Improve handling of internally tagged enum with newtypes

schemars/tests/integration/snapshots/schemars/tests/integration/enums.rs~internally_tagged_enum.json

@@ -22,9 +22,14 @@
  "const": "StringMap"
  }
  },
- "additionalProperties": {
- "type": "string"
- },
+ "allOf": [
+ {
+ "type": "object",
+ "additionalProperties": {
+ "type": "string"
+ }
+ }
+ ],
  "required": [
  "tag"
  ]
@@ -44,22 +49,18 @@
  {
  "type": "object",
  "properties": {
- "foo": {
- "type": "integer",
- "format": "int32"
- },
- "bar": {
- "type": "boolean"
- },
  "tag": {
  "type": "string",
  "const": "StructNewType"
  }
  },
+ "allOf": [
+ {
+ "$ref": "#/$defs/Struct"
+ }
+ ],
  "required": [
- "tag",
- "foo",
- "bar"
+ "tag"
  ]
  },
  {
@@ -95,5 +96,23 @@
  "tag"
  ]
  }
- ]
+ ],
+ "$defs": {
+ "Struct": {
+ "type": "object",
+ "properties": {
+ "foo": {
+ "type": "integer",
+ "format": "int32"
+ },
+ "bar": {
+ "type": "boolean"
+ }
+ },
+ "required": [
+ "foo",
+ "bar"
+ ]
+ }
+ }
 }

schemars/tests/integration/snapshots/schemars/tests/integration/enums_deny_unknown_fields.rs~internally_tagged_enum.json

@@ -23,9 +23,31 @@
  "const": "StringMap"
  }
  },
- "additionalProperties": {
- "type": "string"
+ "allOf": [
+ {
+ "type": "object",
+ "additionalProperties": {
+ "type": "string"
+ }
+ }
+ ],
+ "required": [
+ "tag"
+ ]
+ },
+ {
+ "type": "object",
+ "properties": {
+ "tag": {
+ "type": "string",
+ "const": "StructNewType"
+ }
  },
+ "allOf": [
+ {
+ "$ref": "#/$defs/Struct"
+ }
+ ],
  "required": [
  "tag"
  ]
@@ -42,16 +64,19 @@
  },
  "tag": {
  "type": "string",
- "const": "StructNewType"
+ "const": "Struct"
  }
  },
+ "additionalProperties": false,
  "required": [
  "tag",
  "foo",
  "bar"
  ]
- },
- {
+ }
+ ],
+ "$defs": {
+ "Struct": {
  "type": "object",
  "properties": {
  "foo": {
@@ -60,18 +85,12 @@
  },
  "bar": {
  "type": "boolean"
- },
- "tag": {
- "type": "string",
- "const": "Struct"
  }
  },
- "additionalProperties": false,
  "required": [
- "tag",
  "foo",
  "bar"
  ]
  }
- ]
+ }
 }

schemars/tests/integration/snapshots/schemars/tests/integration/extend.rs~extend_internally_tagged_enum.json

@@ -23,6 +23,9 @@
  "const": "NewType"
  }
  },
+ "allOf": [
+ true
+ ],
  "required": [
  "t"
  ],

schemars_derive/src/schema_exprs.rs

@@ -136,6 +136,50 @@ fn expr_for_field(field: &Field, allow_ref: bool) -> SchemaExpr {
  schema_expr
 }
 
+fn expr_for_internally_tagged_newtype_field(field: &Field) -> SchemaExpr {
+ let (ty, type_def) = type_for_field_schema(field);
+ let span = field.original.span();
+
+ let mut schema_expr = SchemaExpr::from(if field.attrs.validation.required {
+ quote_spanned! {span=>
+ <#ty as schemars::JsonSchema>::_schemars_private_non_optional_json_schema(#GENERATOR)
+ }
+ } else {
+ let keyword = "allOf";
+ quote_spanned!(span =>
+ {
+ if (#GENERATOR.settings().inline_subschemas) {
+ <#ty as schemars::JsonSchema>::json_schema(#GENERATOR)
+ } else {
+ let subschema = <#ty as schemars::JsonSchema>::json_schema(#GENERATOR);
+ let subschema_type = subschema.get("type");
+ let is_null_type = subschema_type.is_some() && subschema_type.unwrap().as_str().unwrap() == "null";
+ if !is_null_type {
+ let mut map = schemars::_private::serde_json::Map::new();
+ map.insert(
+ #keyword.into(),
+ schemars::_private::serde_json::Value::Array({
+ let mut enum_values = schemars::_private::alloc::vec::Vec::new();
+ enum_values.push(#GENERATOR.subschema_for::<#ty>().to_value());
+ enum_values
+ }),
+
+ );
+ schemars::Schema::from(map)
+ } else {
+ <#ty as schemars::JsonSchema>::json_schema(#GENERATOR)
+ }
+ }
+ }
+ )
+ });
+
+ schema_expr.definitions.extend(type_def);
+ field.add_mutators(&mut schema_expr.mutators);
+
+ schema_expr
+}
+
 pub fn type_for_field_schema(field: &Field) -> (syn::Type, Option<TokenStream>) {
  match &field.attrs.with {
  None => (field.ty.to_owned(), None),
@@ -430,7 +474,7 @@ fn expr_for_internal_tagged_enum_variant(
 
  match variant.style {
  Style::Unit => expr_for_unit_struct(),
- Style::Newtype => expr_for_field(&variant.fields[0], false),
+ Style::Newtype => expr_for_internally_tagged_newtype_field(&variant.fields[0]),
  Style::Tuple => expr_for_tuple_struct(&variant.fields),
  Style::Struct => expr_for_struct(&variant.fields, &SerdeDefault::None, deny_unknown_fields),
  }