feat: Generate properties for nested resource reference fields

Implements googleapis#545.

Test changes are for the specific tests for this use case, and for
Showcase which also contained resource references in nested messages.

Google.Api.Generator.Tests/ProtoTests/ResourceNames/Testing.ResourceNames/ResourceNamesResourceNames.g.cs

@@ -1568,5 +1568,45 @@ public SinglePatternName TopRefAsSinglePatternName
             get => string.IsNullOrEmpty(TopRef) ? null : SinglePatternName.Parse(TopRef, allowUnparsed: true);
             set => TopRef = value?.ToString() ?? "";
         }
+
+        public partial class Types
+        {
+            public partial class Nested
+            {
+                /// <summary>
+                /// <see cref="SinglePatternName"/>-typed view over the <see cref="NestedRef"/> resource name property.
+                /// </summary>
+                public SinglePatternName NestedRefAsSinglePatternName
+                {
+                    get => string.IsNullOrEmpty(NestedRef) ? null : SinglePatternName.Parse(NestedRef, allowUnparsed: true);
+                    set => NestedRef = value?.ToString() ?? "";
+                }
+            }
+        }
+    }
+
+    public partial class DeeplyNestedResourceReference
+    {
+        public partial class Types
+        {
+            public partial class Nested
+            {
+                public partial class Types
+                {
+                    public partial class DeeplyNested
+                    {
+                        /// <summary>
+                        /// <see cref="SinglePatternName"/>-typed view over the <see cref="Ref"/> resource name
+                        /// property.
+                        /// </summary>
+                        public SinglePatternName RefAsSinglePatternName
+                        {
+                            get => string.IsNullOrEmpty(Ref) ? null : SinglePatternName.Parse(Ref, allowUnparsed: true);
+                            set => Ref = value?.ToString() ?? "";
+                        }
+                    }
+                }
+            }
+        }
     }
 }

Google.Api.Generator.Tests/ProtoTests/Showcase/Google.Showcase.V1Beta1/MessagingResourceNames.g.cs

@@ -559,4 +559,22 @@ public partial class StreamBlurbsRequest
             set => Name = value?.ToString() ?? "";
         }
     }
+
+    public partial class ConnectRequest
+    {
+        public partial class Types
+        {
+            public partial class ConnectConfig
+            {
+                /// <summary>
+                /// <see cref="RoomName"/>-typed view over the <see cref="Parent"/> resource name property.
+                /// </summary>
+                public RoomName ParentAsRoomName
+                {
+                    get => string.IsNullOrEmpty(Parent) ? null : RoomName.Parse(Parent, allowUnparsed: true);
+                    set => Parent = value?.ToString() ?? "";
+                }
+            }
+        }
+    }
 }

Google.Api.Generator.Tests/ProtoTests/Showcase/Google.Showcase.V1Beta1/TestingResourceNames.g.cs

@@ -741,6 +741,21 @@ public partial class Test
             get => string.IsNullOrEmpty(Name) ? null : gsv::TestName.Parse(Name, allowUnparsed: true);
             set => Name = value?.ToString() ?? "";
         }
+
+        public partial class Types
+        {
+            public partial class Blueprint
+            {
+                /// <summary>
+                /// <see cref="gsv::BlueprintName"/>-typed view over the <see cref="Name"/> resource name property.
+                /// </summary>
+                public gsv::BlueprintName BlueprintName
+                {
+                    get => string.IsNullOrEmpty(Name) ? null : gsv::BlueprintName.Parse(Name, allowUnparsed: true);
+                    set => Name = value?.ToString() ?? "";
+                }
+            }
+        }
     }
 
