fix(API): Give a union of object schemas a root type: object in the generated spec (no-changelog) (#40409)

Co-authored-by: Claude Opus 5.5 <[email protected]>

packages/cli/src/public-api/v1/handlers/audit/spec/paths/generateAudit.generated.yml

@@ -129,6 +129,7 @@ responses:
                                     - kind
                                     - nodeType
                                     - filePath
+                              type: object
                           settings:
                             type: object
                             additionalProperties: {}
@@ -244,6 +245,7 @@ responses:
                                     - kind
                                     - nodeType
                                     - filePath
+                              type: object
                           settings:
                             type: object
                             additionalProperties: {}
@@ -362,6 +364,7 @@ responses:
                                     - kind
                                     - nodeType
                                     - filePath
+                              type: object
                           settings:
                             type: object
                             additionalProperties: {}
@@ -480,6 +483,7 @@ responses:
                                     - kind
                                     - nodeType
                                     - filePath
+                              type: object
                           settings:
                             type: object
                             additionalProperties: {}
@@ -595,6 +599,7 @@ responses:
                                     - kind
                                     - nodeType
                                     - filePath
+                              type: object
                           settings:
                             type: object
                             additionalProperties: {}

packages/cli/src/public-api/v1/handlers/credential-type-policies/spec/paths/createCredentialTypePolicyDocument.generated.yml

@@ -54,6 +54,7 @@ requestBody:
                       required:
                         - kind
                         - value
+                  type: object
               required:
                 - id
                 - action

packages/cli/src/public-api/v1/handlers/credential-type-policies/spec/paths/putCredentialTypeInstancePolicy.generated.yml

@@ -54,6 +54,7 @@ requestBody:
                       required:
                         - kind
                         - value
+                  type: object
               required:
                 - id
                 - action

packages/cli/src/public-api/v1/handlers/credential-type-policies/spec/paths/putCredentialTypeProjectPolicy.generated.yml

@@ -60,6 +60,7 @@ requestBody:
                       required:
                         - kind
                         - value
+                  type: object
               required:
                 - id
                 - action

packages/cli/src/public-api/v1/handlers/credential-type-policies/spec/paths/updateCredentialTypePolicyDocument.generated.yml

@@ -61,6 +61,7 @@ requestBody:
                       required:
                         - kind
                         - value
+                  type: object
               required:
                 - id
                 - action

packages/cli/src/public-api/v1/handlers/node-type-policies/spec/paths/createNodeTypePolicyDocument.generated.yml

@@ -54,6 +54,7 @@ requestBody:
                       required:
                         - kind
                         - value
+                  type: object
               required:
                 - id
                 - action

packages/cli/src/public-api/v1/handlers/node-type-policies/spec/paths/putNodeTypeInstancePolicy.generated.yml

@@ -54,6 +54,7 @@ requestBody:
                       required:
                         - kind
                         - value
+                  type: object
               required:
                 - id
                 - action

packages/cli/src/public-api/v1/handlers/node-type-policies/spec/paths/putNodeTypeProjectPolicy.generated.yml

@@ -60,6 +60,7 @@ requestBody:
                       required:
                         - kind
                         - value
+                  type: object
               required:
                 - id
                 - action

packages/cli/src/public-api/v1/handlers/node-type-policies/spec/paths/updateNodeTypePolicyDocument.generated.yml

@@ -61,6 +61,7 @@ requestBody:
                       required:
                         - kind
                         - value
+                  type: object
               required:
                 - id
                 - action

packages/cli/src/public-api/v1/handlers/promotions/spec/paths/createPromotionProvider.generated.yml

@@ -56,6 +56,7 @@ requestBody:
                   - username
                   - password
                 additionalProperties: false
+            type: object
         required:
           - name
           - type

packages/cli/src/public-api/v1/handlers/promotions/spec/paths/updatePromotionProvider.generated.yml

