Provide simple access to descriptor declarations in C#
This is primarily for access to comments, which would be expected to be available in a protoc plugin.
The implementation has two fiddly aspects:
- We use a Lazy<T> to avoid building the map before cross-linking. An alternative would be to crosslink at the end of the constructor, and remove the calls to CrossLink elsewhere. This would be generally better IMO, but deviate from the Java code.
- The casts to IReadOnlyList<DescriptorBase> are unfortunate. They'll always work, because these lists are always ReadOnlyCollection<T> for a descriptor type... but we can't use IList<DescriptorBase> as that's not covariant, and it's annoyingly fiddly to change the field to be of type ReadOnlyCollection<T>.
diff --git a/csharp/generate_protos.sh b/csharp/generate_protos.sh
index 5c748e3..31a4b90 100755
--- a/csharp/generate_protos.sh
+++ b/csharp/generate_protos.sh
@@ -43,6 +43,9 @@
# Test protos
$PROTOC -Isrc -Icsharp/protos \
--csharp_out=csharp/src/Google.Protobuf.Test/TestProtos \
+ --descriptor_set_out=csharp/src/Google.Protobuf.Test/testprotos.pb \
+ --include_source_info \
+ --include_imports \
csharp/protos/map_unittest_proto3.proto \
csharp/protos/unittest_issues.proto \
csharp/protos/unittest_custom_options_proto3.proto \
