Change where we rename Descriptor.cs to DescriptorProtoFile.cs.

We now do this in protoc instead of the generation simpler.

Benefits:
- Generation script is simpler
- Detection is simpler as we now only need to care about one filename
- The embedded descriptor knows itself as "google/protobuf/descriptor.proto" avoiding dependency issues

This PR also makes the "invalid dependency" exception clearer in terms of expected and actual dependencies.

1 files changed, 3 insertions, 2 deletions

diff --git a/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs
index bad58faa..45862aff 100644
--- a/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs
@@ -300,8 +300,9 @@ namespace Google.Protobuf.Reflection
                 if (dependencies[i].Name != proto.Dependency[i])
                 {
                     throw new DescriptorValidationException(result,
-                                                            "Dependencies passed to FileDescriptor.BuildFrom() don't match " +
-                                                            "those listed in the FileDescriptorProto.");
+                        "Dependencies passed to FileDescriptor.BuildFrom() don't match " +
+                        "those listed in the FileDescriptorProto. Expected: " +
+                        proto.Dependency[i] + " but was: " + dependencies[i].Name);
                 }
             }