2 files changed, 30 insertions, 17 deletions

diff --git a/packages/backend/src/server/api/openapi/gen-spec.ts b/packages/backend/src/server/api/openapi/gen-spec.ts
index 0e71510b48..971a6116bf 100644
--- a/packages/backend/src/server/api/openapi/gen-spec.ts
+++ b/packages/backend/src/server/api/openapi/gen-spec.ts
@@ -10,7 +10,7 @@ import { schemas, convertSchemaToOpenApiSchema } from './schemas.js';
 
 export function genOpenapiSpec(config: Config) {
 	const spec = {
-		openapi: '3.0.0',
+		openapi: '3.1.0',
 
 		info: {
 			version: config.version,
@@ -56,7 +56,7 @@ export function genOpenapiSpec(config: Config) {
 			}
 		}
 
-		const resSchema = endpoint.meta.res ? convertSchemaToOpenApiSchema(endpoint.meta.res) : {};
+		const resSchema = endpoint.meta.res ? convertSchemaToOpenApiSchema(endpoint.meta.res, 'res') : {};
 
 		let desc = (endpoint.meta.description ? endpoint.meta.description : 'No description provided.') + '\n\n';
 
@@ -71,7 +71,7 @@ export function genOpenapiSpec(config: Config) {
 		}
 
 		const requestType = endpoint.meta.requireFile ? 'multipart/form-data' : 'application/json';
-		const schema = { ...endpoint.params };
+		const schema = { ...convertSchemaToOpenApiSchema(endpoint.params, 'param') };
 
 		if (endpoint.meta.requireFile) {
 			schema.properties = {
@@ -210,7 +210,9 @@ export function genOpenapiSpec(config: Config) {
 		};
 
 		spec.paths['/' + endpoint.name] = {
-			...(endpoint.meta.allowGet ? { get: info } : {}),
+			...(endpoint.meta.allowGet ? {
+				get: info,
+			} : {}),
 			post: info,
 		};
 	}
diff --git a/packages/backend/src/server/api/openapi/schemas.ts b/packages/backend/src/server/api/openapi/schemas.ts
index 2716f5f162..a862a7b742 100644
--- a/packages/backend/src/server/api/openapi/schemas.ts
+++ b/packages/backend/src/server/api/openapi/schemas.ts
@@ -6,32 +6,35 @@
 import type { Schema } from '@/misc/json-schema.js';
 import { refs } from '@/misc/json-schema.js';
 
-export function convertSchemaToOpenApiSchema(schema: Schema) {
-	// optional, refはスキーマ定義に含まれないので分離しておく
+export function convertSchemaToOpenApiSchema(schema: Schema, type: 'param' | 'res') {
+	// optional, nullable, refはスキーマ定義に含まれないので分離しておく
 	// eslint-disable-next-line @typescript-eslint/no-unused-vars
-	const { optional, ref, ...res }: any = schema;
+	const { optional, nullable, ref, ...res }: any = schema;
 
 	if (schema.type === 'object' && schema.properties) {
-		const required = Object.entries(schema.properties).filter(([k, v]) => !v.optional).map(([k]) => k);
-		if (required.length > 0) {
+		if (type === 'res') {
+			const required = Object.entries(schema.properties).filter(([k, v]) => !v.optional).map(([k]) => k);
+			if (required.length > 0) {
 			// 空配列は許可されない
-			res.required = required;
+				res.required = required;
+			}
 		}
 
 		for (const k of Object.keys(schema.properties)) {
-			res.properties[k] = convertSchemaToOpenApiSchema(schema.properties[k]);
+			res.properties[k] = convertSchemaToOpenApiSchema(schema.properties[k], type);
 		}
 	}
 
 	if (schema.type === 'array' && schema.items) {
-		res.items = convertSchemaToOpenApiSchema(schema.items);
+		res.items = convertSchemaToOpenApiSchema(schema.items, type);
 	}
 
-	if (schema.anyOf) res.anyOf = schema.anyOf.map(convertSchemaToOpenApiSchema);
-	if (schema.oneOf) res.oneOf = schema.oneOf.map(convertSchemaToOpenApiSchema);
-	if (schema.allOf) res.allOf = schema.allOf.map(convertSchemaToOpenApiSchema);
+	for (const o of ['anyOf', 'oneOf', 'allOf'] as const) {
+		// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+		if (o in schema) res[o] = schema[o]!.map(schema => convertSchemaToOpenApiSchema(schema, type));
+	}
 
-	if (schema.ref) {
+	if (type === 'res' && schema.ref) {
 		const $ref = `#/components/schemas/${schema.ref}`;
 		if (schema.nullable || schema.optional) {
 			res.allOf = [{ $ref }];
@@ -40,6 +43,14 @@ export function convertSchemaToOpenApiSchema(schema: Schema) {
 		}
 	}
 
+	if (schema.nullable) {
+		if (Array.isArray(schema.type) && !schema.type.includes('null')) {
+			res.type.push('null');
+		} else if (typeof schema.type === 'string') {
+			res.type = [res.type, 'null'];
+		}
+	}
+
 	return res;
 }
 
@@ -72,6 +83,6 @@ export const schemas = {
 	},
 
 	...Object.fromEntries(
-		Object.entries(refs).map(([key, schema]) => [key, convertSchemaToOpenApiSchema(schema)]),
+		Object.entries(refs).map(([key, schema]) => [key, convertSchemaToOpenApiSchema(schema, 'res')]),
 	),
 };