     public partial class ListTestsRequest

Google.Api.Generator/Generation/ResourceNamesGenerator.cs

@@ -524,23 +524,41 @@ private IEnumerable<ClassDeclarationSyntax> ProtoMessagePartials()
         {
             // Note: Whether a field is required or optional is purposefully ignored in this partial class.
             // The optionalness of a field is only relevant within a method signature (flattening).
-            foreach (var msg in _fileDesc.MessageTypes)
+            foreach (var topLevelMessage in _fileDesc.MessageTypes)
             {
-                var resources = msg.Fields.InFieldNumberOrder()
-                    .Select(fieldDesc => (fieldDesc, resDetails: _catalog.GetResourceDetailsByField(fieldDesc)))
-                    .Where(x => x.resDetails != null)
+                // First find all resource-referencing fields for all messages recursively.
+                // We then pick only the relevant ones to generate on a per-message basis.
+                var allResources = topLevelMessage.SelfAndNestedMessagesRecursively()
+                    .SelectMany(m => m.Fields.InFieldNumberOrder())
+                    .Select(_catalog.GetResourceDetailsByField)
+                    .Where(x => x is not null)
+                    .SelectMany(r => r)
                     .ToList();
-                if (resources.Any())
+
+                var messagesContainingResources = allResources
+                    .Select(r => r.Descriptor.ContainingType)
+                    .SelectMany(m => m.SelfAndAncestors())
+                    .ToHashSet();
+
+                if (allResources.Any())
+                {
+                    yield return GenerateClassWithResourceReferences(topLevelMessage);
+                }
+
+                ClassDeclarationSyntax GenerateClassWithResourceReferences(MessageDescriptor msg)
                 {
-                    var cls = Class(Public | Partial, ProtoTyp.Of(msg));
+                    var messageOnlyResources = allResources.Where(r => r.Descriptor.ContainingType == msg).ToList();
+                    var msgTyp = ProtoTyp.Of(msg);
+                    var cls = Class(Public | Partial, msgTyp);
                     using (_ctx.InClass(cls))
                     {
-                        _ctx.RegisterClassMemberNames(resources
-                            .SelectMany(res => res.resDetails.Select(x => x.ResourcePropertyName))
-                            .Concat(msg.Fields.InDeclarationOrder().Select(f => f.CSharpPropertyName()))
-                            .Append(msg.NestedTypes.Any() ? "Types" : null)
-                            .Where(x => x != null));
-                        var properties = resources.SelectMany(res => res.resDetails).Select(field =>
+                        _ctx.RegisterClassMemberNames(
+                            messageOnlyResources.Select(x => x.ResourcePropertyName)
+                                .Concat(msg.Fields.InDeclarationOrder().Select(f => f.CSharpPropertyName()))
+                                .Append(msg.NestedTypes.Any() ? "Types" : null)
+                                .Where(x => x != null));
+                        // First generate the properties of this message.
+                        var properties = messageOnlyResources.Select(field =>
                         {
                             var def = field.ResourceDefinition;
                             var underlyingProperty = Property(DontCare, _ctx.TypeDontCare, field.UnderlyingPropertyName);
@@ -556,27 +574,40 @@ private IEnumerable<ClassDeclarationSyntax> ProtoMessagePartials()
                                     .Append(Return(_ctx.Type<UnparsedResourceName>().Call(nameof(UnparsedResourceName.Parse))(p)))) :
                                 p => Return(_ctx.Type<string>().Call(nameof(string.IsNullOrEmpty))(p).ConditionalOperator(
                                     Null, _ctx.Type(def.ResourceParserTyp).Call("Parse")(p, def.IsUnparsed ? null : (object) ("allowUnparsed", true))));
-                            if (field.IsRepeated)
+                            if (field.Descriptor.IsRepeated)
                             {
                                 var s = Parameter(null, "s");
                                 var repeatedTyp = Typ.Generic(typeof(ResourceNameList<>), def.ResourceNameTyp);
                                 return Property(Public, _ctx.Type(repeatedTyp), field.ResourcePropertyName)
-                                        .MaybeWithAttribute(field.IsDeprecated, () => _ctx.Type<ObsoleteAttribute>())()
+                                        .MaybeWithAttribute(field.Descriptor.IsDeprecated(), () => _ctx.Type<ObsoleteAttribute>())()
                                         .WithGetBody(Return(New(_ctx.Type(repeatedTyp))(underlyingProperty, Lambda(s)(getBodyFn(s)))))
                                         .WithXmlDoc(xmlDocSummary);
                             }
                             else
                             {
                                 return Property(Public, _ctx.Type(def.ResourceNameTyp), field.ResourcePropertyName)
-                                    .MaybeWithAttribute(field.IsDeprecated, () => _ctx.Type<ObsoleteAttribute>())()
+                                    .MaybeWithAttribute(field.Descriptor.IsDeprecated(), () => _ctx.Type<ObsoleteAttribute>())()
                                     .WithGetBody(getBodyFn(underlyingProperty))
                                     .WithSetBody(underlyingProperty.Assign(Value.Call(nameof(object.ToString), conditional: true)().NullCoalesce("")))
                                     .WithXmlDoc(xmlDocSummary);
                             }
                         });
                         cls = cls.AddMembers(properties.ToArray());
+
+                        // Now recursively generate any nested types with messages which need properties.
+                        var nestedMessagesWithResources = msg.NestedTypes.Where(messagesContainingResources.Contains).ToList();
+                        if (nestedMessagesWithResources.Any())
+                        {
+                            var types = Class(Public | Partial, Typ.Nested(msgTyp, "Types"));
+                            using var _ = _ctx.InClass(types);
+                            foreach (var nestedMessage in nestedMessagesWithResources)
+                            {
+                                types = types.AddMembers(GenerateClassWithResourceReferences(nestedMessage));
+                            }
+                            cls = cls.AddMembers(types);
+                        }
                     }
-                    yield return cls;
+                    return cls;
                 }
             }
         }