@@ -58,6 +58,7 @@ requestBody:
                   - username
                   - password
                 additionalProperties: false
+            type: object
         additionalProperties: false
         minProperties: 1
 responses:

packages/cli/src/public-api/v1/handlers/settings/spec/paths/createLogStreamingDestination.generated.yml

@@ -366,6 +366,7 @@ requestBody:
               - type
               - dsn
         description: 'A log streaming destination. The `type` field selects the variant and its type-specific fields: `webhook`, `syslog`, or `sentry`.'
+        type: object
 responses:
   '200':
     description: Operation successful.

packages/cli/src/public-api/v1/handlers/settings/spec/paths/getLogStreamingDestinations.generated.yml

@@ -372,6 +372,7 @@ responses:
                       - dsn
                       - id
                 description: 'A log streaming destination. The `type` field selects the variant and its type-specific fields: `webhook`, `syslog`, or `sentry`.'
+                type: object
               description: The configured log streaming destinations.
           required:
             - data

packages/cli/src/public-api/v1/handlers/settings/spec/paths/updateLogStreamingDestination.generated.yml

@@ -358,6 +358,7 @@ requestBody:
               - type
               - dsn
         description: 'A log streaming destination. The `type` field selects the variant and its type-specific fields: `webhook`, `syslog`, or `sentry`.'
+        type: object
 responses:
   '200':
     description: Operation successful.

packages/cli/src/public-api/v1/openapi-gen/__tests__/object-union-type.test.ts

@@ -0,0 +1,55 @@
+import { addObjectTypeToObjectUnions } from '../object-union-type';
+
+const webhook = { type: 'object', properties: { url: { type: 'string' } } };
+const syslog = { type: 'object', properties: { host: { type: 'string' } } };
+
+describe('addObjectTypeToObjectUnions', () => {
+	it('adds `type: object` to a oneOf whose members are all objects', () => {
+		const schema = { oneOf: [webhook, syslog], description: 'A destination' };
+		addObjectTypeToObjectUnions(schema);
+		expect(schema).toEqual({
+			type: 'object',
+			oneOf: [webhook, syslog],
+			description: 'A destination',
+		});
+	});
+
+	it('leaves a oneOf with a non-object member unchanged', () => {
+		const schema = { oneOf: [webhook, { type: 'array', items: {} }] };
+		addObjectTypeToObjectUnions(schema);
+		expect(schema).toEqual({ oneOf: [webhook, { type: 'array', items: {} }] });
+	});
+
+	it('leaves a oneOf with a $ref member unchanged', () => {
+		const schema = { oneOf: [webhook, { $ref: '#/components/schemas/Syslog' }] };
+		addObjectTypeToObjectUnions(schema);
+		expect(schema).toEqual({ oneOf: [webhook, { $ref: '#/components/schemas/Syslog' }] });
+	});
+
+	it('normalizes a nested union under items', () => {
+		const schema = { type: 'array', items: { oneOf: [webhook, syslog] } };
+		addObjectTypeToObjectUnions(schema);
+		expect(schema).toEqual({ type: 'array', items: { type: 'object', oneOf: [webhook, syslog] } });
+	});
+
+	it('normalizes a union under a property named like a data key', () => {
+		const schema = {
+			type: 'object',
+			properties: { default: { oneOf: [webhook, syslog] }, enum: { oneOf: [webhook, syslog] } },
+		};
+		addObjectTypeToObjectUnions(schema);
+		expect(schema).toEqual({
+			type: 'object',
+			properties: {
+				default: { type: 'object', oneOf: [webhook, syslog] },
+				enum: { type: 'object', oneOf: [webhook, syslog] },
+			},
+		});
+	});
+
+	it('does not rewrite example data', () => {
+		const schema = { type: 'object', example: { oneOf: [webhook, syslog] } };
+		addObjectTypeToObjectUnions(schema);
+		expect(schema).toEqual({ type: 'object', example: { oneOf: [webhook, syslog] } });
+	});
+});

packages/cli/src/public-api/v1/openapi-gen/decorator-routes.ts

@@ -20,7 +20,7 @@ import {
 	toOpenApiPathTemplate,
 } from '@/public-api/public-api-route-resolver';
 
