encoding/protobuf: make oneOf fields required
This is not exactly correct, but closer to what is needed
in practice. Once we have closed structs, we can fix
the semantics again.
Change-Id: Ia88cc2971aca330b6edc4113680721f72cf250a2
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/2800
Reviewed-by: Jason Wang <jasonwzm@google.com>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/encoding/protobuf/parse.go b/encoding/protobuf/parse.go
index 8280f06..9f49916 100644
--- a/encoding/protobuf/parse.go
+++ b/encoding/protobuf/parse.go
@@ -641,9 +641,19 @@
addComments(enum.Value, 1, nil, lastComment)
}
+// oneOf converts a Proto OneOf field to CUE. Note that Protobuf defines
+// a oneOf to be at most one of the fields. Rather than making each field
+// optional, we define oneOfs as all required fields, but add one more
+// disjunction allowing no fields. This makes it easier to constrain the
+// result to include at least one of the values.
func (p *protoConverter) oneOf(x *proto.Oneof) {
f := &ast.Field{
Label: p.ref(x.Position),
+ // TODO: Once we have closed structs, a oneOf is represented as a
+ // disjunction of empty structs and closed structs with required fields.
+ // For now we just specify the required fields. This is not correct
+ // but more practical.
+ // Value: &ast.StructLit{}, // Remove to make at least one required.
}
f.AddComment(comment(x.Comment, true))
@@ -656,7 +666,8 @@
}
switch x := v.(type) {
case *proto.OneOfField:
- p.parseField(s, 0, x.Field)
+ oneOf := p.parseField(s, 0, x.Field)
+ oneOf.Optional = token.NoPos
default:
p.messageField(s, 1, v)