Google.Api.Generator/ProtoUtils/ProtoExtensions.cs

@@ -78,6 +78,32 @@ internal static string RemoveEnumPrefix(string enumName, string valueName)
             return valueName;
         }
 
+        /// <summary>
+        /// Returns a sequence of messages covering <paramref name="descriptor"/> and all nested messages within it,
+        /// recursively.
+        /// </summary>
+        internal static IEnumerable<MessageDescriptor> SelfAndNestedMessagesRecursively(this MessageDescriptor descriptor)
+        {
+            yield return descriptor;
+            foreach (var nestedType in descriptor.NestedTypes.SelectMany(SelfAndNestedMessagesRecursively))
+            {
+                yield return nestedType;
+            }
+        }
+
+        /// <summary>
+        /// Returns a sequence of messages covering <paramref name="descriptor"/> and all its ancestor message descriptors
+        /// (in terms of containing types).
+        /// </summary>
+        internal static IEnumerable<MessageDescriptor> SelfAndAncestors(this MessageDescriptor descriptor)
+        {
+            do
+            {
+                yield return descriptor;
+                descriptor = descriptor.ContainingType;
+            } while (descriptor is not null);
+        }
+
         public static string CSharpName(this EnumValueDescriptor desc) => RemoveEnumPrefix(desc.EnumDescriptor.Name, desc.Name);
 
         // Convenience methods for accessing extensions, where repeated extensions

Google.Api.Generator/ProtoUtils/ResourceDetails.cs

@@ -137,9 +137,7 @@ public class Field
             public Field(FieldDescriptor fieldDesc, Definition resourceDef, IReadOnlyList<Definition> innerDefs = null, bool? containsWildcard = null)
             {
                 // innerFields only non-null for the IResourceName property of child_type refs.
-                IsRepeated = fieldDesc.IsRepeated;
-                IsDeprecated = fieldDesc.IsDeprecated();
-                UnderlyingPropertyName = fieldDesc.CSharpPropertyName();
+                Descriptor = fieldDesc;
                 ResourceDefinition = resourceDef;
                 var requireIdentifier = !((fieldDesc.IsRepeated && fieldDesc.Name.ToLowerInvariant() == "names") ||
                     (!fieldDesc.IsRepeated && fieldDesc.Name.ToLowerInvariant() == "name"));
@@ -149,12 +147,13 @@ public Field(FieldDescriptor fieldDesc, Definition resourceDef, IReadOnlyList<De
                 ContainsWildcard = containsWildcard;
             }
 
-            public bool IsRepeated { get; }
-
-            public bool IsDeprecated { get; }
+            /// <summary>
+            /// The descriptor for the field which refers to the resource.
+            /// </summary>
+            public FieldDescriptor Descriptor { get; }
 
             /// <summary>The C# name of the string-typed property underlying this resource.</summary>
-            public string UnderlyingPropertyName { get; }
+            public string UnderlyingPropertyName => Descriptor.CSharpPropertyName();
 
             /// <summary>The C# name of the resource property.</summary>
             public string ResourcePropertyName { get; }