-import { stripUntypedNullable } from './untyped-nullable';
+import { applySchemaModifiers } from './schema-modifiers';
 
 const REQUEST_BODY_COMPONENT = 'RequestBody';
 
@@ -194,9 +194,7 @@ export function buildRequestBodyJsonSchema(
 	const { components } = new OpenApiGeneratorV3(registry.definitions).generateComponents();
 	const schema = components?.schemas?.[REQUEST_BODY_COMPONENT];
 
-	// Keep in sync with `buildArtifactsFromRegistry`, both convert the same DTOs to OpenAPI
-	// and `/discover` serves this schema straight from a route at runtime.
-	stripUntypedNullable(schema);
+	applySchemaModifiers(schema);
 
 	return isRecord(schema) ? schema : undefined;
 }

packages/cli/src/public-api/v1/openapi-gen/generate.ts

@@ -15,7 +15,7 @@ import {
 	type NamedResponseDto,
 	type SchemaResolver,
 } from './decorator-routes';
-import { stripUntypedNullable } from './untyped-nullable';
+import { applySchemaModifiers } from './schema-modifiers';
 
 const COMPONENT_SCHEMA_REF = /^#\/components\/schemas\/(.+)$/;
 const SHARED_SCHEMA_DIR = 'shared/spec/schemas';
@@ -90,9 +90,7 @@ export function buildArtifactsFromRegistry(
 		info: { title: 'throwaway', version: '0.0.0' },
 	});
 
-	// zod-to-openapi emits `z.unknown()`/`z.any()` as `{ nullable: true }` with no `type` which
-	// express-openapi-validator rejects at schema-compile time once bundled.
-	stripUntypedNullable(document);
+	applySchemaModifiers(document);
 
 	const artifacts: GeneratedArtifact[] = [];
 

packages/cli/src/public-api/v1/openapi-gen/object-union-type.ts

@@ -0,0 +1,43 @@
+import { isRecord } from '@n8n/utils/is-record';
+
+const DATA_VALUED_KEYS = new Set(['example', 'examples', 'default', 'enum']);
+
+// The keys inside these objects are field names, not keywords. Check every value, so a field
+// named `example` or `default` is not skipped as sample data.
+const SCHEMA_MAP_KEYS = new Set(['properties', 'patternProperties', '$defs', 'definitions']);
+
+/**
+ * zod-to-openapi writes a discriminated union as a `oneOf` with no `type`. `.openapi()` cannot add
+ * the `type` without replacing the union, so this function adds it to the generated document.
+ */
+export function addObjectTypeToObjectUnions(node: unknown): void {
+	if (Array.isArray(node)) {
+		node.forEach((item) => addObjectTypeToObjectUnions(item));
+		return;
+	}
+
+	if (!isRecord(node)) {
+		return;
+	}
+
+	const members = node.oneOf;
+	if (
+		node.type === undefined &&
+		Array.isArray(members) &&
+		members.length > 0 &&
+		members.every((member) => isRecord(member) && member.type === 'object')
+	) {
+		node.type = 'object';
+	}
+
+	for (const [key, value] of Object.entries(node)) {
+		if (SCHEMA_MAP_KEYS.has(key) && isRecord(value)) {
+			Object.values(value).forEach((schema) => addObjectTypeToObjectUnions(schema));
+			continue;
+		}
+		if (DATA_VALUED_KEYS.has(key)) {
+			continue;
+		}
+		addObjectTypeToObjectUnions(value);
+	}
+}

packages/cli/src/public-api/v1/openapi-gen/schema-modifiers.ts

@@ -0,0 +1,10 @@
+import { addObjectTypeToObjectUnions } from './object-union-type';
+import { stripUntypedNullable } from './untyped-nullable';
+
+const SCHEMA_MODIFIERS = [stripUntypedNullable, addObjectTypeToObjectUnions];
+
+export function applySchemaModifiers(node: unknown): void {
+	for (const modify of SCHEMA_MODIFIERS) {
+		modify(node);
+	}
+}

packages/cli/src/public-api/v1/shared/spec/schemas/applyPackageResultDto.generated.yml

