is somewhat confusing: The
internal/value package creates Converters for scalar types only, the
internal/impl package creates Converters for legacy messages and enums,
and the reflect/prototype package creates Converters for repeated fields.
Change the Converter type to an interface. The constructor for
Converter takes a FieldDescriptor and reflect.Type, and directly
handles conversions for all field types: Scalars, lists, maps, and
legacy types.
Move Converter into the internal/impl package, since that package
contains the necessary support for dealing with legacy messages and
enums. Drop the internal/value package.
Replace two uses of prototype.Extension with more focused
implementations, since the implementation is trivial with the
refactored Converter. Drop prototype.Extension for the moment since
it is now unused.
Change-Id: If0c570fefac002cc5925b3d56281b6eb17e90d5f
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/187857
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
