fix(backend): correct invalid schema format specifying only `required` for `anyOf` (#16089)

* fix(backend): correct invalid schema format specifying only `required` for `anyOf`

* refactor(backend): make types derived from `allOf` or `anyOf` more strong

6 files changed, 162 insertions, 72 deletions

diff --git a/packages/backend/src/server/api/endpoints/users/followers.ts b/packages/backend/src/server/api/endpoints/users/followers.ts
index a8b4319a61..bb8d4c49e9 100644
--- a/packages/backend/src/server/api/endpoints/users/followers.ts
+++ b/packages/backend/src/server/api/endpoints/users/followers.ts
@@ -47,23 +47,38 @@ export const meta = {
 } as const;
 
 export const paramDef = {
-	type: 'object',
-	properties: {
-		sinceId: { type: 'string', format: 'misskey:id' },
-		untilId: { type: 'string', format: 'misskey:id' },
-		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
-
-		userId: { type: 'string', format: 'misskey:id' },
-		username: { type: 'string' },
-		host: {
-			type: 'string',
-			nullable: true,
-			description: 'The local host is represented with `null`.',
+	allOf: [
+		{
+			anyOf: [
+				{
+					type: 'object',
+					properties: {
+						userId: { type: 'string', format: 'misskey:id' },
+					},
+					required: ['userId'],
+				},
+				{
+					type: 'object',
+					properties: {
+						username: { type: 'string' },
+						host: {
+							type: 'string',
+							nullable: true,
+							description: 'The local host is represented with `null`.',
+						},
+					},
+					required: ['username', 'host'],
+				},
+			],
+		},
+		{
+			type: 'object',
+			properties: {
+				sinceId: { type: 'string', format: 'misskey:id' },
+				untilId: { type: 'string', format: 'misskey:id' },
+				limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+			},
 		},
-	},
-	anyOf: [
-		{ required: ['userId'] },
-		{ required: ['username', 'host'] },
 	],
 } as const;
 
@@ -85,9 +100,9 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		private roleService: RoleService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
-			const user = await this.usersRepository.findOneBy(ps.userId != null
+			const user = await this.usersRepository.findOneBy('userId' in ps
 				? { id: ps.userId }
-				: { usernameLower: ps.username!.toLowerCase(), host: this.utilityService.toPunyNullable(ps.host) ?? IsNull() });
+				: { usernameLower: ps.username.toLowerCase(), host: this.utilityService.toPunyNullable(ps.host) ?? IsNull() });
 
 			if (user == null) {
 				throw new ApiError(meta.errors.noSuchUser);
diff --git a/packages/backend/src/server/api/endpoints/users/following.ts b/packages/backend/src/server/api/endpoints/users/following.ts
index feda5bb353..1fc87151b2 100644
--- a/packages/backend/src/server/api/endpoints/users/following.ts
+++ b/packages/backend/src/server/api/endpoints/users/following.ts
@@ -54,25 +54,39 @@ export const meta = {
 } as const;
 
 export const paramDef = {
-	type: 'object',
-	properties: {
-		sinceId: { type: 'string', format: 'misskey:id' },
-		untilId: { type: 'string', format: 'misskey:id' },
-		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
-
-		userId: { type: 'string', format: 'misskey:id' },
-		username: { type: 'string' },
-		host: {
-			type: 'string',
-			nullable: true,
-			description: 'The local host is represented with `null`.',
+	allOf: [
+		{
+			anyOf: [
+				{
+					type: 'object',
+					properties: {
+						userId: { type: 'string', format: 'misskey:id' },
+					},
+					required: ['userId'],
+				},
+				{
+					type: 'object',
+					properties: {
+						username: { type: 'string' },
+						host: {
+							type: 'string',
+							nullable: true,
+							description: 'The local host is represented with `null`.',
+						},
+					},
+					required: ['username', 'host'],
+				},
+			],
+		},
+		{
+			type: 'object',
+			properties: {
+				sinceId: { type: 'string', format: 'misskey:id' },
+				untilId: { type: 'string', format: 'misskey:id' },
+				limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+				birthday: { ...birthdaySchema, nullable: true },
+			},
 		},
-
-		birthday: { ...birthdaySchema, nullable: true },
-	},
-	anyOf: [
-		{ required: ['userId'] },
-		{ required: ['username', 'host'] },
 	],
 } as const;
 
@@ -94,9 +108,9 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		private roleService: RoleService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
-			const user = await this.usersRepository.findOneBy(ps.userId != null
+			const user = await this.usersRepository.findOneBy('userId' in ps
 				? { id: ps.userId }
-				: { usernameLower: ps.username!.toLowerCase(), host: this.utilityService.toPunyNullable(ps.host) ?? IsNull() });
+				: { usernameLower: ps.username.toLowerCase(), host: this.utilityService.toPunyNullable(ps.host) ?? IsNull() });
 
 			if (user == null) {
 				throw new ApiError(meta.errors.noSuchUser);
diff --git a/packages/backend/src/server/api/endpoints/users/relation.ts b/packages/backend/src/server/api/endpoints/users/relation.ts
index 1d75437b81..f146095cf1 100644
--- a/packages/backend/src/server/api/endpoints/users/relation.ts
+++ b/packages/backend/src/server/api/endpoints/users/relation.ts
@@ -114,7 +114,7 @@ export const paramDef = {
 	type: 'object',
 	properties: {
 		userId: {
-			anyOf: [
+			oneOf: [
 				{ type: 'string', format: 'misskey:id' },
 				{
 					type: 'array',
diff --git a/packages/backend/src/server/api/endpoints/users/search-by-username-and-host.ts b/packages/backend/src/server/api/endpoints/users/search-by-username-and-host.ts
index 134f1a8e87..d1d6354d53 100644
--- a/packages/backend/src/server/api/endpoints/users/search-by-username-and-host.ts
+++ b/packages/backend/src/server/api/endpoints/users/search-by-username-and-host.ts
@@ -26,17 +26,32 @@ export const meta = {
 } as const;
 