@@ -454,6 +454,7 @@ oneOf:
                           required:
                             - kind
                             - project
+                      type: object
                     sourceValue:
                       type: string
                       maxLength: 1000
@@ -496,6 +497,7 @@ oneOf:
                     - name
                     - scope
                     - consumers
+              type: object
           accessRequirements:
             type: array
             items:
@@ -1253,6 +1255,7 @@ oneOf:
                               - from
                               - to
                               - destructive
+                        type: object
                       minItems: 1
                   required:
                     - kind
@@ -1261,6 +1264,7 @@ oneOf:
                     - name
                     - consumers
                     - changes
+              type: object
           warnings:
             type: array
             items:
@@ -1367,3 +1371,4 @@ oneOf:
       - configId
       - git
       - status
+type: object

packages/cli/src/public-api/v1/shared/spec/schemas/importBlockingIssue.generated.yml

@@ -443,6 +443,7 @@ oneOf:
                 - to
                 - destructive
           description: A single change `dataTableSchemaConflictPolicy=overwrite` would make (or made) to a matched target table's schema. `destructive` operations delete the data in a column.
+          type: object
         description: 'For `schema-incompatible`: the changes `overwrite` would make to the target table.'
       missingScope:
         type: string
@@ -642,3 +643,4 @@ oneOf:
       - name
       - violations
     description: 'A workflow the content-import policy refused. Takes down the whole package rather than skipping the workflow: the import rewrites cross-workflow references to the ids each workflow would get, so dropping one leaves the workflows that call it pointing at a row nothing ever wrote.'
+type: object

packages/cli/src/public-api/v1/shared/spec/schemas/logStreamingDestinationPublicDto.generated.yml

@@ -352,3 +352,4 @@ oneOf:
       - dsn
       - id
 description: 'A log streaming destination. The `type` field selects the variant and its type-specific fields: `webhook`, `syslog`, or `sentry`.'
+type: object

packages/cli/src/public-api/v1/shared/spec/schemas/policyAttachmentsPublicDto.generated.yml

@@ -47,6 +47,7 @@ properties:
                     required:
                       - kind
                       - value
+                type: object
             required:
               - id
               - action

packages/cli/src/public-api/v1/shared/spec/schemas/policyDocumentListPublicDto.generated.yml

@@ -49,6 +49,7 @@ properties:
                     required:
                       - kind
                       - value
+                type: object
             required:
               - id
               - action

packages/cli/src/public-api/v1/shared/spec/schemas/policyDocumentPublicDto.generated.yml

@@ -44,6 +44,7 @@ properties:
               required:
                 - kind
                 - value
+          type: object
       required:
         - id
         - action

packages/cli/src/public-api/v1/shared/spec/schemas/policyDocumentWriteResultPublicDto.generated.yml

@@ -47,6 +47,7 @@ properties:
                   required:
                     - kind
                     - value
+              type: object
           required:
             - id
             - action

packages/cli/src/public-api/v1/shared/spec/schemas/policyEffectivePublicDto.generated.yml

@@ -43,6 +43,7 @@ properties:
               required:
                 - kind
                 - value
+          type: object
       required:
         - id
         - action

packages/cli/src/public-api/v1/shared/spec/schemas/policyEffectiveWriteResultPublicDto.generated.yml

@@ -43,6 +43,7 @@ properties:
               required:
                 - kind
                 - value
+          type: object
       required:
         - id
         - action