Fix up deserializing

src/ty/composite.rs

@@ -55,7 +55,7 @@ use serde::{Serialize, Deserialize, de::DeserializeOwned};
 ))]
 #[serde(rename_all = "lowercase")]
 pub struct TypeDefComposite<T: Form = MetaForm> {
-	#[serde(skip_serializing_if = "Vec::is_empty")]
+	#[serde(skip_serializing_if = "Vec::is_empty", default)]
 	fields: Vec<Field<T>>,
 }
 

src/ty/fields.rs

@@ -33,7 +33,7 @@ use serde::{Serialize, Deserialize, de::DeserializeOwned};
 ))]
 pub struct Field<T: Form = MetaForm> {
 	/// The name of the field. None for unnamed fields.
-	#[serde(skip_serializing_if = "Option::is_none")]
+	#[serde(skip_serializing_if = "Option::is_none", default)]
 	name: Option<T::String>,
 	/// The type of the field.
 	#[serde(rename = "type")]

src/ty/mod.rs

@@ -38,10 +38,10 @@ pub use self::{composite::*, fields::*, path::*, variant::*};
 ))]
 pub struct Type<T: Form = MetaForm> {
 	/// The unique path to the type. Can be empty for built-in types
-	#[serde(skip_serializing_if = "Path::is_empty")]
+	#[serde(skip_serializing_if = "Path::is_empty", default)]
 	path: Path<T>,
 	/// The generic type parameters of the type in use. Empty for non generic types
-	#[serde(rename = "params", skip_serializing_if = "Vec::is_empty")]
+	#[serde(rename = "params", skip_serializing_if = "Vec::is_empty", default)]
 	type_params: Vec<T::TypeId>,
 	/// The actual type definition
 	#[serde(rename = "def")]

src/ty/variant.rs

@@ -68,7 +68,7 @@ use serde::{Serialize, Deserialize, de::DeserializeOwned};
 ))]
 #[serde(rename_all = "lowercase")]
 pub struct TypeDefVariant<T: Form = MetaForm> {
-	#[serde(skip_serializing_if = "Vec::is_empty")]
+	#[serde(skip_serializing_if = "Vec::is_empty", default)]
 	variants: Vec<Variant<T>>,
 }
 
@@ -118,7 +118,7 @@ pub struct Variant<T: Form = MetaForm> {
 	/// The name of the struct variant.
 	name: T::String,
 	/// The fields of the struct variant.
-	#[serde(skip_serializing_if = "Vec::is_empty")]
+	#[serde(skip_serializing_if = "Vec::is_empty", default)]
 	fields: Vec<Field<T>>,
 	/// The discriminant of the variant.
 	///
@@ -127,7 +127,7 @@ pub struct Variant<T: Form = MetaForm> {
 	/// Even though setting the discriminant is optional
 	/// every C-like enum variant has a discriminant specified
 	/// upon compile-time.
-	#[serde(skip_serializing_if = "Option::is_none")]
+	#[serde(skip_serializing_if = "Option::is_none", default)]
 	discriminant: Option<u64>,
 }
 

test_suite/tests/codec.rs

@@ -55,3 +55,16 @@ fn scale_encode_then_decode_to_readonly() {
 
 	assert_eq!(decoded_serialized, original_serialized);
 }
+
+#[test]
+fn json_serialize_then_deserialize_to_readonly() {
+	let mut registry = Registry::new();
+	registry.register_type(&MetaType::new::<A<B>>());
+
+	let original_serialized = serde_json::to_value(registry).unwrap();
+	// assert_eq!(original_serialized, serde_json::Value::Null);
+	let readonly_deserialized: RegistryReadOnly = serde_json::from_value(original_serialized.clone()).unwrap();
+	let readonly_serialized = serde_json::to_value(readonly_deserialized).unwrap();
+
+	assert_eq!(readonly_serialized, original_serialized);
+}