 export const paramDef = {
-	type: 'object',
-	properties: {
-		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
-		detail: { type: 'boolean', default: true },
-
-		username: { type: 'string', nullable: true },
-		host: { type: 'string', nullable: true },
-	},
-	anyOf: [
-		{ required: ['username'] },
-		{ required: ['host'] },
+	allOf: [
+		{
+			anyOf: [
+				{
+					type: 'object',
+					properties: {
+						username: { type: 'string', nullable: true },
+					},
+					required: ['username'],
+				},
+				{
+					type: 'object',
+					properties: {
+						host: { type: 'string', nullable: true },
+					},
+					required: ['host'],
+				},
+			],
+		},
+		{
+			type: 'object',
+			properties: {
+				limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+				detail: { type: 'boolean', default: true },
+			},
+		},
 	],
 } as const;
 
@@ -47,8 +62,8 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 	) {
 		super(meta, paramDef, (ps, me) => {
 			return this.userSearchService.searchByUsernameAndHost({
-				username: ps.username,
-				host: ps.host,
+				username: 'username' in ps ? ps.username : undefined,
+				host: 'host' in ps ? ps.host : undefined,
 			}, {
 				limit: ps.limit,
 				detail: ps.detail,
diff --git a/packages/backend/src/server/api/endpoints/users/show.test.ts b/packages/backend/src/server/api/endpoints/users/show.test.ts
new file mode 100644
index 0000000000..068ffd8bc9
--- /dev/null
+++ b/packages/backend/src/server/api/endpoints/users/show.test.ts
@@ -0,0 +1,23 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+process.env.NODE_ENV = 'test';
+
+import { getValidator } from '../../../../../test/prelude/get-api-validator.js';
+import { paramDef } from './show.js';
+
+const VALID = true;
+const INVALID = false;
+
+describe('api:users/show', () => {
+	describe('validation', () => {
+		const v = getValidator(paramDef);
+
+		test('Reject empty', () => expect(v({})).toBe(INVALID));
+		test('Reject host only', () => expect(v({ host: 'misskey.test' })).toBe(INVALID));
+		test('Accept userId only', () => expect(v({ userId: '1' })).toBe(VALID));
+		test('Accept username and host', () => expect(v({ username: 'alice', host: 'misskey.test' })).toBe(VALID));
+	});
+});
diff --git a/packages/backend/src/server/api/endpoints/users/show.ts b/packages/backend/src/server/api/endpoints/users/show.ts
index 431869d47f..d57db42e6d 100644
--- a/packages/backend/src/server/api/endpoints/users/show.ts
+++ b/packages/backend/src/server/api/endpoints/users/show.ts
@@ -59,23 +59,44 @@ export const meta = {
 } as const;
 
 export const paramDef = {
-	type: 'object',
-	properties: {
-		userId: { type: 'string', format: 'misskey:id' },
-		userIds: { type: 'array', uniqueItems: true, items: {
-			type: 'string', format: 'misskey:id',
-		} },
-		username: { type: 'string' },
-		host: {
-			type: 'string',
-			nullable: true,
-			description: 'The local host is represented with `null`.',
+	allOf: [
+		{
+			anyOf: [
+				{
+					type: 'object',
+					properties: {
+						userId: { type: 'string', format: 'misskey:id' },
+					},
+					required: ['userId'],
+				},
+				{
+					type: 'object',
+					properties: {
+						userIds: { type: 'array', uniqueItems: true, items: {
+							type: 'string', format: 'misskey:id',
+						} },
+					},
+					required: ['userIds'],
+				},
+				{
+					type: 'object',
+					properties: {
+						username: { type: 'string' },
+					},
+					required: ['username'],
+				},
+			],
+		},
+		{
+			type: 'object',
+			properties: {
+				host: {
+					type: 'string',
+					nullable: true,
+					description: 'The local host is represented with `null`.',
+				},
+			},
 		},
-	},
-	anyOf: [
-		{ required: ['userId'] },
-		{ required: ['userIds'] },
-		{ required: ['username'] },
 	],
 } as const;
 
@@ -102,9 +123,11 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 			let user;
 
 			const isModerator = await this.roleService.isModerator(me);
-			ps.username = ps.username?.trim();
+			if ('username' in ps) {
+				ps.username = ps.username.trim();
+			}
 
-			if (ps.userIds) {
+			if ('userIds' in ps) {
 				if (ps.userIds.length === 0) {
 					return [];
 				}
@@ -129,7 +152,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				return _users.map(u => _userMap.get(u.id)!);
 			} else {
 				// Lookup user
-				if (typeof ps.host === 'string' && typeof ps.username === 'string') {
+				if (typeof ps.host === 'string' && 'username' in ps) {
 					if (this.serverSettings.ugcVisibilityForVisitor === 'local' && me == null) {
 						throw new ApiError(meta.errors.noSuchUser);
 					}
@@ -139,7 +162,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 						throw new ApiError(meta.errors.failedToResolveRemoteUser);
 					});
 				} else {
-					const q: FindOptionsWhere<MiUser> = ps.userId != null
+					const q: FindOptionsWhere<MiUser> = 'userId' in ps
 						? { id: ps.userId }
 						: { usernameLower: ps.username!.toLowerCase(), host: IsNull() };