internal/impl: handle some dynamic legacy messages
When creating a MessageDescriptor for a legacy message with a
Descriptor method, we call that method on the type's zero value to
get the message's DescriptorProto. Some existing dynamic message
types have a Descriptor method which panics in this case.
Catch the panic and continue as if the Descriptor method wasn't present.
Change-Id: I98d4625d6917cc1ec25737e5670a443f5d02a404
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/206637
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
diff --git a/internal/impl/legacy_message.go b/internal/impl/legacy_message.go
index e078045..3d0a921 100644
--- a/internal/impl/legacy_message.go
+++ b/internal/impl/legacy_message.go
@@ -93,7 +93,20 @@
if !ok {
return aberrantLoadMessageDesc(t, name)
}
- b, idxs := mdV1.Descriptor()
+
+ // If this is a dynamic message type where there isn't a 1-1 mapping between
+ // Go and protobuf types, calling the Descriptor method on the zero value of
+ // the message type isn't likely to work. If it panics, swallow the panic and
+ // continue as if the Descriptor method wasn't present.
+ b, idxs := func() ([]byte, []int) {
+ defer func() {
+ recover()
+ }()
+ return mdV1.Descriptor()
+ }()
+ if b == nil {
+ return aberrantLoadMessageDesc(t, name)
+ }
md := legacyLoadFileDesc(b).Messages().Get(idxs[0])
for _, i := range idxs[1:] {