Allow passing ResultContext from server to the client through grpcerror

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>

controller/errdefs/build.go

@@ -0,0 +1,34 @@
+package errdefs
+
+import (
+	"github.com/containerd/typeurl/v2"
+	"github.com/moby/buildkit/util/grpcerrors"
+)
+
+func init() {
+	typeurl.Register((*Build)(nil), "github.com/docker/buildx", "errdefs.Build+json")
+}
+
+type BuildError struct {
+	Build
+	error
+}
+
+func (e *BuildError) Unwrap() error {
+	return e.error
+}
+
+func (e *BuildError) ToProto() grpcerrors.TypedErrorProto {
+	return &e.Build
+}
+
+func WrapBuild(err error, ref string) error {
+	if err == nil {
+		return nil
+	}
+	return &BuildError{Build: Build{Ref: ref}, error: err}
+}
+
+func (b *Build) WrapError(err error) error {
+	return &BuildError{error: err, Build: *b}
+}